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RFC 2057 - Source Directed Access Control on the Internet

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Network Working Group                                         S. Bradner
Request for Comments: 2057                            Harvard University
Category: Informational                                    November 1996

             Source Directed Access Control on the Internet

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

1.  Abstract

   This memo was developed from a deposition that I submitted as part of
   a challenge to the Communications Decency Act of 1996, part of the
   Telecommunications Reform Act of 1996.  The Telecommunications Reform
   Act is a U.S. federal law substantially changing the regulatory
   structure in the United States in the telecommunications arena.  The
   Communications Decency Act (CDA) part of this law has as its aim the
   desire to protect minors from some of the material carried over
   telecommunications networks.  In particular the law requires that the
   sender of potentially offensive material take "effective action" to
   ensure that it is not presented to minors.  A number of people have
   requested that I publish the deposition as an informational RFC since
   some of the information in it may be useful where descriptions of the
   way the Internet and its applications work could help clear up
   confusion in the technical feasibility of proposed content control

2.  Control and oversight over the Internet

   No organization or entity operates or controls the Internet.  The
   Internet consists of tens of thousands of local networks linking
   millions of computers, owned by governments, public institutions,
   non-profit organizations, and private companies around the world.
   These local networks are linked together by thousands of Internet
   service providers which interconnect at dozens of points throughout
   the world.  None of these entities, however, controls the Internet;
   each entity only controls its own computers and computer networks,
   and the links allowed into those computers and computer networks.

   Although no organizations control the Internet, a limited number of
   organizations are responsible for the development of communications
   and operational standards and protocols used on the Internet.  These
   standards and protocols are what allow the millions of different (and
   sometimes incompatible) computers worldwide to communicate with each

   other.  These standards and protocols are not imposed on any computer
   or computer network, but any computer or computer network must follow
   at least some of the standards and protocols to be able to
   communicate with other computers over the Internet.

   The most significant of the organizations involved in defining these
   standards include the Internet Society (ISOC), the Internet
   Architecture Board (IAB), Internet Engineering Steering Group (IESG),
   and the Internet Engineering Task Force (IETF).   The following
   summary outlines the relationship of these four organizations:

   The Internet Society (ISOC) is a professional society that is
   concerned with the growth and evolution of the worldwide Internet,
   with the way in which the Internet is and can be used, and with the
   social, political, and technical issues which arise as a result.  The
   ISOC Trustees are responsible for approving appointments to the IAB
   from among the nominees submitted by the IETF nominating committee
   and ratifying the IETF Standards Process.

   The Internet Architecture Board (IAB) is a technical advisory group
   of the ISOC.  It is chartered to provide oversight of the
   architecture of the Internet and its protocols, and to serve, in the
   context of the Internet standards process, as a body to which the
   decisions of the IESG may be appealed.  The IAB is responsible for
   approving appointments to the IESG from among the nominees submitted
   by the IETF nominations committee and advising the IESG on the
   approval of Working Group charters.

   The Internet Engineering Steering Group (IESG) is responsible for
   technical management of IETF activities and the Internet standards
   process.  As a part of the ISOC, it administers the process according
   to the rules and procedures which have been ratified by the ISOC
   Trustees.  The IESG is directly responsible for the actions
   associated with entry into and movement along the Internet "standards
   track," including final approval of specifications as Internet

   The Internet Engineering Task Force (IETF) is a self-organized group
   of people who make technical and other contributions to the
   engineering and evolution of the Internet and its technologies.  It
   is the principal body engaged in the development of new Internet
   standard specifications.  The IETF is divided into eight functional
   areas.  They are: Applications, Internet, IP: Next Generation,
   Network Management, Operational Requirements, Routing, Security,
   Transport and User Services.  Each area has one or two area
   directors.  These area directors, along with the IETF/IESG Chair,
   form the IESG.

   In addition to these organizations, there are a variety of other
   formal and informal groups that develop standards and agreements
   about specialized or emerging areas of the Internet.   For example,
   the World Wide Web Consortium has developed agreements and standards
   for the Web.

   None of these organizations controls, governs, runs, or pays for the
   Internet.  None of these organizations controls the substantive
   content available on the Internet.  None of these organizations has
   the power or authority to require content providers to alter, screen,
   or restrict access to content on the Internet other than content that
   they themselves create.

   Beyond the standards setting process, the only Internet functions
   that are centralized are the allocation of numeric addresses to
   networks and the registration of "domain names."  Three entities
   around the world share responsibility for ensuring that each network
   and computer on the Internet has a unique 32-bit numeric "IP" address
   (such as, and for ensuring that all "domain names"
   (such as "harvard.edu") are unique.  InterNIC allocates IP addresses
   for the Americas, and has counterparts in Europe and Asia.  InterNIC
   allocates large blocks of IP addresses to major Internet providers,
   who in turn allocate smaller blocks to smaller Internet providers
   (who in turn allocate even smaller blocks to other providers or end
   users).  InterNIC does not, however, reliably receive information on
   who receives each numeric IP address, and thus cannot provide any
   central database of computer addresses.  In addition, a growing
   number of computers access the Internet indirectly through address
   translating devices such as application "firewalls".  With these
   devices the IP address used by a computer on the "inside" of the
   firewall is translated to another IP address for transmission over
   the Internet.  The IP address used over the Internet can be
   dynamically assigned from a pool of available IP addresses at the
   time that a communication is initiated.  In this case the IP
   addresses used inside the firewall is not required to be globally
   unique and the IP addresses used over the Internet do not uniquely
   identify a specific computer.  Neither the InterNIC nor its
   counterparts in Europe and Asia control the substantive content
   available on the Internet, nor do they have the power or authority to
   require content providers to alter, screen, or restrict access to
   content on the Internet.

3.  Characteristics of Internet communications

   There are a wide variety of methods of communications over the
   Internet, including electronic mail, mail exploders such as listserv,
   USENET newsgroups, Internet Relay Chat, gopher, FTP, and the World
   Wide Web.  With each of these forms of communication, the speaker has
   little or no way to control or verify who receives the communication.

   As detailed below, for each of these methods of communications, it is
   either impossible or very difficult for the speaker to restrict
   access to his or her communications "by requiring use of a verified
   credit card, debit account, adult access code, or adult personal
   identification number." Similarly, for each of these methods of
   communication, there are no feasible actions that I know of that the
   speaker can take that would be reasonably effective to "restrict or
   prevent access by minors" to the speaker's communications.

   With each of these methods of communications, it is either
   technologically impossible or practically infeasible for the speaker
   to ensure that the speech is not "available" to a minor.  For most of
   these methods--mail exploders such as listserv, USENET newsgroups,
   Internet Relay Chat, gopher, FTP, and the World Wide Web--there are
   technological obstacles to a speaker knowing about or preventing
   access by minors to a communication.  Yet even for the basic point-
   to-point communication of electronic mail, there are practical and
   informational obstacles to a speaker ensuring that minors do not have
   access to a communication that might be considered "indecent" or
   "patently offensive" in some communities.

3.1 Point-to-Point Communications

3.1.1  Electronic Mail.

   Of all of the primary methods of communication on the Internet, there
   is the highest likelihood that the sender of electronic mail will
   personally know the intended recipient (and know the intended
   recipient's true e-mail address), and thus the sender (i.e., the
   speaker or content provider) may be able to transmit potentially
   "indecent" or "patently offensive" content with relatively little
   concern that the speech might be "available" to minors.

   There is significantly greater risk for the e-mail speaker who does
   not know the intended recipient.  As a hypothetical example, if an
   AIDS information organization receives from an unknown individual a
   request for information via electronic mail, the organization has no
   practical or effective way to verify the identity or age of the e-
   mail requester.

   An electronic mail address provides no authoritative information
   about the addressee.  Addresses are often chosen by the addressees
   themselves, and may or may not be based on the addressees' real
   names.  For millions of people with e-mail addresses, no additional
   information is available over the Internet.  Where information is
   available (via, for example, inquiry tools such as "finger"), it is
   usually provided by the addressee, and thus may not be accurate
   (especially in a case of a minor seeking to obtain information the
   government has restricted to adults).

   There exists no universal or even extensive "white pages" listing of
   e-mail addresses and corresponding names or telephone numbers.  Given
   the rapidly expanding and global nature of the Internet, any attempt
   as such a listing likely will be incomplete (and likely will not
   contain information about the age of the e-mail addressee).  Nor is
   there any systematic, practical, and efficient method to obtain the
   identity of an e-mail address holder from the organization or
   institution operating the addressee's computer system.

   Moreover, it is relatively simple for someone to create an e-mail
   "alias" to send and receive mail under a different name.  Thus, a
   given e-mail address may not even be the true e-mail address of the
   recipient.  On some systems, for example, an individual seeking to
   protect his or her anonymity could easily create a temporary e-mail
   address for the sole purpose of requesting information from an AIDS
   information resource.  In addition, there exist "anonymous remailers"
   which replace the original e-mail address on messages with a randomly
   chosen new one.  The remailer keeps a record of the relationship
   between the original and the replacement name so that return mail
   will get forwarded to the right person.  These remailers are used
   frequently for discussion or support groups on sensitive or
   controversial topics such as AIDS.

   Thus, there is no reasonably effective method by which one can obtain
   information from existing online information sources about an e-mail
   address sufficient to ensure that a given address is used by an adult
   and not a minor.

   Absent the ability to comply with the Communications Decency Act
   based on information from existing online information sources, an e-
   mail speaker's only recourse is to interrogate the intended e-mail
   recipient in an attempt to verify that the intended recipient is an
   adult.  Such verification inherently and unavoidably imposes the
   burden of an entirely separate exchange of communications prior to
   sending the e-mail itself, and is likely to be unreliable if the
   recipient intends to deceive the speaker.

   This separate preliminary communication is required because with
   electronic mail, there is a complete electronic and temporal
   "disconnect" between the sender and recipient.  Electronic mail can
   be routed through numerous computers between the sender and the
   recipient, and the recipient may not "log in" to retrieve mail until
   days or even weeks after the sender sent the mail.  Thus, at no point
   in time is there any direct or even indirect electronic linkage
   between sender and recipient that would allow the sender to
   interrogate the recipient prior to sending an e-mail.  Thus,
   unavoidably, the Communications Decency Act requires that the sender
   incur the administrative (and in some cases financial) cost of an
   entirely separate exchange of communications between sender and
   recipient prior to the sender having sufficient information to ensure
   that the recipient is an adult.   Even if the sender were to
   establish that an e-mail addressee is not a minor, the sender could
   not be sure that the addressee was not sharing their computer account
   with someone else, as is frequently done, who is a minor.

   If an e-mail is part of a commercial transaction of sufficient value
   to justify the time and expense of obtaining payment via credit card
   from the e-mail addressee, an e-mail sender may be able to utilize
   the credit card or debit account options set out in the
   Communications Decency Act.  At this time, however, one cannot verify
   a credit or debit transaction over the Internet, and thus an e-mail
   speaker would have to incur the expense of verifying the transaction
   via telephone or separate computer connection to the correct banking
   entity.  Because of current concerns about data security on the
   Internet, such an e-mail credit card transaction would likely also
   require that the intended e-mail recipient transmit the credit card
   information to the e-mail sender via telephone or the postal service.

   Similarly, utilizing the "adult access code" or "adult personal
   identification number" options set out in the statute would at this
   time require the creation and maintenance of a database of adult
   codes.  While such a database would not be an insurmountable
   technological problem, it would require a significant amount of human
   clerical time to create and maintain the information.  As with the
   credit or debit transactions, an adult code database would also
   likely require that information be transmitted by telephone or postal

   Moreover, such an adult access code would likely be very ineffective
   at screening access by minors.  For the adult access code concept to
   work at all, any such code would have to be transmitted over the
   Internet, and thus would be vulnerable to interception and
   disclosure.  Any sort of "information based" code--that is, a code
   that consists of letters and numbers transmitted in a message--could
   be duplicated and circulated to other users on the Internet.  It is

   highly likely that valid adult access codes would themselves become
   widely distributed on the Internet, allowing industrious minors to
   obtain a valid code and thus obtain access the material sought to be

   A somewhat more effective alternative to this type of "information
   based" access code would be to link such a code to the unique 32-bit
   numeric "IP" addresses of networks and computers on the Internet.
   Under this approach, "adult" information would only be transmitted to
   the particular computer with the "approved" IP address.  For tens of
   millions of Internet users, however, IP addresses for a given access
   session are dynamically assigned at the time of the access, and those
   users will almost certainly utilize different IP addresses in
   succeeding sessions.  For example, users of the major online services
   such as America Online (AOL) are only allocated a temporary IP
   address at the time they link to the service, and the AOL user will
   not retain that IP address in later sessions.  Also, as discussed
   above, the use of "firewalls" can dynamically alter the apparent IP
   address of computers accessing the Internet.  Thus, any sort of IP
   address-based screening system would exclude tens of millions of
   potential recipients, and thus would not be a viable screening

   At bottom, short of incurring the time and expense of obtaining and
   charging the e-mail recipient's credit card, there are no reasonably
   effective methods by which an e-mail sender can verify the identity
   or age of an intended e-mail recipient even in a one-to-one
   communication to a degree of confidence sufficient to ensure
   compliance with the Communications Decency Act (and avoid the Act's
   criminal sanction).

3.2 Point-to-Multipoint Communications

   The difficulties described above for point-to-point communications
   are magnified many times over for point-to-multipoint communications.
   In addition, for almost all major types of point-to-multipoint
   communications on the Internet, there is a technological obstacle
   that makes it impossible or virtually impossible for the speaker to
   control who receives his or her speech.  For these types of
   communications over the Internet, reasonably effective compliance
   with the Communications Decency Act is impossible.

3.2.1 Mail Exploders

   Essentially an extension of electronic mail allowing someone to
   communicate with many people by sending a single e-mail, "mail
   exploders" are an important means by which the Internet user can
   exchange ideas and information on particular topics with others

   interested in the topic.  "Mail exploders" is a generic term covering
   programs such as "listserv" and "Majordomo." These programs typically
   receive electronic mail messages from individual users, and
   automatically retransmit the message to all other users who have
   asked to receive postings on the particular list.  In addition to
   listserv and Majordomo, many e-mail retrieval programs contain the
   option to receive messages and automatically forward the messages to
   other recipients on a local mailing list.

   Mail exploder programs are relatively simple to establish.  The
   leading programs such as listserv and Majordomo are available for
   free, and once set up can generally run unattended.  There is no
   practical way to measure how many mailing lists have been established
   worldwide, but there are certainly tens of thousands of such mailing
   lists on a wide range of topics.

   With the leading mail exploder programs, users typically can add or
   remove their names from the mailing list automatically, with no
   direct human involvement.  To subscribe to a mailing list, a user
   transmits an e-mail to the automated list program.  For example, to
   subscribe to the "Cyber-Rights" mailing list (relating to censorship
   and other legal issues on the Internet) one sends e-mail addressed to
   "listserv@cpsr.org" and includes as the first line of the body of the
   message the words "subscribe cyber-rights name" (inserting a person's
   name in the appropriate place).  In this example, the listserv
   program operated on the cpsr.org computer would automatically add the
   new subscriber's e-mail address to the mailing list.  The name
   inserted is under the control of the person subscribing, and thus may
   not be the actual name of the subscriber.

   A speaker can post to a mailing list by transmitting an e-mail
   message to a particular address for the mailing list.  For example,
   to post a message to the "Cyber-Rights" mailing list, one sends the
   message in an e-mail addressed to "cyber-rights@cpsr.org".  Some
   mailing lists are "moderated," and messages are forwarded to a human
   moderator who, in turn, forwards messages that moderator approves of
   to the whole list.   Many mailing lists, however, are unmoderated and
   postings directed to the appropriate mail exploder programs are
   automatically distributed to all users on the mailing list.  Because
   of the time required to review proposed postings and the large number
   of people posting messages, most mailing lists are not moderated.

   An individual speaker posting to a mail exploder mailing list cannot
   control who has subscribed to the particular list.  In many cases,
   the poster cannot even find out the e-mail address of who has
   subscribed to the list.  A speaker posting a message to a list thus
   has no way to screen or control who receives the message.  Even if
   the mailing list is "moderated," an individual posting to the list
   still cannot control who receives the posting.

   Moreover, the difficulty in knowing (and the impossibility of
   controlling) who will receive a posting to a mailing list is
   compounded by the fact that it is possible that mail exploder lists
   can themselves be entered as a subscriber to a mailing list.  Thus,
   one of the "subscribers" to a mailing list may in fact be another
   mail exploder program that re-explodes any messages transmitted using
   the first mailing list.  Thus, a message sent to the first mailing
   list may end up being distributed to many entirely separate mailing
   lists as well.

   Based on the current operations and standards of the Internet, it
   would be impossible for someone posting to a listserv to screen
   recipients to ensure the recipients were over 17 years of age.  Short
   of not speaking at all, I know of no actions available to a speaker
   today that would be reasonably effective at preventing minors from
   having access to messages posted to mail exploder programs.
   Requiring such screening for any messages that might be "indecent" or
   "patently offensive" to a minor would have the effect of banning such
   messages from this type of mailing list program.

   Even if one could obtain a listing of the e-mail addresses that have
   subscribed to a mailing list, one would then be faced with the same
   obstacles described above that face a point-to-point e-mail sender.
   Instead of obtaining a credit card or adult access code from a single
   intended recipient, however, a posted to a mailing list may have to
   obtain such codes from a thousand potential recipients, including new
   mailing list subscribers who may have only subscribed moments before
   the poster wants to post a message.  As noted above, complying with
   the Communications Decency Act for a single e-mail would be very
   difficult.  Complying with the Act for a single mailing list posting
   with any reasonable level of effectiveness is impossible.

3.2.2  USENET Newsgroups.

   One of the most popular forms of communication on the Internet is the
   USENET newsgroup.  USENET newsgroups are similar in objective to mail
   exploder mailing lists--to be able to communicate easily with others
   who share an interest in a particular topic--but messages are
   conveyed across the Internet in a very different manner.

   USENET newsgroups are distributed message databases that allow
   discussions and exchanges on particular topics.   USENET newsgroups
   are disseminated using ad hoc, peer-to-peer connections between
   200,000 or more computers (called USENET "servers") around the world.
   There are newsgroups on more than twenty thousand different subjects.
   Collectively, almost 100,000 new messages (or "articles") are posted
   to newsgroups each day.   Some newsgroups are "moderated" but most
   are open access.

   For unmoderated newsgroups, when an individual user with access to a
   USENET server posts a message to a newsgroup, the message is
   automatically forwarded to adjacent USENET servers that furnish
   access to the newsgroup, and it is then propagated to the servers
   adjacent to those servers, etc.  The messages are temporarily stored
   on each receiving server, where they are available for review and
   response by individual users.  The messages are automatically and
   periodically purged from each system after a configurable amount of
   time to make room for new messages.  Responses to messages--like the
   original messages--are automatically distributed to all other
   computers receiving the newsgroup.  The dissemination of messages to
   USENET servers around the world is an automated process that does not
   require direct human intervention or review.

   An individual who posts a message to a newsgroup has no ability to
   monitor or control who reads the posted message.  When an individual
   posts a message, she transmits it to a particular newsgroup located
   on her local USENET server.  The local service then automatically
   routes the message to other servers (or in some cases to a
   moderator), which in turn allow the users of those servers to read
   the message.  The poster has no control over the handling of her
   message by the USENET servers worldwide that receive newsgroups.
   Each individual server is configured by its local manager to
   determine which newsgroups it will accept.   There is no mechanism to
   permit distribution based on characteristics of the individual
   messages within a newsgroup.

   The impossibility of the speaker controlling the message distribution
   is made even more clear by the fact that new computers and computer
   networks can join the USENET news distribution system at any time.
   To obtain newsgroups, the operator of a new computer or computer
   network need only reach agreement with a neighboring computer that
   already receives the newsgroups.  Speakers around the world do not
   learn that the new computer had joined the distribution system.
   Thus, just as a speaker cannot know or control who receives a
   message, the speaker does not even know how many or which computers
   might receive a given newsgroup.

   For moderated newsgroups, all messages to the newsgroup are forwarded
   to an individual who can screen them for relevance to the topics
   under discussion.  The screening process, however, does not increase
   the ability of the original speaker to control who receives a given
   message.  A newsgroup moderator has as little control as the original
   speaker over who receives a message posted to the newsgroup.

   Based on the current operations and standards of the Internet, it
   would be impossible for someone posting to a USENET newsgroup to
   screen recipients to ensure that the recipients were over 17 years of
   age.  Short of not speaking at all, I know of no actions available to
   a speaker today that would be reasonably effective at preventing
   minors from having access to USENET newsgroup messages.  Requiring
   such screening for any messages that might be "indecent" or "patently
   offensive" to a minor would have the effect of banning such messages
   from USENET newsgroups.

   A speaker also has no means by which he or she could require
   listeners to provide a credit card, debit account, adult access code,
   or adult personal identification number.  Each individual USENET
   server controls access to the newsgroups on that server, and a
   speaker has no ability to force a server operator to take any
   particular action.  The message is out of the speaker's hands from
   the moment the message is posted.

   Moreover, even if one hypothesized a system under which a newsgroup
   server would withhold access to a message until the speaker received
   a credit card, debit account, adult access code, or adult personal
   identification number from the listener, there would be no feasible
   way for the speaker to receive such a number.  Because a listener may
   retrieve a message from a newsgroup days after the speaker posted the
   message, such a hypothetical system would require the speaker either
   to remain at his or her computer 24 hours a day for as many as ten
   days after posting the message, or to finance, develop, and maintain
   an automated system to receive and validate access numbers.  All of
   this effort would be required for the speaker to post even a single
   potentially "patently offensive" message to a single newsgroup.

   Moreover, even if such a hypothetical system did exist and a speaker
   were willing to remain available 24 hours a day (or operate a costly
   automated system) in order to receive access numbers, not all
   computers that receive USENET newsgroups could reasonably transmit
   such access numbers.  Some computers that receive newsgroups do so
   only by a once-a-day telephone connection to another newsgroup
   server.  Some of these computers do not have any other type of
   Internet connection, and indeed some computers that receive USENET
   newsgroups do not even utilize the TCP/IP communications protocol
   that is required for direct or real time communications on the

   Internet.  These computers would have no means by which a prospective
   listener's access code could be communicated back to a speaker.

   It is my opinion that if this hypothetical access system ever were
   created, it would be so burdensome as to effectively ban from USENET
   newsgroups messages that might be "indecent" or "patently offensive."
   Moreover, the communications standards and protocols that would allow
   such a hypothetical access system have not as of today been
   developed, and no Internet standards setting body of which I am aware
   is currently developing such standards and protocols.  Specifically,
   such a hypothetical access system is not part of the "next
   generation" Internet Protocol that I helped to develop.

3.2.3  Internet Relay Chat.

   Another method of communication on the Internet is called "Internet
   Relay Chat" (or IRC).  IRC allows for real time communication between
   two or more Internet users.  IRC is analogous to a telephone party
   line, using a computer and keyboard rather than a telephone.  With
   IRC, however, at anyone time there are thousands of different party
   lines available, in which collectively tens of thousands of users are
   engaging in discussions, debates, and conversations on a huge range
   of subjects.  Moreover, an individual can create a new party line to
   discuss a different topic at any time.  While many discussions on IRC
   are little more than social conversations between the participants,
   there are often conversations on important issues and topics.
   Although I have not personally operated an IRC server in my career, I
   am familiar enough with the operations of IRC servers to be able to
   identify the obstacles that a speaker would encounter attempting to
   identify other participants and to verify that those participants
   were not minors.

   There exists a network of dozens of IRC servers across the world.  To
   speak through IRC, a speaker connects to one of these servers and
   selects the topic the speaker wishes to "join."  Within a particular
   topic (once a speaker joins a topic), all speakers on that topic can
   see and read everything that everyone else transmits.  As a practical
   matter, there is no way for each person who joins a discussion to
   interrogate all other participants (sometimes dozens of participants)
   as to their identity and age.  Because people join or drop out of
   discussions on a rolling basis, the discussion line would be
   overwhelmed with messages attempting to verify the identity of the

   Also as a practical matter, there is no way that an individual
   speaker or an individual IRC server operator could enforce an "adults
   only" rule for a selection of the discussion topics.  Dozens of IRC
   servers are interconnected globally so that people across the world

   can talk to each other.  Thus, a speaker connected to an IRC server
   in the United States can speak directly to a listener in Asia or
   Europe.  There is no practical way that a speaker in the United
   States can be reasonably certain that a given IRC discussion is in
   fact "adults only."

   Nor can a speaker, prior to or at the time of joining an IRC
   discussion, ascertain with any confidence the identity of the other
   participants in the discussion.  Individual participants in an IRC
   conversation are able to participate anonymously by using a
   pseudonym.  A new speaking joining the conversation can see a list of
   pseudonyms of other participants, but has no possibly way of
   determining the real identify (or even the real e-mail address) of
   the individuals behind each pseudonym.

   Based on the current operations and standards of the Internet, it
   would be impossible for someone participating in a IRC discussion to
   screen recipients with a level of certainty needed to ensure the
   recipients were over 17 years of age.  Short of not speaking at all,
   I know of no actions available to a speaker today that would be
   reasonably effective at preventing minors from having access to
   speech in an IRC discussion.  Requiring such screening of recipients
   by the speakers for any IRC discussions that might be "indecent" or
   "patently offensive" to a minor would have the effect of banning such

4.0  Information Retrival Systems

   With FTP (or File Transfer Protocol), gopher, and the World Wide Web,
   the Internet is a vast resource for information made available to
   users around the world.  All three methods (FTP, gopher, and the Web)
   are specifically geared toward allowing thousands or millions of
   users worldwide to access content on the Internet, and none are
   specifically designed to limit access based on criteria such as the
   age of the Internet user.  Currently much of this information is
   offered for free access.

4.1 Anonymous FTP

   "Anonymous FTP" is a basic method by which a content provider can
   make content available to users on the Internet.   FTP is a protocol
   that allows the efficient and error free transfer of files from one
   computer to another.  To make content available via FTP, a content
   provider establishes an "Anonymous FTP server" capable of receiving
   FTP requests from remote users.   This approach is called "anonymous"
   because when a remote user connects to an FTP server, the remote user
   enters the word "anonymous" in response to the server's request for a
   user name.   By convention, the remote user is requested to enter his

   or her e-mail address when prompted for a "password."  The user is
   then given access to a restricted portion of the server disk and to
   the files in that area.  Even though the user may have entered their
   e-mail address in response to the password prompt, there is no
   effective validation or screening is possible using the FTP server
   software that is currently available.  Using currently available FTP
   software, a content provider has no way to screen access by
   "anonymous" users that may be minors.  Even if a content provider
   could determine the age of a particular remote user, the currently
   available FTP software cannot be set to limit the user's access to
   non-"adult" file areas.

   FTP server software can allow non-"anonymous" users to access the FTP
   server, and in that mode can require the users to have individual
   passwords that are verified against a pre-existing list of passwords.
   There are two major problems, however, that prevent this type of
   non-"anonymous" FTP access from being used to allow broad access to
   information over the Internet (as anonymous FTP can allow).  First,
   with current server software each non-"anonymous" FTP user must be
   given an account on the server computer, creating a significant
   administrative burden and resource drain.  If more than a limited
   number of users want access to the FTP system, the requirement of
   separate accounts would quickly overwhelm the capacity of the server
   to manage the accounts--the FTP server software was not designed to
   manage thousands or millions of different user/password combinations.
   Second, under existing FTP server software, each of these named users
   would have complete access to the server file system, not a
   restricted area like the anonymous FTP function supports.  This would
   create a significant security problem.  For these two reasons, as a
   practical matter FTP cannot be used to give broad access to content
   except via the anonymous FTP option (which, as noted above, does not
   allow for screening or blocking of minors).

   As discussed below with regard to the World Wide Web, even if someone
   re-designed the currently available FTP server software to allow the
   screening of minors, the administrative burden of such screening
   would in many cases overwhelm the resources of the content provider.

   Based on the current operations and standards of the Internet, it is
   not possible or practically feasible for someone operating an
   anonymous FTP file server to screen recipients with a level of
   certainty needed to ensure the recipients were over 17 years of age.
   Short of not operating an anonymous FTP server at all, I know of no
   actions available to a content provider today that would be
   reasonably effective at preventing minors from having access to
   "adult" files on the FTP server.  Requiring such screening by
   anonymous FTP server operators to prevent minors from accessing FTP
   files that might be "indecent" or "patently offensive" to a minor
   would have the effect of banning such anonymous FTP access.

4.2  Gopher.

   The gopher program is similar to FTP in that it allows for basic
   transfer of files from one computer to another, but it is also a
   precursor to the World Wide Web in that it allows a user to
   seamlessly jump from one gopher file server to another in order to
   locate the desired information.  The development of gopher and the
   linking of gopher servers around the worlds dramatically improved the
   ability of Internet users to locate information across the Internet.

   Although in many ways an improvement over FTP, gopher is simpler than
   FTP in that users need not enter any username or password to gain
   access to files stored on the gopher server.   Under currently
   available gopher server software, a content provider has no built-in
   ability to screen users.  Thus a content provider could not prevent
   minors from retrieving "adult" files.

   As discussed below with regard to the World Wide Web, even if the
   gopher server software allowed the screening of minors, the
   administrative burden of such screening would in many cases overwhelm
   the resources of the content provider.

   Based on the current operations and standards of the Internet, it is
   not possible for someone operating a gopher file server to screen
   recipients with a level of certainty needed to ensure the recipients
   were over 17 years of age.  Short of not operating a gopher server at
   all, I know of no actions available to a content provider today that
   would be reasonably effective at preventing minors from having access
   to "adult" files on a gopher server.  Requiring such screening of
   users by gopher server operators to prevent minors from accessing
   files that might be "indecent" or "patently offensive" to a minor
   would have the effect of banning gopher servers wherever there is any
   such material.

4.3  World Wide Web (WWW).

   Fast becoming the most well known method of communicating on the
   Internet, the "World Wide Web" offers users the easy ability to
   locate and view a vast array of content on the Internet.  The Web
   uses a "hypertext" formatting language called hypertext markup
   language (HTML), and Web "browsers" can display HTML documents
   containing text, images, and sound.  Any HTML document can include
   links to other types of information or resources anywhere in the
   world, so that while viewing an HTML document that, for example,
   describes resources available on the Internet, an individual can
   "click" using a computer mouse on the description of the resource and
   be immediately connected to the resource itself.  Such "hyperlinks"
   allow information to be accessed and organized in very flexible ways,
   and allow individuals to locate and efficiently view related
   information even if the information is stored on numerous computers
   all around the world.

   Unlike with USENET newsgroups, mail exploders, FTP, and gopher, an
   operator of a World Wide Web server does have some ability to
   interrogate a user of a Web site on the server, and thus has some
   ability to screen out users.  An HTML document can include a fill-in-
   the-blank "form" to request information from a visitor to a Web site,
   and this information can be transmitted back to the Web server.  The
   information received can then be processed by a computer program
   (usually a "Common Gateway Interface," or "CGI," script), and based
   on the results of that computer program the Web server could grant or
   deny access to a particular Web page.  Thus, it is possible for some
   (but not all, as discussed below) World Wide Web sites to be designed
   to "screen" visitors to ensure that they are adults.

   The primary barrier to such screening is the administrative burden of
   creating and maintaining the screening system.  For an individual Web
   site to create a software system capable of screening thousands of
   visitors a day, determining (to the extent possible) whether a
   visitor is an adult or a minor, and maintaining a database to allow
   subsequent access to the Web site would require a significant on-
   going effort.  Moreover, as discussed above with regard to electronic
   mail, the task of actually establishing a Web visitor's identity or
   "verifying" a credit card would require a significant investment of
   administrative and clerical time.  As there is no effective method to
   establish identity over the Internet, nor is there currently a method
   to verify credit card numbers over the Internet (and given the
   current cost of credit card verifications done by other means), this
   type of identification process is only practical for a commercial
   entity that is charging for access to the Web information.

   Beyond the major administrative burden that would be required for a
   Web site host to comply with the Communications Decency Act, there
   are two additional problems presented by the Act.  First, many Web
   publishers cannot utilize computer programs such as CGI scripts to
   process input from a Web visitor.  For example, I have been informed
   that the major online services such as America Online and Compuserve
   do not allow their customers to run CGI scripts or other processes
   that could be a significant drain on the online services' computers
   as well as a potential security risk.  Thus, for this category of Web
   publisher, the Communications Decency Act works as a ban on any
   arguably "indecent" or "patently offensive" speech.  It is impossible
   for this category of Web publisher to control access to their Web

   Moreover, even for Web publishers who can use CGI scripts to screen
   access, the existence of Web page caching on the Internet can make
   such screening ineffective.  "Caching" refers to a method to speed up
   access to Internet resources.  Caching is often used at one or both
   ends of, for example, a transatlantic or transpacific cable that
   carries Internet communications.  An example of caching might occur
   when a Internet user in Europe requests access to a World Wide Web
   page located in the United States.  The request travels by
   transatlantic cable to the United States, and the Web page is
   transmitted back across the ocean to Europe (and ultimately to the
   user who requested access).  But, the operator of the transatlantic
   cable will place the Web page in a storage "cache" located on the
   European side of the cable.  Then, if a second Internet user in
   Europe requests the same Web page, the operator of the transatlantic
   cable will intercept the request and provide the page from its
   "cache" (thereby reducing traffic on the transatlantic cable).  This
   type of caching typically occurs without the awareness of the
   requesting user.  Moreover, in this scenario, the original content
   provider is not even aware that the second user requested the Web
   page--and the original content provider has no opportunity to screen
   the access by the second user.  Nevertheless, the original content
   provider risks prosecution if the content is "adult" content and the
   second requester is a minor.  The use of caching web servers is
   rapidly increasing within the United States (mostly to help moderate
   the all too rapid growth in Internet traffic), and thus can affect
   entirely domestic communications.  For example, a growing number of
   universities use caching web servers to reduce the usage of the link
   to their Internet service provider.  In light of this type of
   caching, efforts to screen access to Web pages can only at best be
   partially effective.

   In light of the existence of Web page caching on the Internet, it
   would be extremely difficult if not impossible to for someone
   operating a World Wide Web server to ensure that no minors received
   "adult" content.

   Moreover, for those Web page publishers who lack access to CGI
   scripts, there is no possible way for them to screen recipients to
   ensure that all recipients are over 17 years of age.  For these
   content providers, short of not supporting World Wide Web access to
   their materials, I know of no actions available to them that would be
   reasonably effective at preventing minors from having access to
   "adult" files on a World Wide Web server.  Requiring such screening
   by these Web publishers to prevent minors from accessing files that
   might be "indecent" or "patently offensive" to a minor would have the
   effect of banning their speech on the World Wide Web.

   The Web page caching described above contributes to the difficulty of
   determining with specificity the number of visitors to a particular
   Web site.  Some Web servers can count how many different Web clients,
   some of which could be caching Web servers, requested access to a Web
   site.  Some Web servers can also count how many "hits"--or separate
   file accesses--were made on a particular Web site (a single access to
   a Web page that contains a images or graphic icons would likely be
   registered as more than one "hit").  With caching, the actual number
   of users that retrieved information that originated on a particular
   Web server is likely to be greater than the number of "hits" recorded
   for the server.

5.0  Client-end Blocking

   As detailed above, for many important methods of communication on the
   Internet, the senders--the content providers--have no ability to
   ensure that their messages are only available to adults.  It is also
   not possible for a Internet service provider or large institutional
   provider of access to the Internet (such as a university) to screen
   out all or even most content that could be deemed "indecent" or
   "patently offensive" (to the extent those terms can be understood at
   all).  A large institution could at least theoretically screen a
   portion of the communications over the Internet, scanning for example
   for "indecent" words, but not pictures.  Such a screening program
   capable of screening a high volume of Internet traffic at the point
   of its entry into the institution would require an investment of
   computing resources of as much as one million dollars per major
   Internet information conduit.  In addition it would be quit difficult
   to configure such a system to only control the content for those
   users that are under-age recipients, since in many cases the
   information would be going to a server within the university where
   many users, under-age and not, would have access to it.

   Based on my experience and knowledge of the Internet, I believe that
   the most effective way to monitor, screen, or control the full range
   of information transmitted over the Internet to block undesired
   content is at the client end--that is, by using software installed in
   the individual user's computer.  Such software could block certain
   forms of incoming transmissions by using content descriptive tags in
   the messages, or could use content ratings developed by third parties
   to select what can and cannot be retrieved for display on a user's

6.0  Tagging Material

   I am informed that the government in this action may advocate the use
   of special tags or flags in electronic mail messages, USENET
   newsgroup postings, and World Wide Web HTML documents to indicate
   "adult" material.  To my knowledge, no Internet access software or
   World Wide Web browsers are currently configurable to block material
   with such tags.  Thus, the headers and flags the government may
   advocate is currently an ineffective means to ensure the blocking of
   access by minors to "adult" material.  Even in a predictable future
   where there are defined standards for such tags and there are
   readably available browsers that are configurable to make use of
   those tags, a content provider--e.g., a listserv or Newsgroup poster
   or a Web page author--will have little power to ensure that the
   client software used to receive the postings was in all cases
   properly configured to recognize these tags and to block access to
   the posting when required.  Thus I feel that the tagging that may be
   proposed by the government would in fact not be "effective" in
   ensuring that the poster's speech would not be "available to a person
   under 18 years of age," as the Communications Decency Act requires.
   Although I strongly support both voluntary self-rating and third-
   party rating (as described in the preceding paragraph), I do not feel
   that the use of tags of this type would satisfy the speaker's
   obligation to take effective actions to ensure that "patently
   offensive" material would not be "available" to minors.  Furthermore,
   since it is impossible to embed such flags or headers in many of the
   documents currently made available by anonymous FTP, gopher and the
   World Wide Web without rendering the files useless (executable
   programs for example), any government proposal to require the use of
   tags to indicate "adult" material would not allow the continued use
   of those methods of communication for speech that might be deemed
   "indecent" or "patently offensive."

   With the exception of electronic mail and e-mail exploders all of the
   methods of Internet communications discussed above require an
   affirmative action by the listener before the communication takes
   place.  A listener must take specific action to receive
   communications from USENET newsgroups, Internet Relay Chat, gopher,

   FTP, and the World Wide Web.  In general this is also true for e-mail
   exploders except in the case where a third party subscribes the user
   to the exploder list.  These communications over the Internet do not
   "invade" a person's home or appear on a person's computer screen
   unbidden.  Instead, a person must almost always take specific
   affirmative steps to receive information over the Internet.

7.0  Acknowledgment

   I owe a great deal of thanks to John Morris of Jenner and Block, one
   of the law firms involved in the CDA challenge.  Without his
   extensive help this document would not exist, or if it did, it would
   be even more scattered.

8.0 Security Considerations

   To be actually able to do the type of content access control that the
   CDA envisions would require a secure Internet infrastructure along
   with secure ways to determine the minor status of potential
   reciepiants around the world.  Developing such a system is outside of
   the scope of this document.

9.0 Author's Address

   Scott Bradner
   Harvard University
   1350 Mass Ave.
   Cambridge MA 02138 USA

   Phone: +1 617 495 3864
   EMail: sob@harvard.edu


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