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RFC 7906 - NSA's Cryptographic Message Syntax (CMS) Key Manageme


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Independent Submission                                         P. Timmel
Request for Comments: 7906                      National Security Agency
Category: Informational                                       R. Housley
ISSN: 2070-1721                                           Vigil Security
                                                               S. Turner
                                                                    IECA
                                                               June 2016

   NSA's Cryptographic Message Syntax (CMS) Key Management Attributes

Abstract

   This document defines key management attributes used by the National
   Security Agency (NSA).  The attributes can appear in asymmetric
   and/or symmetric key packages as well as the Cryptographic Message
   Syntax (CMS) content types that subsequently envelope the key
   packages.  Key packages described in RFCs 5958 and 6031 are examples
   of where these attributes can be used.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7906.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1. Introduction ....................................................3
      1.1. Attribute Locations ........................................3
      1.2. ASN.1 Notation .............................................4
      1.3. Terminology ................................................5
   2. CMS-Defined Attributes ..........................................6
   3. Community Identifiers ...........................................7
   4. Key Province Attribute ..........................................8
   5. Binary Signing Time .............................................8
   6. Manifest ........................................................9
   7. Key Algorithm ...................................................9
   8. User Certificate ...............................................11
   9. Key Package Receivers ..........................................11
   10. TSEC Nomenclature .............................................13
   11. Key Purpose ...................................................16
   12. Key Use .......................................................17
   13. Transport Key .................................................20
   14. Key Distribution Period .......................................20
   15. Key Validity Period ...........................................22
   16. Key Duration ..................................................23
   17. Classification ................................................24
      17.1. Security Label ...........................................25
   18. Split Key Identifier ..........................................29
   19. Key Package Type ..............................................30
   20. Signature Usage ...............................................30
   21. Other Certificate Format ......................................33
   22. PKI Path ......................................................34
   23. Useful Certificates ...........................................35
   24. Key Wrap Algorithm ............................................35
   25. Content Decryption Key Identifier .............................36
      25.1. Content Decryption Key Identifier: Symmetric Key
            and Symmetric ............................................36
      25.2. Content Decryption Key Identifier: Unprotected ...........37
   26. Certificate Pointers ..........................................37
   27. CRL Pointers ..................................................38
   28. Key Package Identifier and Receipt Request ....................38
   29. Additional Error Codes ........................................39
   30. Processing Key Package Attribute Values and CMS
       Content Constraints ...........................................39
   31. Attribute Scope ...............................................41
   32. Security Considerations .......................................48
   33. References ....................................................48
      33.1. Normative References .....................................48
      33.2. Informative References ...................................51
   Appendix A. ASN.1 Module ..........................................52
   Authors' Addresses ................................................68

1.  Introduction

   This document defines key management attributes used by the National
   Security Agency (NSA).  The attributes can appear in asymmetric
   and/or symmetric key packages as well as the Cryptographic Message
   Syntax (CMS) content types that subsequently envelope the key
   packages.

   This document contains definitions for new attributes as well as
   previously defined attributes.  References are provided to the
   previously defined attributes; however, their definitions are
   included herein for convenience.

   CMS allows for arbitrary nesting of content types.  Attributes are
   also supported in various locations in content types and key
   packages, which are themselves content types (see Section 1.1).  An
   implementation that supports all of the possibilities would be
   extremely complex.  Instead of implementing the full flexibility
   supported by this document, some devices may choose to support one or
   more templates, which is a profile for a combination of CMS content
   type(s), key package, and attribute(s); see Section 19.

1.1.  Attribute Locations

   There are a number of CMS content types that support attributes
   SignedData [RFC5652], EnvelopedData [RFC5652], EncryptedData
   [RFC5652], AuthenticatedData [RFC5652], and AuthEnvelopedData
   [RFC5083] as well as ContentWithAttributes [RFC4073].  There are also
   a number of other content types defined with CONTENT-TYPE [RFC6268]
   that support attributes including AsymmetricKeyPackage [RFC5958] and
   SymmetricKeyPackage [RFC6031].

   CMS defines a number of "protecting content types" -- SignedData
   [RFC5652], EnvelopedData [RFC5652], EncryptedData [RFC5652],
   AuthenticatedData [RFC5652], and AuthEnvelopedData [RFC5083] -- that
   provide some type of security service.  There are also other CMS
   content types -- Data [RFC5652], ContentWithAttributes [RFC4073], and
   ContentCollection [RFC4073] -- that provide no security service.

   There are also different kinds of attributes in these content types:

      o  SignedData supports two kinds of attributes: signed and
         unsigned attributes in the signedAttrs and unsignedAttrs
         fields, respectively.

      o  EnvelopedData and EncryptedData each support one kind of
         attribute: unprotected attributes in the unprotectedAttrs
         field.

      o  AuthEnvelopedData supports two kinds of attributes:
         authenticated and unauthenticated attributes in the authAttrs
         and unauthAttrs fields, respectively.  Both of these attributes
         are also unprotected (i.e., they are not encrypted); therefore,
         when referring to AuthEnvelopedData attributes, they are
         authenticated&unprotected and unauthenticated&unprotected.  For
         this specification, unauthenticated attributes MUST NOT be
         included.

      o  AuthenticatedData supports two kinds of attributes:
         authenticated and unauthenticated attributes in the authAttrs
         and unauthAttrs fields, respectively.  For this specification,
         unauthenticated attributes MUST NOT be included.

      o  ContentWithAttributes supports one kind of attribute: content
         attributes in the attrs field.

      o  AsymmetricKeyPackage supports one kind of attribute: asymmetric
         key attributes in the attributes field.  If an attribute
         appears as part of an asymmetric key package, it SHOULD appear
         in the attributes field of the AsymmetricKeyPackage.

      o  SymmetricKeyPackage supports two kinds of attributes: symmetric
         key and symmetric key package attributes in the sKeyAttrs and
         sKeyPkgAttrs fields, respectively.  Note that [RFC6031]
         prohibits the same attribute from appearing in both locations
         in the same SymmetricKeyPackage.

   Note that this specification updates the following information object
   sets SignedAttributesSet, UnsignedAttributes,
   UnprotectedEnvAttributes, UnprotectedEncAttributes, AuthAttributeSet,
   UnauthAttributeSet, AuthEnvDataAttributeSet,
   UnauthEnvDataAttributeSet, and ContentAttributeSet from [RFC6268] as
   well as OneAsymmetricKeyAttributes from [RFC5958], SKeyPkgAttributes
   from [RFC6031], and SKeyAttributes from [RFC6031] to constrain the
   permissible locations for attributes.  See Appendix A for the ASN.1
   for the information object sets.

1.2.  ASN.1 Notation

   The attributes defined in this document use 2002 ASN.1 [X.680]
   [X.681] [X.682] [X.683].  The attributes MUST be DER [X.690] encoded.

   Each of the attributes has a single attribute value instance in the
   values set.  Even though the syntax is defined as a set, there MUST
   be exactly one instance of AttributeValue present.  Further, the
   SignedAttributes, UnsignedAttributes, UnprotectedAttributes,
   AuthAttributes, and UnauthAttributes are also defined as a set, and

   this set MUST include only one instance of any particular type of
   attribute.  That is, any object identifier appearing in AttributeType
   MUST only appear one time in the set of attributes.

   SignedData, EnvelopedData, EncryptedData, AuthenticatedData,
   AuthEnvelopedData, and ContentWithAttributes were originally defined
   using the 1988 version of ASN.1.  These definitions were updated to
   the 2008 version of ASN.1 by [RFC6268].  None of the new 2008 ASN.1
   tokens are used; this allows 2002 compilers to compile 2008 ASN.1.
   AsymmetricKeyPackage and SymmetricKeyPackage are defined using the
   2002 ASN.1.

   [RFC5652] and [RFC2634] define generally useful attributes for CMS
   using the 1988 version of ASN.1.  These definitions were updated to
   the 2008 version of ASN.1 by [RFC6268] and the 2002 version of ASN.1
   by [RFC5911], respectively.  [RFC4108] and [RFC6019] also defined
   attributes using the 1988 version of ASN.1, which this document uses.
   Both were updated by [RFC5911] to the 2002 ASN.1.  Refer to
   [RFC2634], [RFC4108], [RFC5652], and [RFC6019] for the attribute's
   semantics, but refer to [RFC5911] or [RFC6268] for the attribute's
   ASN.1 syntax.

1.3.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in RFC
   2119 [RFC2119].

   Attribute Scope: The scope of an attribute is the compilation of
   keying material to which the attribute value is assigned.  The scope
   of each attribute is determined by its placement within the key
   package or content collection.  See Section 31.

   SIR: Source Intermediary Receiver is a model with three entities:

      o  A source initiates the delivery of a key to one or more
         receivers.  It may wrap or encrypt the key for delivery.  This
         is expected to be the common case, since a cleartext key is
         vulnerable to exposure and compromise.  If the sender is to
         encrypt the key for delivery, it must know how to encrypt the
         key so that the receiver(s) can decrypt it.  A sender may also
         carry out any of the functions of an intermediary.

         *  The original key package creators are sometimes referred to
            as key source authorities.  These entities create the
            symmetric and/or asymmetric key package and apply the
            initial CMS protecting layer, which is normally a SignedData

            but sometimes an AuthenticatedData.  This initial CMS
            protecting layer is maintained through any intermediary for
            the receivers of the key package to ensure that receivers
            can validate the key source authority.

      o  An intermediary does not have access to the cleartext key.  An
         intermediary may perform source authentication on key packages
         and may append or remove management information related to the
         package.  It may encapsulate the encrypted key packages in
         larger packages that contain other user data destined for later
         intermediaries or receivers.

      o  A receiver has access to the cleartext key. If the received key
         package is encrypted, it can unwrap or decrypt the encrypted
         key to obtain the cleartext key.  A receiver may be the final
         destination of the cryptographic product.  An element that acts
         as a receiver and is not the final destination of the key
         package may also act as a sender or as an intermediary.  After
         receiving a key, a receiver may encrypt the received key for
         local storage.

   NOTE: As noted in Section 1, a receiver can be tailored to support a
   particular combination of CMS content type(s), key package, and
   attribute(s) resulting in less-complex implementations.  All of these
   tailored receivers can be supported by a common key management
   infrastructure that uses this specification; this also can yield
   efficiencies in generation and provisioning.  Senders and
   intermediaries that have to understand multiple tailored receivers
   get the efficiency of a common specification language and modular
   implementation, as opposed to needing stove-piped processing for each
   different receiver.

2.  CMS-Defined Attributes

   The following attributes are defined for [RFC5652]:

      o  content-type [RFC5652] [RFC5911] [RFC6268] uniquely specifies
         the CMS content type.  This attribute MUST be included as a
         signed, authenticated, or authenticated&unprotected attribute.

      o  message-digest [RFC5652] [RFC5911] [RFC6268] is the message
         digest of the encapsulated content calculated using the
         signer's message digest algorithm.  As specified in [RFC5652],
         it must be included as a signed attribute and an authenticated
         attribute; as specified in [RFC5652], it must not be an
         unsigned attribute, unauthenticated attribute, or unprotected

         attribute; as specified in [RFC5083], it should not be included
         as an authenticated&unprotected attribute in AuthEnvelopedData.
         This attribute MUST NOT be included elsewhere.

      o  content-hints [RFC2634] [RFC5911] [RFC6268] identifies the
         innermost content when multiple layers of encapsulation have
         been applied.  Every instance of SignedData, AuthenticatedData,
         and AuthEnvelopedData that does not directly encapsulate a
         SymmetricKeyPackage, an AsymmetricKeyPackage, or an
         EncryptedKeyPackage [RFC6032] MUST include this attribute.

3.  Community Identifiers

   The community-identifiers attribute, defined in [RFC4108] and
   [RFC5911], lists the communities that are authorized recipients of
   the signed content.  It can appear as a signed, authenticated,
   authenticated&unprotected, or content attribute.  This attribute MUST
   be supported.

   The 2002 ASN.1 syntax for the community-identifiers attribute is
   included for convenience:

     aa-communityIdentifiers ATTRIBUTE ::= {
       TYPE CommunityIdentifiers
       IDENTIFIED BY id-aa-communityIdentifiers }

     id-aa-communityIdentifiers OBJECT IDENTIFIER ::= {
       iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
       smime(16) aa(2) 40 }

     CommunityIdentifiers ::= SEQUENCE OF CommunityIdentifier

     CommunityIdentifier ::= CHOICE {
       communityOID  OBJECT IDENTIFIER,
       hwModuleList  HardwareModules }

     HardwareModules ::= SEQUENCE {
       hwType           OBJECT IDENTIFIER,
       hwSerialEntries  SEQUENCE OF HardwareSerialEntry }

     HardwareSerialEntry ::= CHOICE {
       all    NULL,
       single OCTET STRING,
       block  SEQUENCE {
                low OCTET STRING,
                high OCTET STRING } }

   Consult [RFC4108] for the attribute's semantics.

4.  Key Province Attribute

   The key-province-v2 attribute identifies the scope, range, or
   jurisdiction in which the key is to be used.  The key-province-v2
   attribute MUST be present as a signed attribute or an authenticated
   attribute in the innermost CMS protection content type that provides
   authentication (i.e., SignedData, AuthEnvelopedData, or
   AuthenticatedData) and encapsulates a symmetric key package or an
   asymmetric key package.

   The key-province attribute has the following syntax:

     aa-keyProvince-v2 ATTRIBUTE ::= {
       TYPE KeyProvinceV2
       IDENTIFIED BY id-aa-KP-keyProvinceV2 }

     id-aa-KP-keyProvinceV2 OBJECT IDENTIFIER ::=
       { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
         dod(2) infosec(1) attributes(5) 71 }

     KeyProvinceV2 ::= OBJECT IDENTIFIER

5.  Binary Signing Time

   The binary-signing-time attribute, defined in [RFC6019] and
   [RFC6268], specifies the time at which the signature or the Message
   Authentication Code (MAC) was applied to the encapsulated content.
   It can appear as a signed, authenticated, or
   authenticated&unprotected attribute.

   The 2002 ASN.1 syntax is included for convenience:

     aa-binarySigningTime ATTRIBUTE ::= {
       TYPE BinarySigningTime
       IDENTIFIED BY id-aa-binarySigningTime }

     id-aa-binarySigningTime OBJECT IDENTIFIER ::= {
       iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
       smime(16) aa(2) 46 }

     BinarySigningTime ::= BinaryTime

     BinaryTime ::= INTEGER (0..MAX)

   Consult [RFC6019] for the binary-signing-time attribute's semantics.

6.  Manifest

   The manifest attribute lists the short titles of all the Transmission
   Security Nomenclature (TSEC-Nomenclature) attributes from inner key
   packages.  It MUST only appear as an outermost signed, authenticated,
   or authenticated&unprotected attribute.  If a short title is repeated
   in inner packages, it need only appear once in the manifest
   attribute.  The manifest attribute MUST NOT appear in the same level
   as the TSEC-Nomenclature from Section 10.

   The manifest attribute has the following syntax:

     aa-manifest ATTRIBUTE ::= {
       TYPE Manifest
       IDENTIFIED BY id-aa-KP-manifest }

     id-aa-KP-manifest OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1)
       gov(101) dod(2) infosec(1) attributes(5) 72 }

     Manifest ::= SEQUENCE SIZE (1..MAX) OF ShortTitle

7.  Key Algorithm

   The key-algorithm attribute indirectly specifies the size and format
   of the keying material in the skey field of a symmetric key package,
   which is defined in [RFC6031].  It can appear as a symmetric key,
   symmetric key package, signed, authenticated,
   authenticated&unprotected, or content attribute.  If this attribute
   appears as a signed attribute, then all of the keying material within
   the SignedData content MUST be associated with the same algorithm.
   If this attribute appears as an authenticated or
   authenticated&unprotected attribute, then all of the keying material
   within the AuthenticatedData or AuthEnvelopedData content type MUST
   be associated with the same algorithm.  If this attribute appears as
   a content attribute, then all of the keying material within the
   collection MUST be associated with the same algorithm.  If both the
   key-wrap-algorithm (Section 24) and key-algorithm attributes apply to
   an sKey, then the key-algorithm attribute refers to the decrypted
   value of sKey rather than to the content of sKey itself.  This
   attribute MUST be supported.

   The key-algorithm attribute has the following syntax:

     aa-keyAlgorithm ATTRIBUTE ::= {
       TYPE KeyAlgorithm
       IDENTIFIED BY id-kma-keyAlgorithm }

     id-kma-keyAlgorithm OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1)
       gov(101) dod(2) infosec(1) keying-material-attributes(13) 1 }

     KeyAlgorithm ::= SEQUENCE {
       keyAlg            OBJECT IDENTIFIER,
       checkWordAlg  [1] OBJECT IDENTIFIER OPTIONAL,
       crcAlg        [2] OBJECT IDENTIFIER OPTIONAL }

   The fields in the key-algorithm attribute have the following
   semantics:

      o  keyAlg specifies the size and format of the keying material.

      o  If the particular key format supports more than one check-word
         algorithm, then the OPTIONAL checkWordAlg identifier indicates
         which check-word algorithm was used to generate the check word
         that is present.  If the check-word algorithm is implied by the
         key algorithm, then the checkWordAlg field SHOULD be omitted.

      o  If the particular key format supports more than one Cyclic
         Redundancy Check (CRC) algorithm, then the OPTIONAL crcAlg
         identifier indicates which CRC algorithm was used to generate
         the value that is present.  If the CRC algorithm is implied by
         the key algorithm, then the crcAlg field SHOULD be omitted.

   The keyAlg identifier, the checkWordAlg identifier, and the crcAlg
   identifier are object identifiers.  The use of an object identifier
   accommodates any algorithm from any registry.

   The format of the keying material in the skey field of a symmetric
   key package will not match this attribute if the keying material is
   split (see Section 18 for a discussion of the split-identifier
   attribute).  In this situation, this attribute identifies the format
   of the keying material once the two splits are combined.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-algorithm attribute can appear in more than one
   location in the overall key package.  When there are multiple
   occurrences of the key-algorithm attribute within the same scope, the
   keyAlg field MUST match in all instances.  The OPTIONAL checkWordAlg
   and crcAlg fields can be omitted in the key-algorithm attribute when
   it appears as a signed, authenticated, authenticated&unprotected, or
   content attribute.  However, if these optional fields are present,
   they MUST also match the other occurrences within the same scope.
   Receivers MUST reject any key package that fails these consistency
   checks.

8.  User Certificate

   The user-certificate attribute specifies the type, format, and value
   of an X.509 certificate and is used in asymmetric key package's
   attributes field.  This attribute can appear as an asymmetric key
   attribute.  This attribute MUST NOT appear in an asymmetric key
   package attributes field that includes the other-certificate-formats
   attribute.  Symmetric key packages do not contain any certificates,
   so the user-certificate attribute MUST NOT appear in a symmetric key
   package.  The user-certificate attribute MUST NOT appear as a signed,
   authenticated, authenticated&unprotected, or content attribute.  This
   attribute MUST be supported.

   The syntax is taken from [X.509] but redefined using the ATTRIBUTE
   CLASS from [RFC5912].  The user-certificate attribute has the
   following syntax:

     aa-userCertificate ATTRIBUTE ::= {
       TYPE Certificate
       EQUALITY MATCHING RULE certificateExactMatch
       IDENTIFIED BY id-at-userCertificate }

     id-at-userCertificate OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) ds(5) attributes(4) 36 }

   Since the user-certificate attribute MUST NOT appear as a signed,
   authenticated, authenticated&unprotected, or content attribute, an
   asymmetric key package cannot include multiple occurrences of the
   user-certificate attribute within the same scope.  Receivers MUST
   reject any asymmetric key package in which the user-certificate
   attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute.

9.  Key Package Receivers

   The key-package-receivers-v2 attribute indicates the intended
   audience for the key package.  The key-package-receivers-v2 attribute
   is not intended for access control decisions; rather, intermediate
   systems may use this attribute to make routing and relaying
   decisions.  If the receiver is not listed, it will not be able to
   decrypt the package; therefore, the receiver SHOULD reject the key
   package if the key-package-receivers-v2 attribute is present and they
   are not listed as an intended receiver.  The key-package-receivers-v2
   attribute can be used as a signed, authenticated,
   authenticated&unprotected, or content attribute.  If the key-package-
   receivers-v2 attribute is associated with a collection, then the
   named receivers MUST be able to receive all of the key packages
   within the collection.  This attribute MUST be supported.

   The key-package-receivers-v2 attribute has the following syntax:

     aa-keyPackageReceivers-v2 ATTRIBUTE ::= {
       TYPE KeyPkgReceiversV2
       IDENTIFIED BY id-kma-keyPkgReceiversV2 }

     id-kma-keyPkgReceiversV2 OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 16 }

     KeyPkgReceiversV2 ::= SEQUENCE SIZE (1..MAX) OF KeyPkgReceiver

     KeyPkgReceiver ::= CHOICE {
       sirEntity  [0] SIREntityName,
       community  [1] CommunityIdentifier }

   The key-package-receivers-v2 attribute contains a list of receiver
   identifiers.  The receiver identifier is either a SIREntityName
   [RFC7191] or a CommunityIdentifier (see Section 3).  The
   SIREntityName syntax does not impose any particular structure on the
   receiver identifier, but it does require registration of receiver
   identifier types.  The nameType ensures that two receiver identifiers
   of different types that contain the same values are not interpreted
   as equivalent.  Name types are expected to be defined that represent
   several different granularities.  For example, one name type will
   represent the receiver organization.  At a finer granularity, the
   name type will identify a specific cryptographic device, perhaps
   using a manufacturer identifier and serial number.

   If a receiver does not recognize a particular nameType or a community
   identifier, then keying material within the scope of the unrecognized
   nameType or community identifier MUST NOT be used in any manner.
   However, the receiver need not discard the associated key package.
   Since many cryptographic devices are programmable, a different
   firmware load may recognize the nameType.  Likewise, a change in the
   configuration may lead to the recognition of a previously
   unrecognized community identifier.  Therefore, the receiver may
   retain the key package, but refuse to use it for anything with a
   firmware load that does not recognize the nameType or a configuration
   that does not recognize the community identifier.

   Whenever a key package is saved for later processing due to an
   unrecognized nameType or community identifier, subsequent processing
   MUST NOT rely on any checks that were made the first time the key
   package processing was attempted.  That is, the subsequent processing
   MUST include the full complement of checks.  Further, a receipt for
   the packages MUST NOT be generated unless all of these checks are
   successfully completed.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-package-receivers-v2 attribute can appear in
   more than one location in the overall key package.  When that
   happens, each occurrence is evaluated independently.

   In a content collection, each member of the collection might contain
   its own signed, authenticated, authenticated&unprotected, or content
   attribute that includes a key-package-receivers-v2 attribute.  In
   this situation, each member of the collection is evaluated
   separately, and any member that includes an acceptable receiver
   SHOULD be retained.  Other members can be rejected or retained for
   later processing with a different firmware load.

10.  TSEC Nomenclature

   The Telecommunications Security Nomenclature (TSEC-Nomenclature)
   attribute provides the name for a piece of keying material, which
   always includes a printable string called a "short title" (see
   below).  The TSEC-Nomenclature attribute also contains other
   identifiers when the shortTitle is insufficient to uniquely name a
   particular piece of keying material.  This attribute can appear as a
   symmetric key, symmetric key package, asymmetric key, signed,
   authenticated, authenticated&unprotected, or content attribute.  If
   this attribute appears in the sKeyAttrs field, the editionID,
   registerID, and segmentID attribute fields MUST NOT be ranges.  If
   this attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, all of the keying
   material within the associated content MUST have the same shortTitle,
   and the attribute value MUST contain only a shortTitle.  That is,
   when this attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, all of the optional
   fields MUST be absent.  If this attribute is associated with a
   collection, all of the keying material within the collection MUST
   have the same shortTitle; however, the editionID, registerID, and
   segmentID will be different for each key package in the collection.
   This attribute MUST be supported.

   The TSEC-Nomenclature attribute has the following syntax:

     aa-tsecNomenclature ATTRIBUTE ::= {
       TYPE TSECNomenclature
       IDENTIFIED BY id-kma-TSECNomenclature }

     id-kma-TSECNomenclature OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 3 }

     TSECNomenclature ::= SEQUENCE {
       shortTitle  ShortTitle,
       editionID   EditionID OPTIONAL,
       registerID  RegisterID OPTIONAL,
       segmentID   SegmentID OPTIONAL }

     ShortTitle ::= PrintableString

     EditionID ::= CHOICE {
       char CHOICE {
           charEdition       [1] CharEdition,
           charEditionRange  [2] CharEditionRange }
       num CHOICE {
           numEdition        [3] NumEdition,
           numEditionRange   [4] NumEditionRange } }

     CharEdition ::= PrintableString

     CharEditionRange ::= SEQUENCE {
       firstCharEdition  CharEdition,
       lastCharEdition   CharEdition }

     NumEdition ::= INTEGER (0..308915776)

     NumEditionRange ::= SEQUENCE {
       firstNumEdition  NumEdition,
       lastNumEdition   NumEdition }

     RegisterID ::= CHOICE {
       register       [5] Register,
       registerRange  [6] RegisterRange }

     Register ::= INTEGER (0..2147483647)

     RegisterRange ::= SEQUENCE {
       firstRegister  Register,
       lastRegister   Register }

     SegmentID ::= CHOICE {
       segmentNumber  [7] SegmentNumber,
       segmentRange   [8] SegmentRange }

     SegmentNumber ::= INTEGER (1..127)

     SegmentRange ::= SEQUENCE {
       firstSegment  SegmentNumber,
       lastSegment   SegmentNumber }

   The fields in the TSEC-Nomenclature attribute have the following
   semantics:

      o  The shortTitle consists of up to 32 alphanumeric characters.
         shortTitle processing always uses the value in its entirety.

      o  The editionID is OPTIONAL, and the editionIdentifier is used to
         distinguish accountable items.  The editionID consists of
         either six alphanumeric characters or an integer.  When
         present, the editionID is either a single value or a range.
         The integer encoding should be used when it is important to
         keep key package size to a minimum.

      o  The registerID is OPTIONAL.  For electronic keying material,
         the registerID is usually omitted.  The registerID is an
         accounting number assigned to identify Communications Security
         (COMSEC) material.  The registerID is either a single value or
         a range.

      o  The segmentID is OPTIONAL, and it distinguishes the individual
         symmetric keys delivered in one edition.  A unique
         segmentNumber is assigned to each key in an edition.  The
         segmentNumber is set to one for the first item in each edition,
         and it is incremented by one for each additional item within
         that edition.  The segmentID is either a single value or a
         range.

   The order that the keying material will appear in the key package is
   illustrated by the following example: a cryptographic device may
   require fresh keying material every day, an edition represents the
   keying material for a single month, and the segments represent the
   keying material for a day within that month.  Consider a key package
   that contains the keying material for July and August; it will
   contain keying material for 62 days.  The keying material will appear
   in the following order: Edition 1, Segment 1; Edition 1, Segment 2;
   Edition 1, Segment 3; ...; Edition 1, Segment 31; Edition 2,
   Segment 1; Edition 2, Segment 2; Edition 2, Segment 3; ...;
   Edition 2, Segment 31.

   Due to multiple layers of encapsulation or the use of content
   collections, the TSEC-Nomenclature attribute can appear in more than
   one location in the overall key package.  When there are multiple
   occurrences of the TSEC-Nomenclature attribute within the same scope,
   the shortTitle field MUST match in all instances.  Receivers MUST
   reject any key package that fails these consistency checks.

   When the manifest attribute from Section 6 is included in an outer
   layer, the ShortTitle field values present in TSEC-Nomenclature
   attributes MUST be one of the values in the manifest attribute.
   Receivers MUST reject any key package that fails this consistency
   check.

11.  Key Purpose

   The key-purpose attribute specifies the intended purpose of the key
   material.  It can appear as a symmetric key, symmetric key package,
   asymmetric key, signed, authenticated, authenticated&unprotected, or
   content attribute.  If the key-purpose attribute appears as a signed,
   authenticated, authenticated&unprotected, or content attribute, then
   all of the keying material within the associated content MUST have
   the same key purpose value.

   The key-purpose attribute has the following syntax:

     aa-keyPurpose ATTRIBUTE ::= {
       TYPE KeyPurpose
       IDENTIFIED BY id-kma-keyPurpose }

     id-kma-keyPurpose OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 13 }

     KeyPurpose ::= ENUMERATED {
       n-a    (0),   -- Not Applicable
       A     (65),   -- Operational
       B     (66),   -- Compatible Multiple Key
       L     (76),   -- Logistics Combinations
       M     (77),   -- Maintenance
       R     (82),   -- Reference
       S     (83),   -- Sample
       T     (84),   -- Training
       V     (86),   -- Developmental
       X     (88),   -- Exercise
       Z     (90),   -- "On the Air" Testing
       ... -- Expect additional key purpose values -- }

   Due to multiple layers of encapsulation or the use of content
   collections, the key-purpose attribute can appear in more than one
   location in the overall key package.  When there are multiple
   occurrences of the key-purpose attribute within the same scope, all
   fields within the attribute MUST contain exactly the same values.
   Receivers MUST reject any key package that fails these consistency
   checks.

12.  Key Use

   The key-use attribute specifies the intended use of the key material.
   It can appear as a symmetric key, symmetric key package, asymmetric,
   signed, authenticated, authenticated&unprotected, or content
   attribute.  If the key-use attribute appears as a signed,
   authenticated, authenticated&unprotected, or content attribute, then
   all of the keying material within the associated content MUST have
   the same key use value.

   The key-use attribute has the following syntax:

     aa-key-Use ATTRIBUTE ::= {
       TYPE KeyUse
       IDENTIFIED BY id-kma-keyUse }

     id-kma-keyUse OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 14 }

     KeyUse ::= ENUMERATED {
       n-a    (0),    -- Not applicable
       ffk    (1),    -- FIREFLY/CROSSTALK Key (Basic Format)
       kek    (2),    -- Key Encryption Key
       kpk    (3),    -- Key Production Key
       msk    (4),    -- Message Signature Key
       qkek   (5),    -- QUADRANT Key Encryption Key
       tek    (6),    -- Traffic Encryption Key
       tsk    (7),    -- Transmission Security Key
       trkek  (8),    -- Transfer Key Encryption Key
       nfk    (9),    -- Netted FIREFLY Key
       effk  (10),    -- FIREFLY Key (Enhanced Format)
       ebfk  (11),    -- FIREFLY Key (Enhanceable Basic Format)
       aek   (12),    -- Algorithm Encryption Key
       wod   (13),    -- Word of Day
       kesk (246),    -- Key Establishment Key
       eik  (247),    -- Entity Identification Key
       ask  (248),    -- Authority Signature Key
       kmk  (249),    -- Key Modifier Key
       rsk  (250),    -- Revocation Signature Key
       csk  (251),    -- Certificate Signature Key
       sak  (252),    -- Symmetric Authentication Key
       rgk  (253),    -- Random Generation Key
       cek  (254),    -- Certificate Encryption Key
       exk  (255),    -- Exclusion Key
       ... -- Expect additional key use values -- }

   The values for the key-use attribute have the following semantics:

      o  ffk: A FIREFLY/CROSSTALK key is used to establish a Key
         Establishment Key (KEK) or a Transmission Encryption Key (TEK)
         between two parties.  The KEK or TEK generated from the
         exchange is used with a symmetric encryption algorithm.  This
         key use value is associated with keys in the basic format.

      o  kek: A Key Encryption Key is used to encrypt or decrypt other
         keys for transmission or storage.

      o  kpk: A Key Production Key is used to initialize a keystream
         generator for the production of other electronically generated
         keys.

      o  msk: A Message Signature Key is used in a digital signature
         process that operates on a message to assure message source
         authentication, message integrity, and non-repudiation.

      o  qkek: QUADRANT Key Encryption Key is one part of a tamper-
         resistance solution.

      o  tek: A Traffic Encryption Key is used to encrypt plaintext, to
         superencrypt previously encrypted data, and/or to decrypt
         ciphertext.

      o  tsk: A Transmission Security Key is used to protect
         transmissions from interception and exploitation by means other
         than cryptanalysis.

      o  trkek: Transfer Key Encryption Key.  The keys used to protect
         communications with an intermediary.

      o  nfk: A Netted FIREFLY Key is a FIREFLY key that has an edition
         number associated with it.  When rekeyed, it is incremented,
         preventing communications with FIREFLY key of previous
         editions.  This edition number is maintained within a universal
         edition.

      o  effk: Enhanced FIREFLY Key is used to establish a KEK or a TEK
         between two parties.  The KEK or TEK generated from an exchange
         is used with a symmetric encryption algorithm.  This key use
         value is associated with keys in the enhanced format.

      o  ebfk: Enhanceable Basic FIREFLY Key is used to establish a KEK
         or a TEK between two parties.  The KEK or TEK generated from an
         exchange is used with a symmetric encryption algorithm.  This
         key use value is associated with keys in the enhanceable basic
         format.

      o  aek: An Algorithm Encryption Key is used to encrypt or decrypt
         an algorithm implementation as well as other functionality in
         the implementation.

      o  wod: A key used to generate the Word of the Day (WOD).

      o  kesk: A Key Establishment Key is an asymmetric key set (e.g.,
         public/private/parameters) used to enable the establishment of
         symmetric key(s) between entities.

      o  eik: An Entity Identification Key is an asymmetric key set
         (e.g., public/private/parameters) used to identify one entity
         to another for access control and other similar purposes.

      o  ask: An Authority Signature Key is an asymmetric key set (e.g.,
         public/private/parameters) used by designated authorities to
         sign objects such as Trust Anchor Management Protocol (TAMP)
         messages and firmware packages.

      o  kmk: A Key Modifier Key is a symmetric key used to modify the
         results of the process that forms a symmetric key from a public
         key exchange process.

      o  rsk: A Revocation Signature Key is an asymmetric key set (e.g.,
         public/private/parameters) used to sign and authenticate
         revocation lists and compromised key lists.

      o  csk: A Certificate Signature Key is an asymmetric key set
         (e.g., public/private/parameters) used to sign and authenticate
         public key certificates.

      o  sak: A Symmetric Authentication Key is used in a MAC algorithm
         to provide message integrity.  Differs from a Message Signature
         Key in that it is symmetric key material and it does not
         provide source authentication or non-repudiation.

      o  rgk: Random Generation Key is a key used to seed a
         deterministic pseudorandom number generator.

      o  cek: A Certificate Encryption Key is used to encrypt public key
         certificates to support privacy.

      o  exk: An Exclusion Key is a symmetric key used to
         cryptographically subdivide a single large security domain into
         smaller segregated domains.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-use attribute can appear in more than one
   location in the overall key package.  When there are multiple
   occurrences of the key-use attribute within the same scope, all
   fields within the attribute MUST contain exactly the same values.
   Receivers MUST reject any key package that fails these consistency
   checks.

13.  Transport Key

   The transport-key attribute identifies whether an asymmetric key is a
   transport key or an operational key (i.e., whether or not the key can
   be used as is).  It can appear as an asymmetric key, signed,
   authenticated, authenticated&unprotected, or content attribute.  If
   the transport-key attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, then all of the
   keying material within the associated content MUST have the same
   operational/transport key material.

     aa-transportKey ATTRIBUTE ::= {
       TYPE TransOp
       IDENTIFIED BY id-kma-transportKey }

     id-kma-transportKey OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 15 }

     TransOp ::= ENUMERATED {
       transport    (1),
       operational  (2) }

   Due to multiple layers of encapsulation or the use of content
   collections, the transport-key attribute can appear in more than one
   location in the overall key package.  When there are multiple
   occurrences of the transport-key attribute within the same scope, all
   fields within the attribute MUST contain exactly the same values.
   Receivers MUST reject any key package that fails these consistency
   checks.

14.  Key Distribution Period

   The key-distribution-period attribute indicates the period of time
   that the keying material is intended for distribution.  Keying
   material is often distributed before it is intended to be used.  Time

   of day must be represented in Coordinated Universal Time (UTC).  It
   can appear as a symmetric key, symmetric key package, asymmetric key,
   signed, authenticated, authenticated&unprotected, or content
   attribute.  If the key-distribution-period attribute appears as a
   signed, authenticated, authenticated&unprotected, or content
   attribute, then all of the keying material within the content MUST
   have the same key distribution period.

   The key-distribution-period attribute has the following syntax:

     aa-keyDistributionPeriod ATTRIBUTE ::= {
       TYPE KeyDistPeriod
       IDENTIFIED BY id-kma-keyDistPeriod }

     id-kma-keyDistPeriod OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 5 }

     KeyDistPeriod ::= SEQUENCE {
       doNotDistBefore  [0] BinaryTime OPTIONAL,
       doNotDistAfter       BinaryTime }

     BinaryTime ::= INTEGER

   The fields in the key-distribution-period attribute have the
   following semantics:

      o  The doNotDistBefore field is OPTIONAL, and when it is present,
         the keying material SHOULD NOT be distributed before the date
         and time provided.

      o  The doNotDistAfter field is REQUIRED, and the keying material
         SHOULD NOT be distributed after the date and time provided.

   When the key-distribution-period attribute is associated with a
   collection of keying material, the distribution period applies to all
   of the keys in the collection.  None of the keying material in the
   collection SHOULD be distributed outside the indicated period.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-distribution-period attribute can appear in more
   than one location in the overall key package.  When there are
   multiple occurrences of the key-distribution-period attribute within
   the same scope, all of the included attribute fields MUST contain
   exactly the same value.  However, if the doNotDistBefore field is
   absent in an inner layer, a value MAY appear in an outer layer
   because the outer layer constrains the inner layer.  Receivers MUST
   reject any key package that fails these consistency checks.

15.  Key Validity Period

   The key-validity-period attribute indicates the period of time that
   the keying material is intended for use.  Time of day MUST be
   represented in Coordinated Universal Time (UTC).  It can appear as a
   symmetric key, symmetric key package, asymmetric key, signed,
   authenticated, authenticated&unprotected, or content attribute.  If
   the key-validity-period attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, then all of the
   keying material within the content MUST have the same key validity
   period.

   The key-validity-period attribute has the following syntax:

     aa-keyValidityPeriod ATTRIBUTE ::= {
       TYPE KeyValidityPeriod
       IDENTIFIED BY id-kma-keyValidityPeriod }

     id-kma-keyValidityPeriod OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 6 }

     KeyValidityPeriod ::= SEQUENCE {
       doNotUseBefore      BinaryTime,
       doNotUseAfter       BinaryTime OPTIONAL }

     BinaryTime ::= INTEGER

   The fields in the key-validity-period attribute have the following
   semantics:

      o  The doNotUseBefore field is REQUIRED, and the keying material
         SHOULD NOT be used before the date and time provided.

      o  The doNotUseAfter field is OPTIONAL, and when it is present,
         the keying material SHOULD NOT be used after the date and time
         provided.

   For a key package that is being used for rekey, the doNotUseAfter
   field MAY be required by some templates even though the syntax is
   OPTIONAL.

   When the key-validity-period attribute is associated with a
   collection of keying material, the validity period applies to all of
   the keys in the collection.  None of the keying material in the
   collection SHOULD be used outside the indicated period.

   The key-validity-period attribute described in this section and the
   key-duration attribute described in the next section provide
   complementary functions.  The key-validity-period attribute provides
   explicit date and time values, which indicate the beginning and
   ending of the keying material usage period.  The key-duration
   attribute provides the maximum length of time that the keying
   material SHOULD be used.  If both attributes are provided, this
   duration MAY occur at any time within the specified period, but the
   limits imposed by both attributes SHOULD be honored.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-validity-period attribute can appear in more
   than one location in the overall key package.  When there are
   multiple occurrences of the key-validity-period attribute within the
   same scope, all of the included attribute fields MUST contain exactly
   the same value.  However, if the doNotUseAfter field is absent in an
   inner layer, a value MAY appear in an outer layer.  Receivers MUST
   reject any key package that fails these consistency checks.

16.  Key Duration

   The key-duration attribute indicates the maximum period of time that
   the keying material is intended for use.  The date and time that the
   duration begins is not specified, but the maximum amount of time that
   the keying material can be used to provide security services is
   specified.  It can appear as a symmetric key, symmetric key package,
   asymmetric key, signed, authenticated, authenticated&unprotected, or
   content attribute.  If the key-duration attribute appears as a
   signed, authenticated, authenticated&unprotected, or content
   attribute, then all of the keying material within the content MUST
   have the same key duration.

   The key-duration attribute has the following syntax:

     aa-keyDurationPeriod ATTRIBUTE ::= {
       TYPE KeyDuration
       IDENTIFIED BY id-kma-keyDuration }

     id-kma-keyDuration OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 7 }

     KeyDuration ::= CHOICE {
       hours      [0] INTEGER (1..ub-KeyDuration-hours),
       days           INTEGER (1..ub-KeyDuration-days),
       weeks      [1] INTEGER (1..ub-KeyDuration-weeks),
       months     [2] INTEGER (1..ub-KeyDuration-months),
       years      [3] INTEGER (1..ub-KeyDuration-years) }

     ub-KeyDuration-hours  INTEGER ::=  96
     ub-KeyDuration-days   INTEGER ::= 732
     ub-KeyDuration-weeks  INTEGER ::= 104
     ub-KeyDuration-months INTEGER ::=  72
     ub-KeyDuration-years  INTEGER ::= 100

   The key-validity-period attribute described in the previous section
   and the key-duration attribute described in this section provide a
   complementary function.  The relationship between these attributes is
   described in the previous section.

   Due to multiple layers of encapsulation or the use of content
   collections, the key-duration attribute can appear in more than one
   location in the overall key package.  When there are multiple
   occurrences of the key-duration attribute within the same scope, all
   of the included attribute fields MUST contain exactly the same value.
   Receivers MUST reject any key package that fails these consistency
   checks.

17.  Classification

   The classification attribute indicates level of classification.  The
   classification attribute specifies the aggregate classification of
   the package content.  It can appear as a symmetric key, symmetric key
   package, asymmetric key, signed, authenticated,
   authenticated&unprotected, or content attribute.  If the
   classification attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, then the value MUST
   represent the classification of all of the keying material within the
   content.  Encrypted layers MAY contain content at a higher
   classification that will be revealed once they are decrypted.  If the
   classification attribute is associated with a collection, then the
   sensitivity of all the data within the collection MUST be dominated
   by the classification carried in this attribute.

   The classification attribute makes use of the ESSSecurityLabel
   defined in Section 17.1 as well as [RFC2634] and [RFC5911].  The term
   "classification" is used in this document, but the term "security
   label" is used in [RFC2634].  The two terms have the same meaning.

   [RFC2634] and [RFC5911] specify an object identifier and syntax for
   the security label attribute.  The same values are used for the
   classification attribute:

     aa-classificationAttribute ATTRIBUTE ::= {
       TYPE Classification
       IDENTIFIED BY id-aa-KP-classification }

     id-aa-KP-classification OBJECT IDENTIFIER ::= id-aa-securityLabel

     -- id-aa-securityLabel OBJECT IDENTIFIER ::= {
     --  iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
     --   pkcs-9(9) smime(16) id-aa(2) 2 }

     Classification ::= ESSSecurityLabel

   The syntax of ESSSecurityLabel is not repeated here; however, see
   Section 17.1 for security label conventions that MUST be followed by
   implementations of this specification.  See [RFC2634] for a complete
   discussion of the semantics and syntax.

   When the classification attribute appears in more than one location
   in the overall key package, each occurrence is evaluated
   independently.  The content originator MUST ensure that the
   classification attribute represents the sensitivity of the plaintext
   within the content.  That is, the classification MUST dominate any
   other plaintext classification attribute value that is present
   elsewhere in the overall key package.  Note that the classification
   attribute value may exceed these other plaintext classification
   attribute values if the other attribute values within the SignerInfo,
   AuthEnvelopedData, or AuthenticatedData are themselves classified and
   warrant the higher-security label value.

   When the classification attribute appears in more than one location
   in the overall key package, each security label might be associated
   with a different security policy.  Content originators SHOULD avoid
   mixing multiple security policies in the same key package whenever
   possible, since this requires that receivers and intermediaries that
   check the classification attribute values include support for the
   union of the security policies that are present.  Failure to
   recognize an included security policy MUST result in rejection of the
   key package.

   Receivers MUST reject any key package that includes a classification
   for which the receiver's processing environment is not authorized.

17.1.  Security Label

   The ESSSecurityLabel ASN.1 type is used to represent the
   classification.  The ESSSecurityLabel is defined in Section 3.2 of
   [RFC2634].  The syntax definition is repeated here to facilitate
   discussion:

     ESSSecurityLabel ::= SET {
       security-policy-identifier SecurityPolicyIdentifier,
       security-classification    SecurityClassification OPTIONAL,
       privacy-mark               ESSPrivacyMark OPTIONAL,
       security-categories        SecurityCategories OPTIONAL }

     ESSPrivacyMark ::= CHOICE {
       pString      PrintableString (SIZE (1..ub-privacy-mark-length)),
       utf8String   UTF8String (SIZE (1..MAX)) }

   A security policy is a set of criteria for the provision of security
   services.  The security-policy-identifier, which is an object
   identifier, is used to identify the security policy associated with
   the security label.  It indicates the semantics of the other security
   label components.

   If the key package receiver does not recognize the object identifier
   in the security-policy-identifier field and the security label
   includes a security-categories field, then the key package contents
   MUST NOT be accepted and the enclosed keying material MUST NOT be
   used.  If the key package receiver does not recognize the object
   identifier in the security-policy-identifier field and the security
   label does not include a security-categories field, then the key
   package contents MAY be accepted only if the security-classification
   field is present and it contains a value from the basic hierarchy as
   described below.

   This specification defines the use of the SecurityClassification
   field exactly as is it specified in the 1988 edition of ITU-T
   Recommendation X.411 [X.411], which states in part:

      If present, a security-classification may have one of a
      hierarchical list of values.  The basic security-classification
      hierarchy is defined in this Recommendation, but the use of these
      values is defined by the security-policy in force.  Additional
      values of security-classification, and their position in the
      hierarchy, may also be defined by a security-policy as a local
      matter or by bilateral agreement.  The basic security-
      classification hierarchy is, in ascending order: unmarked,
      unclassified, restricted, confidential, secret, top-secret.

   Implementations MUST support the basic security classification
   hierarchy.  Such implementations MAY also support other security-
   classification values; however, the placement of additional values in
   the hierarchy MUST be specified by the security policy.

   Implementations MUST NOT make access control decisions based on the
   privacy-mark.  However, information in the privacy-mark can be
   displayed to human users by devices that have displays to do so.  The
   privacy-mark length MUST NOT exceed 128 characters.  The privacy-mark
   SHALL use the PrintableString choice if all of the characters in the
   privacy-mark are members of the printable string character set.

   If present, security-categories provide further granularity for the
   keying material.  The security policy in force indicates the
   permitted syntaxes of any entries in the set of security categories.
   At most, 64 security categories may be present.  The security-
   categories have ASN.1 type SecurityCategories and further
   SecurityCategory [RFC5912], which are both repeated here to
   facilitate discussion:

     SecurityCategories ::= SET SIZE (1..ub-security-categories) OF
                              SecurityCategory
                                {{SupportedSecurityCategories}}

     SecurityCategory {SECURITY-CATEGORY:Supported} ::= SEQUENCE {
         type      [0]  IMPLICIT SECURITY-CATEGORY.
                          &id({Supported}),
         value     [1]  EXPLICIT SECURITY-CATEGORY.
                          &Type({Supported}{@type})
     }

   Four security categories are defined and are referred to as the
   Restrictive Tag, the Enumerated Tag, the Permissive Tag, and the
   Informative Tag.  Only the Enumerated Tag and Informative Tag are
   permitted in the classification attribute.

   The Enumerated Tag is composed of one or more non-negative integers.
   Each non-negative integer represents a non-hierarchical security
   attribute that applies to the labeled content.  A security policy
   might define a large set of security categories attributes, but a
   particular key package generally contains only a few security
   categories attributes.  In this case, use of the integer
   representation is intended to minimize the size of the label.
   Security attributes enumerated by tags of this type could be
   restrictive (such as compartments) or permissive (such as release
   permissions).  Two object identifiers for the SecurityCategory type
   field have been defined, one for restrictive and one for permissive.
   The object identifiers are:

     id-enumeratedRestrictiveAttributes OBJECT IDENTIFIER ::= {
       2 16 840 1 101 2 1 8 3 4 }

     id-enumeratedPermissiveAttributes OBJECT IDENTIFIER ::= {
       2 16 840 1 101 2 1 8 3 1 }

   With both the restrictive and permissive security category types, the
   corresponding SecurityCategory value has the following ASN.1
   definition:

     EnumeratedTag ::= SEQUENCE {
       tagName          OBJECT IDENTIFIER,
       attributeList    SET OF SecurityAttribute }

     SecurityAttribute ::= INTEGER (0..MAX)

   Any security policy that makes use of security categories MUST assign
   object identifiers for each tagName, assign the set of integer values
   associated with each tagName, and specify the semantic meaning for
   each integer value.  Restrictive security attributes and permissive
   security attributes SHOULD be associated with different tagName
   object identifiers.

   The Informative Tag is composed of either a) one or more non-negative
   integers or b) a bit string.  Only the integer choice is allowed in
   this specification.  Each non-negative integer represents a non-
   hierarchical security attribute that applies to the labeled content.
   Use of the integer representation is intended to minimize the size of
   the label since a particular key package generally contains only a
   few security categories attributes, even though a security policy
   might define a large set of security categories attributes.  Security
   attributes enumerated by tags of this type are informative (i.e., no
   access control is performed).  One object identifier for the
   SecurityCategory type field has been defined and is as follows:

     id-informativeAttributes OBJECT IDENTIFIER ::= {
       2 16 840 1 101 2 1 8 3 3 }

   The corresponding SecurityCategory value has the following ASN.1
   definition:

     InformativeTag ::= SEQUENCE {
       tagName     OBJECT IDENTIFIER,
       attributes  FreeFormField }

     FreeFormField ::= CHOICE {
       bitSetAttributes    BIT STRING,
       securityAttributes  SET OF SecurityAttribute }

   Any security policy that makes use of security categories MUST assign
   object identifiers for each tagName, assign the set of integer values
   associated with each tagName, and specify the semantic meaning for
   each integer value.

18.  Split Identifier

   The key package originator may include a split-identifier attribute
   to designate that the keying material contains a split rather than a
   complete key.  It may appear as a symmetric and asymmetric key
   attribute.  The split-identifier attribute MUST NOT appear as a
   symmetric key package, signed, authenticated,
   authenticated&unprotected, or content attribute.  Split keys have two
   halves, which are called "A" and "B".  The split-identifier attribute
   indicates which half is included in the key package, and it
   optionally indicates the algorithm that is needed to combine the two
   halves.  The combine algorithm is OPTIONAL since each key algorithm
   has a default mechanism for this purpose, and the combine algorithm
   is present only if the default mechanism is not employed.

   The split-identifier attribute has the following syntax:

     aa-splitIdentifier ATTRIBUTE ::= {
       TYPE SplitID
       IDENTIFIED BY id-kma-splitID }

     id-kma-splitID OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 11 }

     SplitID ::= SEQUENCE {
       ENUMERATED { a(0), b(1) },
       combineAlg  AlgorithmIdentifier
                   {COMBINE-ALGORITHM, {CombineAlgorithms}} OPTIONAL }

   In most cases, the default combine algorithm will be employed; it
   makes this attribute a simple constant that identifies either the "A"
   or "B" half of the split key.  This supports implementation of some
   key distribution policies.

   Note that each split might have its own CRC, but the key and the
   check word are both recovered when the two splits are combined.

   Since the split-identifier attribute MUST NOT appear as a signed,
   authenticated, authenticated&unprotected, or content attribute, a key
   package cannot include multiple occurrences of the split-identifier

   attribute within the same scope.  Receivers MUST reject any key
   package in which the split-identifier attribute appears as a signed,
   authenticated, authenticated&unprotected, or content attribute.

19.  Key Package Type

   The key-package-type attribute is a shorthand method for specifying
   all aspects of the key package format, including which attributes are
   present and the structure of the encapsulated content or collection.
   The key-package-type attribute can be used as a signed,
   authenticated, authenticated&unprotected, or content attribute.

   Rather than implementing the full flexibility of this specification,
   some devices may implement support for one or more specific key
   package formats instantiating this specification.  Those specific
   formats are called templates and can be identified using a key-
   package-type attribute.

   The key-package-type attribute has the following syntax:

     aa-keyPackageType ATTRIBUTE ::= {
       TYPE KeyPkgType
       IDENTIFIED BY id-kma-keyPkgType }

     id-kma-keyPkgType OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 12 }

     KeyPkgType ::= OBJECT IDENTIFIER

   Due to multiple layers of encapsulation or the use of content
   collections, the key-package-type attribute can appear in more than
   one location in the overall key package.  When that happens, each
   occurrence is used independently.  Since the receiver is likely to
   use the key-package-type attribute value as a decoding aid, any error
   will most likely lead to parsing problems, and these problems could
   result in many different errors being reported.

20.  Signature Usage

   The signature-usage attribute identifies the CMS content types that
   this key can be used to sign, or that are permitted to be signed by
   the end-entity key in a cert path validated by this key.  Symmetric
   key packages do not contain signature generation or signature
   validation keying material, so the signature-usage attribute MUST NOT
   appear in a symmetric key package.  For an asymmetric key package,
   the signature-usage attribute indicates the kind of objects that are
   to be signed with the private key in the package.  However, if the

   asymmetric key package contains a Certificate Signature Key, then the
   signature-usage attribute also indicates what signed objects can be
   validated using certificates that are signed by the private key in
   the asymmetric key package.  Therefore, the signature-usage attribute
   also indicates what kind of objects can be signed by the private keys
   associated with these certificates.  The signature-usage attribute
   MUST NOT appear as a signed, authenticated,
   authenticated&unprotected, or content attribute.

   The signature-usage attribute has the following syntax:

     aa-signatureUsage-v3 ATTRIBUTE ::= {
       TYPE SignatureUsage
       IDENTIFIED BY id-kma-sigUsageV3 }

     id-kma-sigUsageV3 OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 22 }

     SignatureUsage ::= CMSContentConstraints

   The SignatureUsage structure has the same syntax as the
   CMSContentConstraints structure from [RFC6010], and it is repeated
   here for convenience.

     CMSContentConstraints ::= SEQUENCE SIZE (1..MAX) OF
                                ContentTypeConstraint

     ContentTypeGeneration ::= ENUMERATED  {
       canSource(0),
       cannotSource(1)}

     ContentTypeConstraint ::= SEQUENCE {
       contentType      CONTENT-TYPE.&id ({ContentSet|ct-Any,...}),
       canSource        ContentTypeGeneration DEFAULT canSource,
       attrConstraints  AttrConstraintList OPTIONAL }

     Constraint { ATTRIBUTE:ConstraintList } ::= SEQUENCE {
       attrType    ATTRIBUTE.&id({ConstraintList}),
       attrValues  SET SIZE (1..MAX) OF ATTRIBUTE.
                     &Type({ConstraintList}{@attrType})  }

     SupportedConstraints ATTRIBUTE ::= {SignedAttributesSet, ... }

     AttrConstraintList ::= SEQUENCE SIZE (1..MAX) OF
                            Constraint {{ SupportedConstraints }}

     NOTE: SignedAttributesSet is updated by this specification.

   The SignatureUsage contains a type of CMSContentConstraints.  One or
   more ContentTypeConstraint MUST appear in CMSContentConstraints.

   Within ContentTypeConstraint, the contentType field indicates the
   encapsulated content type identifier that can be signed with the
   signature key.  A particular content type MUST NOT appear more than
   once in the list.  The CMS protecting content types need not be
   included in the list of permitted content types as the use of CMS is
   always authorized (see [RFC6010]).

   Within ContentTypeConstraint, the canSource enumeration indicates
   whether the signature key can be used to directly sign the indicated
   content type.  If the ContentTypeConstraint is canSource (the default
   value), then the signature key can be used to directly sign the
   specified content type.  If the ContentTypeConstraint is
   cannotSource, then the signature key can only be used with the
   specified content type if it encapsulates a signature that was
   generated by an originator with a ContentTypeConstraint that is
   canSource.

   Within ContentTypeList, the attrConstraints OPTIONAL field contains a
   sequence of constraints specific to the content type.  If the
   attrConstraints field is absent, the signature key can be used to
   sign the specified content type, without any further checking.  If
   the attrConstraints field is present, then the signature key can only
   be used to sign the specified content type if all of the constraints
   for that content type are satisfied.  Content type constraints are
   checked by matching the attribute values in the attrConstraint field
   against the attribute value in the content.  The constraints succeed
   if the attribute is not present; they fail if the attribute is
   present and the value is not one of the values provided in
   attrConstraint.

   The fields of attrConstraints implement constraints specific to the
   content type.  The attrType field is an AttributeType, which is an
   object identifier of a signed attribute carried in the SignerInfo of
   the content.  The attrValues field provides one or more acceptable
   signed attribute values.  It is a set of AttributeValue.  For a
   signed content to satisfy the constraint, the SignerInfo MUST include
   a signed attribute of the type identified in the attrType field, and
   the signed attribute MUST contain one of the values in the set
   carried in attrValues.

   Since the signature-usage attribute MUST NOT appear as a signed,
   authenticated, authenticated&unprotected, or content attribute, an
   asymmetric key package cannot include multiple occurrences of the
   signature-usage attribute within the same scope.  Receivers MUST

   reject any asymmetric key package in which the signature-usage
   attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute.

21.  Other Certificate Format

   The other-certificate-formats attribute specifies the type, format,
   and value of certificates that are not X.509 public key certificates.
   Symmetric key packages do not contain any certificates, so the other-
   certificate-formats attribute MUST NOT appear in a symmetric key
   package.  It SHOULD appear in the attributes field, when the
   publicKey field is absent and the certificate format is not X.509.
   This attribute MUST NOT appear in an attributes field that includes
   the user-certificate attribute from Section 8.  The other-
   certificate-formats attribute MUST NOT appear as a signed,
   authenticated, authenticated&unprotected, or content attribute.

   The other-certificate-formats attribute has the following syntax:

     aa-otherCertificateFormats ATTRIBUTE ::= {
       TYPE CertificateChoices
       IDENTIFIED BY id-kma-otherCertFormats }

     id-kma-otherCertFormats OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 19 }

     CertificateChoices ::= CHOICE {
       certificate             Certificate,
       extendedCertificate [0] IMPLICIT ExtendedCertificate,
                                        -- Obsolete
       v1AttrCert          [1] IMPLICIT AttributeCertificateV1,
                                        -- Obsolete
       v2AttrCert          [2] IMPLICIT AttributeCertificateV2,
       other               [3] IMPLICIT OtherCertificateFormat }

     OtherCertificateFormat ::= SEQUENCE {
       otherCertFormat           OBJECT IDENTIFIER,
       otherCert ANY DEFINED BY  otherCertFormat }

   The other-certificate-formats attribute makes use of the
   CertificateChoices field defined in Section 10.2.2 of [RFC5652].  The
   certificate, extendedCertificate, and v1AttrCert fields MUST be
   omitted.  The v2AttrCert field can include Version 2 Attribute
   Certificates.  The other field can include Enhanced FIREFLY
   certificates and other as yet undefined certificate formats.

   Since the other-certificate-formats attribute MUST NOT appear as a
   signed, authenticated, authenticated&unprotected, or content
   attribute, an asymmetric key package cannot include multiple
   occurrences of the other-certificate-formats attribute within the
   same scope.  Receivers MUST reject any asymmetric key package in
   which the other-certificate-formats attribute appears as a signed,
   authenticated, authenticated&unprotected, or content attribute.

22.  PKI Path

   The pki-path attribute includes certificates that can aid in the
   validation of the certificate carried in the user-certificate
   attribute.  Symmetric key packages do not contain any certificates,
   so the pkiPath attribute MUST NOT appear in a symmetric key package.
   It can appear as an asymmetric key, signed, authenticated,
   authenticated&unprotected, or content attribute.  It can appear in
   the attributes field, when the publicKey field is absent and the
   certificate format is X.509.  This attribute MUST NOT appear in an
   AsymmetricKeyPackage that has an other-certificate-formats attribute
   in the attributes field.  If the pki-path attribute appears as a
   signed, authenticated, authenticated&unprotected, or content
   attribute, then the value includes certificates that can be used to
   construct a certification path to all of the keying material within
   the content.  This attribute MUST be supported.

   The syntax is taken from [X.509] but redefined using the ATTRIBUTE
   CLASS from [RFC5912].  The pki-path attribute has the following
   syntax:

     aa-pkiPath ATTRIBUTE ::= {
       TYPE PkiPath
       IDENTIFIED BY id-at-pkiPath }

     id-at-pkiPath OBJECT IDENTIFIER ::= {
      joint-iso-itu-t(2) ds(5) attributes(4) 70 }

     PkiPath ::= SEQUENCE SIZE (1..MAX) OF Certificate

   The first certificate in the sequence is the subject's parent
   Certification Authority (CA).  The next certificate is that CA's
   parent, and so on.  The end-entity and trust anchor are not included
   in this attribute.

   Due to multiple layers of encapsulation or the use of content
   collections, the pki-path attribute can appear in more than one
   location in the overall key package.  When that happens, each
   occurrence is evaluated independently.

23.  Useful Certificates

   The useful-certificates attribute includes certificates that can aid
   in the validation of certificates associated with other parties with
   whom secure communications are anticipated.  It can appear as an
   asymmetric key, signed, authenticated, authenticated&unprotected, or
   content attribute.  For an asymmetric key that has an other-
   certificate-formats attribute (Section 21) in the attributes field,
   the useful-certificates attribute MUST NOT appear.  If the useful-
   certificates attribute appears as a signed, authenticated,
   authenticated&unprotected, or content attribute, then the value
   includes certificates that may be used to validate certificates of
   others with whom the receiver communicates.  This attribute MUST be
   supported.

   The useful-certificates attribute has the following syntax:

     aa-usefulCertificates ATTRIBUTE ::= {
       TYPE CertificateSet
       IDENTIFIED BY id-kma-usefulCerts }

     id-kma-usefulCerts OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 20 }

     CertificateSet ::= SET OF CertificateChoices

   The useful-certificates attribute makes use of the CertificateSet
   field defined in Section 10.2.3 of [RFC5652].  Within the
   CertificateChoices field, the extendedCertificate and v1AttrCert
   fields MUST always be omitted.  If the userCertificate attribute from
   Section 8 is included, the other field MUST NOT be present.  If the
   other-certificate-formats attribute (Section 21) is included, the
   certificate field MUST NOT be present.

   Due to multiple layers of encapsulation or the use of content
   collections, the useful-certificates attribute can appear in more
   than one location in the overall key package.  When the useful-
   certificates attribute appears in more than one location in the
   overall key package, each occurrence is evaluated independently.

24.  Key Wrap Algorithm

   The key-wrap-algorithm attribute identifies a key wrap algorithm with
   an algorithm identifier.  It can appear as a symmetric key or
   symmetric key package attribute.  When this attribute is present in
   sKeyAttrs, it indicates that the associated sKey field contains a
   black key, which is an encrypted key, that was wrapped by the

   identified algorithm.  When this attribute is present in
   sKeyPkgAttrs, it indicates that every sKey field in that symmetric
   key package contains a black key and that all keys are wrapped by the
   same designated algorithm.

   The key-wrap-algorithm attribute has the following syntax:

     aa-keyWrapAlgorithm ATTRIBUTE ::= {
       TYPE AlgorithmIdentifier{KEY-WRAP, {KeyEncryptionAlgorithmSet}}
       IDENTIFIED BY id-kma-keyWrapAlgorithm }

     id-kma-keyWrapAlgorithm OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 21 }

     KeyEncryptionAlgorithmSet KEY-WRAP ::= { ... }

25.  Content Decryption Key Identifier

   The content-decryption-key-identifier attribute can appear as an
   unprotected attribute as well as a symmetric and symmetric key
   package attribute.  The attribute's semantics differ based on the
   location.

25.1.  Content Decryption Key Identifier: Symmetric Key and Symmetric
       Key Package

   The content-decryption-key-identifier attribute [RFC6032] identifies
   the keying material needed to decrypt the sKey.  It can appear as a
   symmetric key and symmetric key package attribute.  If the key-wrap-
   algorithm attribute appears in sKeyPkgAttrs, then the corresponding
   content-decryption-identifier attribute can appear in either
   sKeyPkgAttrs or sKeyAttrs.  If the key-wrap-algorithm attribute
   (Section 24) appears in sKeyAttrs, then the corresponding content-
   decryption-identifier attribute MUST appear in sKeyAttrs.

   The content-decryption-key-identifier attribute in included for
   convenience:

     aa-contentDecryptKeyIdentifier ATTRIBUTE ::= {
       TYPE ContentDecryptKeyID
       IDENTIFIED BY id-aa-KP-contentDecryptKeyID }

     id-aa-KP-contentDecryptKeyID OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes(5) 66 }

     ContentDecryptKeyID ::= OCTET STRING

   The content decryption key identifier contains an octet string, and
   this syntax does not impose any particular structure on the
   identifier value.

25.2.  Content Decryption Key Identifier: Unprotected

   The content-decryption-key-identifier attribute can be used to
   identify the keying material that is needed for decryption of the
   EncryptedData content if there is any ambiguity.

   The content-decryption-key-identifier attribute syntax is found in
   Section 25.1.  The content decryption key identifier contains an
   octet string, and this syntax does not impose any particular
   structure on the identifier value.

   Due to multiple layers of encryption, the content-decryption-key-
   identifier attribute can appear in more than one location in the
   overall key package.  When that happens, each occurrence is evaluated
   independently.  Each one is used to identify the needed keying
   material for that layer of encryption.

26.  Certificate Pointers

   The certificate-pointers attribute can be used to reference one or
   more certificates that may be helpful in the processing of the
   content once it is decrypted.  Sometimes certificates are omitted if
   they can be easily fetched.  However, an intermediary may have better
   facilities to perform the fetching than the receiver.  The
   certificate-pointers attribute may be useful in some environments.
   This attribute can appear as an unprotected and an
   unauthenticated&unprotected attribute.

   The certificate-pointers attribute uses the same syntax and semantics
   as the subject information access certificate extension [RFC5280].
   The certificate-pointers attribute has the following syntax:

     aa-certificatePointers ATTRIBUTE ::= {
       TYPE SubjectInfoAccessSyntax
       IDENTIFIED BY id-pe-subjectInfoAccess }

     id-pe-subjectInfoAccess OBJECT IDENTIFIER ::= {
       iso(1) identified-organization(3) dod(6) internet(1)
       security(5) mechanisms(5) pkix(7) pe(1) 11 }

     SubjectInfoAccessSyntax ::= SEQUENCE SIZE (1..MAX) OF
                                   AccessDescription

     AccessDescription ::= SEQUENCE {
       accessMethod       OBJECT IDENTIFIER,
       accessLocation     GeneralName }

   As specified in [RFC5280], the id-ad-caRepository access method can
   be used to point to a repository where a Certification Authority
   publishes certificates and Certificate Revocation Lists (CRLs).  In
   this case, the accessLocation field tells how to access the
   repository.  Where the information is available via HTTP, FTP, or the
   Lightweight Directory Access Protocol (LDAP), accessLocation contains
   a Uniform Resource Identifier (URI).  Where the information is
   available via the Directory Access Protocol (DAP), accessLocation
   contains a directory name.

27.  CRL Pointers

   The CRL-pointers attribute can be used to reference one or more CRLs
   that may be helpful in the processing of the content once it is
   decrypted.  Sometimes CRLs are omitted to conserve space or to ensure
   that the most recent CRL is obtained when the certificate is
   validated.  However, an intermediary may have better facilities to
   perform the fetching than the receiver.  The CRL-pointers attribute
   may be useful in some environments.  This attribute can appear as an
   unprotected and unauthenticated&unprotected attribute.

   The CRL-pointers attribute has the following syntax:

     aa-crlPointers ATTRIBUTE ::= {
       TYPE GeneralNames
       IDENTIFIED BY id-aa-KP-crlPointers }

     id-aa-KP-crlPointers OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes(5) 70 }

   The CRL-pointers attribute uses the GeneralNames syntax from
   [RFC5280].  Each name describes a different mechanism to obtain the
   same CRL.  Where the information is available via HTTP, FTP, or LDAP,
   GeneralNames contains a URI.  Where the information is available via
   DAP, GeneralNames contains a directory name.

28.  Key Package Identifier and Receipt Request

   The key-package-identifier-and-receipt-request attribute from
   [RFC7191] is also supported.  It can appear as a signed attribute,
   authenticated, authenticated&unprotected, or content attribute.

29.  Additional Error Codes

   This specification also defines three additional extended
   ErrorCodeChoice object identifiers for the oid field [RFC7191]:

     id-errorCodes OBJECT IDENTIFIER ::= {
       joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) errorCodes(22) }

     id-missingKeyType OBJECT IDENTIFIER ::= {
       id-errorCodes 1 }

     id-privacyMarkTooLong OBJECT IDENTIFIER ::= {
       id-errorCodes 2 }

     id-unrecognizedSecurityPolicy OBJECT IDENTIFIER ::= {
       id-errorCodes 3 }

     id-incorrectKeyProvince OBJECT IDENTIFIER ::= {
       id-errorCodes 4 }

   missingKeyType indicates that all keying material within a package is
   of the same type; however, the key-package-type attribute is not
   specified in sKeyPkgAttrs [RFC6031].

   privacyMarkTooLong indicates that a classification attribute includes
   a privacy-mark that exceeds 128 characters in length.

   unrecognizedSecurityPolicy indicates that a security-policy-
   identifier is not supported.

   incorrectKeyProvince indicates that the value of the key-province-v2
   attribute in a key package does not match the key province constraint
   of the trust anchor used to validate the key package.

30.  Processing Key Package Attribute Values and CMS Content Constraints

   Trust anchors may contain constraints for any content type [RFC5934].
   When the trust anchor contains constraints for the symmetric key
   package content type or the asymmetric key package content type, then
   the constraints provide default values for key package attributes
   that are not present in the key package and define the set of
   acceptable values for key package attributes that are present.

   When a trust anchor delegates authority by issuing an X.509
   certificate, the CMS content constraints certificate extension
   [RFC6010] may be included to constrain the authorizations.  The trust

   anchor and the X.509 certification path provide default values for
   key package attributes that are not present in the key package and
   define the set of acceptable of values for key package attributes
   that are present.

   Constraints on content type usage are represented as attributes.

   The processing procedures for the CMS content constraints certificate
   extension [RFC6010] are part of the validation of a signed or
   authenticated object, and the procedures yield three output values:
   cms_constraints, cms_effective_attributes, and
   cms_default_attributes.  Object validation MUST be performed before
   processing the key package contents, and these output values are used
   as part of key package processing.  These same output values are
   easily generated directly from a trust anchor and the key package
   when no X.509 certification path is involved in validation.

   The cms_effective_attributes provides the set of acceptable values
   for attributes.  Each attribute present in the key package that
   corresponds to an entry in cms_effective_attributes MUST contain a
   value that appears in cms_effective_attributes entry.  Attributes
   that do not correspond to an entry in cms_effective_attributes are
   unconstrained and may contain any value.  Correspondence between
   attributes and cms_effective_attributes is determined by comparing
   the attribute object identifier to object identifier for each entry
   in cms_effective_attributes.

   The cms_default_attributes provides values for attributes that do not
   appear in the key package.  If cms_default_attributes includes only
   one attribute value for a particular attribute, then that value is
   used as if it were included in the key package itself.  However, if
   cms_default_attributes includes more than one value for a particular
   attribute, then the appropriate value remains ambiguous and the key
   package should be rejected.

   Some attributes can appear in more than one place in the key package,
   and for this reason, the attribute definitions include consistency
   checks.  These checks are independent of constraints checking.  In
   addition to the consistency checks, each instance of the attribute
   MUST be checked against the set of cms_effective_attributes, and the
   key package MUST be rejected if any of the attributes values are not
   in the set of authorized set of values.

31.  Attribute Scope

   This section provides an example symmetric key package in order to
   provide a discussion of the scope of attributes.  This is an
   informative section; it is not a normative portion of this
   specification.  Figure 1 provides the example.  All of the concepts
   apply to either a symmetric key package or an asymmetric key package,
   with the exception of the key-algorithm attribute, which is only
   applicable to a symmetric key package.  Each of the components is
   labeled with a number inside parentheses for easy reference:

      (1) is the ContentInfo that must be present as the outermost layer
          of encapsulation.  It contains no attributes.  It is shown for
          completeness.

      (2) is a SignedData content type, which includes six signed
          attributes.  Four of the signed attributes are keying material
          attributes.

      (3) is a ContentCollection that includes two encapsulated content
          types: a ContentWithAttributes and an EncryptedKeyPackage.
          This content type does not provide any attributes.

      (4) is a ContentWithAttributes content type.  It encapsulates a
          SignedData content type.  Four key material attributes are
          provided.

      (5) is a SignedData content type.  It encapsulates a
          SymmetricKeyPackage content type.  Six signed attributes are
          provided.  Four attributes are key material attributes.

      (6) is a SymmetricKeyPackage content type, and it includes three
          key material attributes.  Note that the contents of this key
          package are not encrypted, but the contents are covered by two
          digital signatures.

      (7) is an EncryptedKeyPackage content type.  It encapsulates a
          SignedData content type.  This content type provides one
          unprotected attribute.

      (8) is a SignedData content type.  It encapsulates a
          SymmetricKeyPackage content type.  Six signed attributes are
          provided.  Four attributes are key material attributes.

      (9) is a SymmetricKeyPackage content type, and it includes three
          key material attributes.  Note that the contents of this key
          package are encrypted; the plaintext keying material is
          covered by one digital signature, and the ciphertext keying
          material is covered by another digital signature.

   SignedData content type (2) includes six signed attributes:

      o  The content-type attribute contains id-ct-contentCollection to
         indicate the type of the encapsulated content, and it has no
         further scope.

      o  The message-digest attribute contains the one-way hash value of
         the encapsulated content; it is needed to validate the digital
         signature.  It has no further scope.

      o  The classification attribute contains the security label for
         all of the plaintext in the encapsulated content.  Each
         classification attribute is evaluated separately; it has no
         further scope.  In general, the values of this attribute will
         match or dominate the security label values in (4), (5), and
         (6).  The value of this attribute might not match or dominate
         the security label values in (8) and (9) since they are
         encrypted.  It is possible that these various security label
         values are associated with different security policies.  To
         avoid the processing complexity associated with policy mapping,
         comparison is not required.

      o  The key-package-receivers-v2 attribute indicates the authorized
         key package receivers, and it has no further scope.  The
         additional instances of key-package-receivers-v2 attribute
         embedded in (4) are evaluated without regard to the value of
         the instance in (2).

      o  The key-distribution-period attribute contains two date values:
         doNotDistBefore and doNotDistAfter.  These values must match
         all others within the same scope, which in this example is the
         key-distribution-period within (4).

      o  The key-package-type attributes indicates the format of the key
         package, and it has no further scope.  The key-package-type
         attributes values within (5) and (8) are evaluated without
         regard to the value of this attribute.

   ContentWithAttributes content type (4) includes four attributes:

      o  The classification attribute contains the security label for
         all of the plaintext in the encapsulated content.  Each
         classification attribute is evaluated separately; it has no
         further scope.

      o  The TSEC-Nomenclature attribute includes only the shortTitle
         field, and the value must match all other instances within the
         same scope, which appear in (5) and (6).  Note that the TSEC-
         Nomenclature attribute values in (8) and (9) are not in the
         same scope as the TSEC-Nomenclature attribute that appears in
         (4).

      o  The key-package-receivers-v2 attribute indicates the authorized
         key package receivers, and it has no further scope.  The
         enveloping instance of key-package-receivers-v2 attribute value
         in (2) is evaluated without regard to the value of this
         instance in (4), and has no effect on the value of this
         instance in (4).

      o  The key-distribution-period attribute contains two date values:
         doNotDistBefore and doNotDistAfter.  These values must match
         all others within the same scope, which in this example is the
         key-distribution-period within (2).

   SignedData content type (5) includes six signed attributes:

      o  The content-type attribute contains id-ct-KP-skeyPackage to
         indicate the type of the encapsulated content, and it has no
         further scope.

      o  The message-digest attribute contains the one-way hash value of
         the encapsulated content; it is needed to validate the digital
         signature.  It has no further scope.

      o  The classification attribute contains the security label for
         all of the plaintext in the encapsulated content.  Each
         classification attribute is evaluated separately; it has no
         further scope.

      o  The TSEC-Nomenclature attribute includes only the shortTitle
         field, and the value must match all other instances within the
         same scope, which appear in (6).  Since this is within the
         scope of (4), these shortTitle field values must match as well.
         Note that the TSEC-Nomenclature attribute values in (8) and (9)
         are not in the same scope.

      o  The key-purpose attribute specifies the purpose of the key
         material.  All occurrences within the scope must have the same
         value; however, in this example, there are no other occurrences
         within the scope.  The key-purpose attribute value within (8)
         is evaluated without regard to the value of this attribute.

      o  The key-package-type attribute indicates the format of the key
         package, and it has no further scope.  The key-package-type
         attribute values within (2) and (8) are evaluated without
         regard to the value of this attribute.

   SymmetricKeyPackage content type (6) includes three keying material
   attributes, which could appear in the sKeyPkgAttrs or sKeyAttrs
   fields:

      o  The key-algorithm attribute includes only the keyAlg field, and
         it must match all other occurrences within the same scope.
         However, there are no other key-algorithm attribute occurrences
         in the same scope; the key-algorithm attribute value in (9) is
         not in the same scope.

      o  The classification attribute contains the security label for
         all of the plaintext in the key package.  Each classification
         attribute is evaluated separately; it has no further scope.

      o  The TSEC-Nomenclature attribute includes the shortTitle field
         as well as some of the optional fields.  The shortTitle field
         value must match the values in (4) and (5), since this content
         type is within their scope.  Note that the TSEC-Nomenclature
         attribute values in (8) and (9) are not in the same scope.

   EncryptedKeyPackage content type (7) includes one unprotected
   attribute, and the encryption will prevent any intermediary that does
   not have the ability to decrypt the content from making any
   consistency checks on (8) and (9):

      o  The content-decryption-key-identifier attribute identifies the
         key that is needed to decrypt the encapsulated content; it has
         no further scope.

   SignedData content type (8) includes six signed attributes:

      o  The content-type attribute contains id-ct-KP-skeyPackage to
         indicate the type of the encapsulated content, and it has no
         further scope.

      o  The message-digest attribute contains the one-way hash value of
         the encapsulated content; it is needed to validate the digital
         signature.  It has no further scope.

      o  The classification attribute contains the security label for
         content.  Each classification attribute is evaluated
         separately; it has no further scope.

      o  The TSEC-Nomenclature attribute includes only the shortTitle
         field, and the value must match all other instances within the
         same scope, which appear in (9).  Note that the TSEC-
         Nomenclature attribute values in (4), (5), and (6) are not in
         the same scope.

      o  The key-purpose attribute specifies the purpose of the key
         material.  All occurrences within the scope must have the same
         value; however, in this example, there are no other occurrences
         within the scope.  The key-purpose attribute value within (5)
         is evaluated without regard to the value of this attribute.

      o  The key-package-type attribute indicates the format of the key
         package, and it has no further scope.  The key-package-type
         attribute values within (2) and (5) are evaluated without
         regard to the value of this attribute.

   SymmetricKeyPackage content type (9) includes three keying material
   attributes, which could appear in the sKeyPkgAttrs or sKeyAttrs
   fields:

      o  The key-algorithm attribute includes only the keyAlg field, and
         it must match all other occurrences within the same scope.
         However, there are no other key-algorithm attribute occurrences
         in the same scope; the key-algorithm attribute value in (6) is
         not in the same scope.

      o  The classification attribute contains the security label for
         all of the plaintext in the key package.  Each classification
         attribute is evaluated separately; it has no further scope.

      o  The TSEC-Nomenclature attribute includes the shortTitle field
         as well as some of the optional fields.  The shortTitle field
         value must match the values in (8), since this content type is
         within its scope.  Note that the TSEC-Nomenclature attributes
         values in (4), (5), and (6) are not in the same scope.

   In summary, the scope of an attribute includes the encapsulated
   content of the CMS content type in which it appears, and some
   attributes also require consistency checks with other instances that
   appear within the encapsulated content.  Proper recognition of scope
   is required to accurately perform attribute processing.

   +------------------------------------------------------------------+
   | ContentInfo (1)                                                  |
   |+----------------------------------------------------------------+|
   || SignedData (2)                                                 ||
   ||+--------------------------------------------------------------+||
   ||| ContentCollection (3)                                        |||
   |||+-----------------------------++-----------------------------+|||
   |||| ContentWithAttributes (4)   || EncryptedKeyPackage (7)     ||||
   ||||+---------------------------+||+---------------------------+||||
   ||||| SignedData (5)            |||| SignedData (8)            |||||
   |||||+-------------------------+||||+-------------------------+|||||
   |||||| SymmetricKeyPackage (6) |||||| SymmetricKeyPackage (9) ||||||
   |||||| Attributes:             |||||| Attributes:             ||||||
   ||||||  Key Algorithm          ||||||  Key Algorithm          ||||||
   ||||||  Classification         ||||||  Classification         ||||||
   ||||||  TSEC-Nomenclature      ||||||  TSEC-Nomenclature      ||||||
   |||||+-------------------------+||||+-------------------------+|||||
   ||||| Attributes:               |||| Attributes:               |||||
   |||||  Content Type             ||||  Content Type             |||||
   |||||  Message Digest           ||||  Message Digest           |||||
   |||||  Classification           ||||  Classification           |||||
   |||||  TSEC-Nomenclature        ||||  TSEC-Nomenclature        |||||
   |||||  Key Purpose              ||||  Key Purpose              |||||
   |||||  Key Package Type         ||||  Key Package Type         |||||
   ||||+-------------------------- +||+---------------------------+||||
   |||| Attributes:                 || Unprotect Attributes:       ||||
   ||||  Classification             ||  Content Decrypt Key ID     ||||
   ||||  TSEC-Nomenclature          |+-----------------------------+|||
   ||||  Key Package Receivers      |                               |||
   ||||  Key Distribution Period    |                               |||
   |||+-----------------------------+                               |||
   ||+--------------------------------------------------------------+||
   || Attributes:                                                    ||
   ||  Content Type                                                  ||
   ||  Message Digest                                                ||
   ||  Classification                                                ||
   ||  Key Package Receivers                                         ||
   ||  Key Distribution Period                                       ||
   ||  Key Package Type                                              ||
   |+----------------------------------------------------------------+|
   +------------------------------------------------------------------+

            Figure 1: Example Illustrating Scope of Attributes

32.  Security Considerations

   The majority of this specification is devoted to the syntax and
   semantics of key package attributes.  It relies on other
   specifications, especially [RFC2634], [RFC4073], [RFC4108],
   [RFC5652], [RFC5911], [RFC5912], [RFC5958], [RFC6010], and [RFC6031];
   their security considerations apply here.  Additionally,
   cryptographic algorithms are used with CMS protecting content types
   as specified in [RFC5959], [RFC6160], [RFC6161], and [RFC6162]; the
   security considerations from those documents apply here as well.

   This specification also relies upon [RFC5280] for the syntax and
   semantics of X.509 certificates.  Digital signatures provide data
   integrity or data origin authentication, and encryption provides
   confidentiality.

   Security factors outside the scope of this specification greatly
   affect the assurance provided.  The procedures used by Certification
   Authorities (CAs) to validate the binding of the subject identity to
   their public key greatly affect the assurance that ought to be placed
   in the certificate.  This is particularly important when issuing
   certificates to other CAs.

   The CMS AuthenticatedData content type MUST be used with care since a
   Message Authentication Code (MAC) is used.  The same key is needed to
   generate the MAC or validate the MAC.  Thus, any party with access to
   the key needed to validate the MAC can generate a replacement that
   will be acceptable to other recipients.

   In some situations, returning very detailed error information can
   provide an attacker with insight into the security processing.  Where
   this is a concern, the implementation should return the most generic
   error code that is appropriate.  However, detailed error codes are
   very helpful during development, debugging, and interoperability
   testing.  For this reason, implementations may want to have a way to
   configure the use of generic or detailed error codes.

33.  References

33.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2634]  Hoffman, P., Ed., "Enhanced Security Services for S/MIME",
              RFC 2634, DOI 10.17487/RFC2634, June 1999,
              <http://www.rfc-editor.org/info/rfc2634>.

   [RFC4073]  Housley, R., "Protecting Multiple Contents with the
              Cryptographic Message Syntax (CMS)", RFC 4073,
              DOI 10.17487/RFC4073, May 2005,
              <http://www.rfc-editor.org/info/rfc4073>.

   [RFC4108]  Housley, R., "Using Cryptographic Message Syntax (CMS) to
              Protect Firmware Packages", RFC 4108,
              DOI 10.17487/RFC4108, August 2005,
              <http://www.rfc-editor.org/info/rfc4108>.

   [RFC5083]  Housley, R., "Cryptographic Message Syntax (CMS)
              Authenticated-Enveloped-Data Content Type", RFC 5083,
              DOI 10.17487/RFC5083, November 2007,
              <http://www.rfc-editor.org/info/rfc5083>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <http://www.rfc-editor.org/info/rfc5280>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <http://www.rfc-editor.org/info/rfc5652>.

   [RFC5911]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for
              Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
              DOI 10.17487/RFC5911, June 2010,
              <http://www.rfc-editor.org/info/rfc5911>.

   [RFC5912]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
              Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
              DOI 10.17487/RFC5912, June 2010,
              <http://www.rfc-editor.org/info/rfc5912>.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <http://www.rfc-editor.org/info/rfc5958>.

   [RFC5959]  Turner, S., "Algorithms for Asymmetric Key Package Content
              Type", RFC 5959, DOI 10.17487/RFC5959, August 2010,
              <http://www.rfc-editor.org/info/rfc5959>.

   [RFC6010]  Housley, R., Ashmore, S., and C. Wallace, "Cryptographic
              Message Syntax (CMS) Content Constraints Extension",
              RFC 6010, DOI 10.17487/RFC6010, September 2010,
              <http://www.rfc-editor.org/info/rfc6010>.

   [RFC6019]  Housley, R., "BinaryTime: An Alternate Format for
              Representing Date and Time in ASN.1", RFC 6019,
              DOI 10.17487/RFC6019, September 2010,
              <http://www.rfc-editor.org/info/rfc6019>.

   [RFC6031]  Turner, S. and R. Housley, "Cryptographic Message Syntax
              (CMS) Symmetric Key Package Content Type", RFC 6031,
              DOI 10.17487/RFC6031, December 2010,
              <http://www.rfc-editor.org/info/rfc6031>.

   [RFC6032]  Turner, S. and R. Housley, "Cryptographic Message Syntax
              (CMS) Encrypted Key Package Content Type", RFC 6032,
              DOI 10.17487/RFC6032, December 2010,
              <http://www.rfc-editor.org/info/rfc6032>.

   [RFC6160]  Turner, S., "Algorithms for Cryptographic Message Syntax
              (CMS) Protection of Symmetric Key Package Content Types",
              RFC 6160, DOI 10.17487/RFC6160, April 2011,
              <http://www.rfc-editor.org/info/rfc6160>.

   [RFC6162]  Turner, S., "Elliptic Curve Algorithms for Cryptographic
              Message Syntax (CMS) Asymmetric Key Package Content Type",
              RFC 6162, DOI 10.17487/RFC6162, April 2011,
              <http://www.rfc-editor.org/info/rfc6162>.

   [RFC6268]  Schaad, J. and S. Turner, "Additional New ASN.1 Modules
              for the Cryptographic Message Syntax (CMS) and the Public
              Key Infrastructure Using X.509 (PKIX)", RFC 6268,
              DOI 10.17487/RFC6268, July 2011,
              <http://www.rfc-editor.org/info/rfc6268>.

   [RFC7191]  Housley, R., "Cryptographic Message Syntax (CMS) Key
              Package Receipt and Error Content Types", RFC 7191,
              DOI 10.17487/RFC7191, April 2014,
              <http://www.rfc-editor.org/info/rfc7191>.

   [X.509]    ITU-T, "Information technology - Open Systems
              Interconnection - The Directory: Public-key and attribute
              certificate frameworks", ITU-T Recommendation X.509 |
              ISO/IEC 9594-8:2005, 2005.

   [X.680]    ITU-T, "Information Technology - Abstract Syntax Notation
              One", ITU-T Recommendation X.680 | ISO/IEC 8824-1:2002,
              2002.

   [X.681]    ITU-T, "Information Technology - Abstract Syntax Notation
              One: Information Object Specification", ITU-T
              Recommendation X.681 | ISO/IEC 8824-2:2002, 2002.

   [X.682]    ITU-T, "Information Technology - Abstract Syntax Notation
              One: Constraint Specification", ITU-T Recommendation X.682
              | ISO/IEC 8824-3:2002, 2002.

   [X.683]    ITU-T, "Information Technology - Abstract Syntax Notation
              One: Parameterization of ASN.1 Specifications", ITU-T
              Recommendation X.683 | ISO/IEC 8824-4:2002, 2002.

   [X.690]    ITU-T, "Information Technology - ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER)", ITU-T Recommendation X.690 | ISO/IEC 8825-1:2002,
              2002.

33.2.  Informative References

   [RFC5934]  Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor
              Management Protocol (TAMP)", RFC 5934,
              DOI 10.17487/RFC5934, August 2010,
              <http://www.rfc-editor.org/info/rfc5934>.

   [X.411]    ITU-T, "Information technology - Message Handling Systems
              (MHS): Message Transfer System: Abstract Service
              Definition and Procedures", ITU-T Recommendation X.411 |
              ISO/IEC 10021-4:1999, 1999.

Appendix A.  ASN.1 Module

   KMAttributes2012
     { joint-iso-itu-t(2) country(16) us(840) organization(1)
       gov(101) dod(2) infosec(1) modules(0) 39 }

   DEFINITIONS IMPLICIT TAGS ::=

   BEGIN

   -- EXPORT ALL

   IMPORTS

   -- From [RFC5911]

   aa-communityIdentifiers, CommunityIdentifier
     FROM CMSFirmwareWrapper-2009
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
         smime(16) modules(0) id-mod-cms-firmware-wrap-02(40) }

   -- From [RFC5911]

   aa-contentHint, ESSSecurityLabel, id-aa-securityLabel
     FROM ExtendedSecurityServices-2009
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
         smime(16) modules(0) id-mod-ess-2006-02(42) }

   -- From [RFC5911] [RFC5912]

   AlgorithmIdentifier{}, SMIME-CAPS, ParamOptions, KEY-WRAP
     FROM AlgorithmInformation-2009
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-algorithmInformation-02(58) }

   -- From [RFC5912]

   Name, Certificate
     FROM PKIX1Explicit-2009
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-pkix1-explicit-02(51) }

   -- From [RFC5912]

   GeneralNames, SubjectInfoAccessSyntax, id-pe-subjectInfoAccess
     FROM PKIX1Implicit-2009
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-pkix1-implicit-02(59) }

   -- FROM [RFC5912]

   ATTRIBUTE
     FROM PKIX-CommonTypes-2009
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-pkixCommon-02(57) }

   -- From [RFC6010]

   CMSContentConstraints
     FROM CMSContentConstraintsCertExtn
       { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          cmsContentConstr-93(42) }

   -- From [RFC6268]

   aa-binarySigningTime, BinaryTime
     FROM BinarySigningTimeModule-2010
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
         smime(16) modules(0) id-mod-binSigningTime-2009(55) }

   -- From [RFC6268]

   CertificateChoices, CertificateSet, Attribute {},
   aa-contentType, aa-messageDigest
     FROM CryptographicMessageSyntax-2010
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
         smime(16) modules(0) id-mod-cms-2009(58) }

   -- From [RFC7191]

   aa-keyPackageIdentifierAndReceiptRequest, SIREntityName
     FROM KeyPackageReceiptAndErrorModuleV2
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
         smime(16) modules(0) id-mod-keyPkgReceiptAndErrV2(63) }

   -- From [X.509]

   certificateExactMatch
     FROM CertificateExtensions
       { joint-iso-itu-t ds(5) module(1) certificateExtensions(26) 4 }

   ;

   -- ATTRIBUTES

   -- Replaces SignedAttributesSet information object set from
   -- [RFC6268].

   SignedAttributesSet ATTRIBUTE ::= {
     aa-contentType                           |
     aa-messageDigest                         |
     aa-contentHint                           |
     aa-communityIdentifiers                  |
     aa-binarySigningTime                     |
     aa-keyProvince-v2                        |
     aa-keyPackageIdentifierAndReceiptRequest |
     aa-manifest                              |
     aa-keyAlgorithm                          |
     aa-userCertificate                       |
     aa-keyPackageReceivers-v2                |
     aa-tsecNomenclature                      |
     aa-keyPurpose                            |
     aa-keyUse                                |
     aa-transportKey                          |
     aa-keyDistributionPeriod                 |
     aa-keyValidityPeriod                     |
     aa-keyDurationPeriod                     |
     aa-classificationAttribute               |
     aa-keyPackageType                        |
     aa-pkiPath                               |
     aa-usefulCertificates,
     ... }

   -- Replaces UnsignedAttributes from [RFC6268].

   UnsignedAttributes ATTRIBUTE ::= {
      ...
      }

   -- Replaces UnprotectedEnvAttributes from [RFC6268].

   UnprotectedEnvAttributes ATTRIBUTE ::= {
     aa-contentDecryptKeyIdentifier |
     aa-certificatePointers         |
     aa-cRLDistributionPoints,
     ...
     }

   -- Replaces UnprotectedEncAttributes from [RFC6268].

   UnprotectedEncAttributes ATTRIBUTE ::= {
     aa-certificatePointers |
     aa-cRLDistributionPoints,
     ...
     }

   -- Replaces AuthAttributeSet from [RFC6268]

   AuthAttributeSet ATTRIBUTE ::= {
     aa-contentType                           |
     aa-messageDigest                         |
     aa-contentHint                           |
     aa-communityIdentifiers                  |
     aa-keyProvince-v2                        |
     aa-binarySigningTime                     |
     aa-keyPackageIdentifierAndReceiptRequest |
     aa-manifest                              |
     aa-keyAlgorithm                          |
     aa-userCertificate                       |
     aa-keyPackageReceivers-v2                |
     aa-tsecNomenclature                      |
     aa-keyPurpose                            |
     aa-keyUse                                |
     aa-transportKey                          |
     aa-keyDistributionPeriod                 |
     aa-keyValidityPeriod                     |
     aa-keyDurationPeriod                     |
     aa-classificationAttribute               |
     aa-keyPackageType                        |
     aa-pkiPath                               |
     aa-usefulCertificates,
     ... }

   -- Replaces UnauthAttributeSet from [RFC6268]

   UnauthAttributeSet ATTRIBUTE ::= {
     ...
     }

   -- Replaces AuthEnvDataAttributeSet from [RFC6268]

   AuthEnvDataAttributeSet ATTRIBUTE ::= {
     aa-certificatePointers |
     aa-cRLDistributionPoints,
     ...
     }

    -- Replaces UnauthEnvDataAttributeSet from [RFC6268]

   UnauthEnvDataAttributeSet ATTRIBUTE ::= {
     ...
     }

   -- Replaces OneAsymmetricKeyAttributes from [RFC5958]

   OneAsymmetricKeyAttributes ATTRIBUTE ::= {
     aa-userCertificate            |
     aa-tsecNomenclature           |
     aa-keyPurpose                 |
     aa-keyUse                     |
     aa-transportKey               |
     aa-keyDistributionPeriod      |
     aa-keyValidityPeriod          |
     aa-keyDurationPeriod          |
     aa-classificationAttribute    |
     aa-splitIdentifier            |
     aa-signatureUsage-v3          |
     aa-otherCertificateFormats    |
     aa-pkiPath                    |
     aa-usefulCertificates,
     ... }

   -- Replaces SKeyPkgAttributes from [RFC6031]

   SKeyPkgAttributes ATTRIBUTE ::= {
     aa-keyAlgorithm                |
     aa-tsecNomenclature            |
     aa-keyPurpose                  |
     aa-keyUse                      |
     aa-keyDistributionPeriod       |
     aa-keyValidityPeriod           |
     aa-keyDurationPeriod           |
     aa-classificationAttribute     |
     aa-keyWrapAlgorithm            |
     aa-contentDecryptKeyIdentifier,
     ... }

   -- Replaces SKeyAttributes from [RFC6031]

   SKeyAttributes ATTRIBUTE ::= {
     aa-keyAlgorithm                |
     aa-tsecNomenclature            |
     aa-keyPurpose                  |
     aa-keyUse                      |
     aa-keyDistributionPeriod       |
     aa-keyValidityPeriod           |
     aa-keyDurationPeriod           |
     aa-classificationAttribute     |
     aa-splitIdentifier             |
     aa-keyWrapAlgorithm            |
     aa-contentDecryptKeyIdentifier,
     ... }

   -- Replaces ContentAttributeSet from [RFC6268]

   ContentAttributeSet ATTRIBUTE ::= {
     aa-communityIdentifiers                  |
     aa-keyPackageIdentifierAndReceiptRequest |
     aa-keyAlgorithm                          |
     aa-keyPackageReceivers-v2                |
     aa-tsecNomenclature                      |
     aa-keyPurpose                            |
     aa-keyUse                                |
     aa-transportKey                          |
     aa-keyDistributionPeriod                 |
     aa-transportKey                          |
     aa-keyDistributionPeriod                 |
     aa-keyValidityPeriod                     |
     aa-keyDurationPeriod                     |
     aa-classificationAttribute               |
     aa-keyPackageType                        |
     aa-pkiPath                               |
     aa-usefulCertificates,
     ... }

   -- Content Type, Message Digest, Content Hint, and Binary Signing
   -- Time are imported from [RFC6268].
   -- Community Identifiers is imported from [RFC5911].

   -- Key Province

   aa-keyProvince-v2 ATTRIBUTE ::= {
     TYPE KeyProvinceV2
     IDENTIFIED BY id-aa-KP-keyProvinceV2 }

   id-aa-KP-keyProvinceV2 OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes(5) 71 }

   KeyProvinceV2 ::= OBJECT IDENTIFIER

   -- Manifest Attribute

   aa-manifest ATTRIBUTE ::= {
     TYPE Manifest
     IDENTIFIED BY id-aa-KP-manifest }

   id-aa-KP-manifest OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes(5) 72 }

   Manifest ::= SEQUENCE SIZE (1..MAX) OF ShortTitle

   -- Key Algorithm Attribute

   aa-keyAlgorithm ATTRIBUTE ::= {
     TYPE KeyAlgorithm
     IDENTIFIED BY id-kma-keyAlgorithm }

   id-kma-keyAlgorithm  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 1 }

   KeyAlgorithm ::= SEQUENCE {
     keyAlg            OBJECT IDENTIFIER,
     checkWordAlg  [1] OBJECT IDENTIFIER OPTIONAL,
     crcAlg        [2] OBJECT IDENTIFIER OPTIONAL }

   -- User Certificate Attribute

   aa-userCertificate ATTRIBUTE ::= {
     TYPE Certificate
     EQUALITY MATCHING RULE certificateExactMatch
     IDENTIFIED BY id-at-userCertificate }

   id-at-userCertificate OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) ds(5) attributes(4) 36 }

   -- Key Package Receivers Attribute

   aa-keyPackageReceivers-v2 ATTRIBUTE ::= {
     TYPE KeyPkgReceiversV2
     IDENTIFIED BY id-kma-keyPkgReceiversV2 }

   id-kma-keyPkgReceiversV2  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 16 }

   KeyPkgReceiversV2 ::= SEQUENCE SIZE (1..MAX) OF KeyPkgReceiver

   KeyPkgReceiver ::= CHOICE {
     sirEntity  [0] SIREntityName,
     community  [1] CommunityIdentifier }

   -- TSEC Nomenclature Attribute

   aa-tsecNomenclature ATTRIBUTE ::= {
     TYPE TSECNomenclature
     IDENTIFIED BY id-kma-TSECNomenclature }

   id-kma-TSECNomenclature  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 3 }

   TSECNomenclature ::= SEQUENCE {
     shortTitle  ShortTitle,
     editionID   EditionID OPTIONAL,
     registerID  RegisterID OPTIONAL,
     segmentID   SegmentID OPTIONAL }

   ShortTitle ::= PrintableString

   EditionID ::= CHOICE {
     char CHOICE {
       charEdition      [1] CharEdition,
       charEditionRange [2] CharEditionRange },
     num CHOICE {
       numEdition       [3] NumEdition,
       numEditionRange  [4] NumEditionRange } }

   CharEdition ::= PrintableString

   CharEditionRange ::= SEQUENCE {
     firstCharEdition  CharEdition,
     lastCharEdition   CharEdition }

   NumEdition ::= INTEGER (0..308915776)

   NumEditionRange ::= SEQUENCE {
     firstNumEdition  NumEdition,
     lastNumEdition   NumEdition }

   RegisterID ::= CHOICE {
     register       [5] Register,
     registerRange  [6] RegisterRange }

   Register ::= INTEGER (0..2147483647)

   RegisterRange ::= SEQUENCE {
     firstRegister  Register,
     lastRegister   Register }

   SegmentID ::= CHOICE {
     segmentNumber  [7] SegmentNumber,
     segmentRange   [8] SegmentRange }

   SegmentNumber ::= INTEGER (1..127)

   SegmentRange ::= SEQUENCE {
     firstSegment  SegmentNumber,
     lastSegment   SegmentNumber }

   -- Key Purpose Attribute

   aa-keyPurpose ATTRIBUTE ::= {
     TYPE KeyPurpose
     IDENTIFIED BY id-kma-keyPurpose }

   id-kma-keyPurpose  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 13 }

   KeyPurpose ::= ENUMERATED {
     n-a    (0),   -- Not Applicable
     a     (65),   -- Operational
     b     (66),   -- Compatible Multiple Key
     l     (76),   -- Logistics Combinations
     m     (77),   -- Maintenance
     r     (82),   -- Reference
     s     (83),   -- Sample
     t     (84),   -- Training
     v     (86),   -- Developmental
     x     (88),   -- Exercise
     z     (90),   -- "On the Air" Testing
     ... -- Expect additional key purpose values -- }

   -- Key Use Attribute

   aa-keyUse ATTRIBUTE ::= {
     TYPE KeyUse
     IDENTIFIED BY id-kma-keyUse }

   id-kma-keyUse  OBJECT IDENTIFIER ::=
      { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
        dod(2) infosec(1) keying-material-attributes(13) 14 }

   KeyUse ::= ENUMERATED {
     n-a    (0),    -- Not Applicable
     ffk    (1),    -- FIREFLY/CROSSTALK Key (Basic Format)
     kek    (2),    -- Key Encryption Key
     kpk    (3),    -- Key Production Key
     msk    (4),    -- Message Signature Key
     qkek   (5),    -- QUADRANT Key Encryption Key
     tek    (6),    -- Traffic Encryption Key
     tsk    (7),    -- Transmission Security Key
     trkek  (8),    -- Transfer Key Encryption Key
     nfk    (9),    -- Netted FIREFLY Key
     effk  (10),    -- FIREFLY Key (Enhanced Format)
     ebfk  (11),    -- FIREFLY Key (Enhanceable Basic Format)
     aek   (12),    -- Algorithm Encryption Key
     wod   (13),    -- Word of Day
     kesk (246),    -- Key Establishment Key
     eik  (247),    -- Entity Identification Key
     ask  (248),    -- Authority Signature Key
     kmk  (249),    -- Key Modifier Key
     rsk  (250),    -- Revocation Signature Key
     csk  (251),    -- Certificate Signature Key
     sak  (252),    -- Symmetric Authentication Key
     rgk  (253),    -- Random Generation Key
     cek  (254),    -- Certificate Encryption Key
     exk  (255),    -- Exclusion Key
     ... -- Expect additional key use values -- }

   -- Transport Key Attribute

   aa-transportKey ATTRIBUTE ::= {
     TYPE TransOp
     IDENTIFIED BY id-kma-transportKey }

   id-kma-transportKey  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 15 }

   TransOp ::= ENUMERATED {
     transport    (1),
     operational  (2) }

   -- Key Distribution Period Attribute

   aa-keyDistributionPeriod ATTRIBUTE ::= {
     TYPE KeyDistPeriod
     IDENTIFIED BY id-kma-keyDistPeriod }

   id-kma-keyDistPeriod  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 5 }

   KeyDistPeriod ::= SEQUENCE {
     doNotDistBefore  [0] BinaryTime OPTIONAL,
     doNotDistAfter       BinaryTime }

   -- Key Validity Period Attribute

   aa-keyValidityPeriod ATTRIBUTE ::= {
     TYPE KeyValidityPeriod
     IDENTIFIED BY id-kma-keyValidityPeriod }

   id-kma-keyValidityPeriod  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 6 }

   KeyValidityPeriod ::= SEQUENCE {
     doNotUseBefore  BinaryTime,
     doNotUseAfter   BinaryTime OPTIONAL }

   -- Key Duration Attribute

   aa-keyDurationPeriod ATTRIBUTE ::= {
     TYPE KeyDuration
     IDENTIFIED BY id-kma-keyDuration }

   id-kma-keyDuration  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 7 }

   KeyDuration ::= CHOICE {
     hours   [0] INTEGER (1..ub-KeyDuration-hours),
     days        INTEGER (1..ub-KeyDuration-days),
     weeks   [1] INTEGER (1..ub-KeyDuration-weeks),
     months  [2] INTEGER (1..ub-KeyDuration-months),
     years   [3] INTEGER (1..ub-KeyDuration-years) }

   ub-KeyDuration-hours  INTEGER ::=  96
   ub-KeyDuration-days   INTEGER ::= 732
   ub-KeyDuration-weeks  INTEGER ::= 104
   ub-KeyDuration-months INTEGER ::=  72
   ub-KeyDuration-years  INTEGER ::= 100

   -- Classification Attribute

   -- The attribute syntax is imported from [RFC6268].  The term
   -- "classification" is used in this document, but the term "security
   -- label" is used in [RFC2634].  The terms have the same meaning.

   aa-classificationAttribute ATTRIBUTE ::= {
     TYPE Classification
     IDENTIFIED BY id-aa-KP-classification }

   id-aa-KP-classification OBJECT IDENTIFIER ::= id-aa-securityLabel

   Classification ::= ESSSecurityLabel

   id-enumeratedRestrictiveAttributes OBJECT IDENTIFIER ::=
     { 2 16 840 1 101 2 1 8 3 4 }

   id-enumeratedPermissiveAttributes OBJECT IDENTIFIER ::=
     { 2 16 840 1 101 2 1 8 3 1 }

   EnumeratedTag ::= SEQUENCE {
     tagName          OBJECT IDENTIFIER,
     attributeList    SET OF SecurityAttribute }

   SecurityAttribute ::= INTEGER (0..MAX)

   -- Split Identifier Attribute

   aa-splitIdentifier ATTRIBUTE ::= {
     TYPE SplitID
     IDENTIFIED BY id-kma-splitID }

   id-kma-splitID  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 11 }

   SplitID ::= SEQUENCE {
     half        ENUMERATED { a(0), b(1) },
     combineAlg  AlgorithmIdentifier
                   {COMBINE-ALGORITHM, {CombineAlgorithms}}  OPTIONAL }

   COMBINE-ALGORITHM ::= CLASS {
     &id                OBJECT IDENTIFIER UNIQUE,
     &Params            OPTIONAL,
     &paramPresence     ParamOptions DEFAULT absent,
     &smimeCaps         SMIME-CAPS OPTIONAL
   }
   WITH SYNTAX {
     IDENTIFIER &id
     [PARAMS [TYPE &Params] ARE &paramPresence]
     [SMIME-CAPS &smimeCaps]
   }

   CombineAlgorithms COMBINE-ALGORITHM ::= {
     ...
     }

   -- Key Package Type Attribute

   aa-keyPackageType ATTRIBUTE ::= {
     TYPE KeyPkgType
     IDENTIFIED BY id-kma-keyPkgType }

   id-kma-keyPkgType  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 12 }

   KeyPkgType ::= OBJECT IDENTIFIER

   -- Signature Usage Attribute

   aa-signatureUsage-v3 ATTRIBUTE ::= {
     TYPE SignatureUsage
     IDENTIFIED BY id-kma-sigUsageV3 }

   id-kma-sigUsageV3  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 22 }

   SignatureUsage ::= CMSContentConstraints

   -- Other Certificate Format Attribute

   aa-otherCertificateFormats ATTRIBUTE ::= {
     TYPE CertificateChoices
     IDENTIFIED BY id-kma-otherCertFormats }

   id-kma-otherCertFormats OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 19 }

   -- PKI Path Attribute

   aa-pkiPath ATTRIBUTE ::= {
     TYPE PkiPath
     IDENTIFIED BY id-at-pkiPath }

   id-at-pkiPath OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) ds(5) attributes(4) 70 }

   PkiPath ::= SEQUENCE SIZE (1..MAX) OF Certificate

   -- Useful Certificates Attribute

   aa-usefulCertificates ATTRIBUTE ::= {
     TYPE CertificateSet
     IDENTIFIED BY id-kma-usefulCerts }

   id-kma-usefulCerts OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 20 }

   -- Key Wrap Attribute

   aa-keyWrapAlgorithm ATTRIBUTE ::= {
     TYPE AlgorithmIdentifier{KEY-WRAP, {KeyEncryptionAlgorithmSet}}
     IDENTIFIED BY id-kma-keyWrapAlgorithm }

   id-kma-keyWrapAlgorithm OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) keying-material-attributes(13) 21 }

   KeyEncryptionAlgorithmSet KEY-WRAP ::= { ... }

   -- Content Decryption Key Identifier Attribute

   aa-contentDecryptKeyIdentifier ATTRIBUTE ::= {
     TYPE ContentDecryptKeyID
     IDENTIFIED BY id-aa-KP-contentDecryptKeyID }

   id-aa-KP-contentDecryptKeyID OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes(5) 66 }

   ContentDecryptKeyID::= OCTET STRING

   -- Certificate Pointers Attribute

   aa-certificatePointers ATTRIBUTE ::= {
     TYPE SubjectInfoAccessSyntax
     IDENTIFIED BY id-pe-subjectInfoAccess }

   -- CRL Pointers Attribute

   aa-cRLDistributionPoints ATTRIBUTE ::= {
     TYPE GeneralNames
     IDENTIFIED BY id-aa-KP-crlPointers }

   id-aa-KP-crlPointers  OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) attributes (5) 70 }

   -- ExtendedErrorCodes

   id-errorCodes OBJECT IDENTIFIER ::=
     { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
       dod(2) infosec(1) errorCodes(22) }

   id-missingKeyType OBJECT IDENTIFIER ::= {
     id-errorCodes 1 }

   id-privacyMarkTooLong OBJECT IDENTIFIER ::= {
     id-errorCodes 2 }

   id-unrecognizedSecurityPolicy OBJECT IDENTIFIER ::= {
     id-errorCodes 3 }

   END

Authors' Addresses

   Paul Timmel
   National Information Assurance Research Laboratory
   National Security Agency

   Email: pstimme@nsa.gov

   Russ Housley
   Vigil Security, LLC
   918 Spring Knoll Drive
   Herndon, VA 20170
   United States

   Email: housley@vigilsec.com

   Sean Turner
   IECA, Inc.
   3057 Nutley Street, Suite 106
   Fairfax, VA 22031
   United States

   Email: turners@ieca.com

 

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