Independent Submission V. Dolmatov, Ed.
Request for Comments: 7091 A. Degtyarev
Updates: 5832 Cryptocom, Ltd.
Category: Informational December 2013
ISSN: 20701721
GOST R 34.102012: Digital Signature Algorithm
Abstract
This document provides information about the Russian Federal standard
for digital signatures (GOST R 34.102012), which is one of the
Russian cryptographic standard algorithms (called GOST algorithms).
Recently, Russian cryptography is being used in Internet
applications, and this document provides information for developers
and users of GOST R 34.102012 regarding digital signature generation
and verification. This document updates RFC 5832.
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 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfceditor.org/info/rfc7091.
Copyright Notice
Copyright (c) 2013 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/licenseinfo) 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 ....................................................2
1.1. General Information ........................................2
1.2. The Purpose of GOST R 34.102012 ...........................3
1.3. Requirements Language ......................................3
2. Scope ...........................................................3
3. Definitions and Notations .......................................4
3.1. Definitions ................................................4
3.2. Notations ..................................................6
4. General Statements ..............................................7
5. Mathematical Conventions ........................................8
5.1. Mathematical Definitions ...................................9
5.2. Digital Signature Parameters ..............................10
5.3. Binary Vectors ............................................12
6. Main Processes .................................................12
6.1. Digital Signature Generation Process ......................13
6.2. Digital Signature Verification ............................13
7. Test Examples (Appendix to GOST R 34.102012) ..................14
7.1. The Digital Signature Scheme Parameters ...................15
7.2. Digital Signature Process (Algorithm I) ...................17
7.3. Verification Process of Digital Signature (Algorithm II) ..18
8. Security Considerations ........................................19
9. References .....................................................19
9.1. Normative References ......................................19
9.2. Informative References ....................................20
1. Introduction
1.1. General Information
1. GOST R 34.102012 [GOST34102012] was developed by the Center for
Information Protection and Special Communications of the Federal
Security Service of the Russian Federation with participation of
the open jointstock company "Information Technologies and
Communication Systems" (InfoTeCS JSC).
2. GOST R 34.102012 was approved and introduced by Decree #215 of
the Federal Agency on Technical Regulating and Metrology on
07.08.2012.
3. GOST R 34.102012 replaces GOST R 34.102001 [GOST34102001], a
national standard of the Russian Federation.
GOST R 34.102001 is superseded by GOST R 34.102012 from 1 January
2013. That means that all new systems that are presented for
certification MUST use GOST R 34.102012 and MAY use
GOST R 34.102001 also for maintaining compatibility with existing
systems. Usage of GOST R 34.102001 in current systems is allowed at
least for a 5year period.
This document updates RFC 5832 [RFC5832].
This document is an English translation of GOST R 34.102012;
[RFC6986] is an English translation of GOST R 34.112012; and
[RFC5832] is an English translation of GOST R 34.102001.
Terms and conceptions of this standard comply with the following
international standards:
o ISO 23822 [ISO23822],
o ISO/IEC 9796 [ISO97962][ISO97963],
o series of standards ISO/IEC 14888 [ISO148881] [ISO148882]
[ISO148883] [ISO148884], and
o series of standards ISO/IEC 10118 [ISO101181] [ISO101182]
[ISO101183] [ISO101184].
1.2. The Purpose of GOST R 34.102012
GOST R 34.102012 describes the generation and verification processes
for digital signatures, based on operations with an elliptic curve
points group, defined over a prime finite field.
The necessity for developing this standard is caused by the need to
implement digital signatures of varying resistance due to growth of
computer technology. Digital signature security is based on the
complexity of discrete logarithm calculation in an elliptic curve
points group and also on the security of the hash function used
(according to GOST R 34.112012 [GOST34112012]).
1.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Scope
GOST R 34.102012 defines an electronic digital signature (or simply
digital signature) scheme, digital signature generation and
verification processes for a given message (document), meant for
transmission via insecure public telecommunication channels in data
processing systems of different purposes.
Use of a digital signature based on GOST R 34.102012 makes
transmitted messages more resistant to forgery and loss of integrity,
in comparison with the digital signature scheme prescribed by the
previous standard.
GOST R 34.102012 is recommended for the creation, operation, and
modernization of data processing systems of various purposes.
3. Definitions and Notations
3.1. Definitions
The following terms are used in the standard:
appendix: bit string that is formed by a digital signature and by the
arbitrary text field [ISO148881].
signature key: element of secret data that is specific to the subject
and used only by this subject during the signature generation
process [ISO148881].
verification key: element of data mathematically linked to the
signature key data element that is used by the verifier during the
digital signature verification process [ISO148881].
domain parameter: element of data that is common for all the subjects
of the digital signature scheme, known or accessible to all the
subjects [ISO148881].
signed message: a set of data elements that consists of the message
and the appendix, which is a part of the message [ISO148881].
pseudorandom number sequence: a sequence of numbers that is obtained
during some arithmetic (calculation) process, used in a specific
case instead of a true random number sequence.
random number sequence: a sequence of numbers of which none can be
predicted (calculated) using only the preceding numbers of the
same sequence.
verification process: a process that uses the signed message, the
verification key, and the digital signature scheme parameters as
initial data and that gives the conclusion about digital signature
validity or invalidity as a result [ISO148881].
signature generation process: a process that uses the message, the
signature key, and the digital signature scheme parameters as
initial data and that generates the digital signature as the
result [ISO148881].
witness: element of data that states to the verifier whether the
digital signature is valid or invalid.
random number: a number chosen from the definite number set in such a
way that every number from the set can be chosen with equal
probability.
message: string of bits of a limited length [ISO148881].
hash code: string of bits that is a result of the hash function
[ISO148881].
hash function: the function that maps bit strings onto bit strings of
fixed length observing the following properties:
1. it is difficult to calculate the input data that is the pre
image of the given function value;
2. it is difficult to find another input data that is the pre
image of the same function value as is the given input data;
and
3. it is difficult to find a pair of different input data that
produces the same hash function value.
[ISO148881]
Notes:
1. Property 1 in the context of the digital signature area means
that it is impossible to recover the initial message using the
digital signature; property 2 means that it is difficult to
find another (falsified) message that produces the same
digital signature as a given message; property 3 means that it
is difficult to find a pair of different messages that both
produce the same signature.
2. In this standard, the terms "hash function", "cryptographic
hash function", "hashing function", and "cryptographic hashing
function" are synonymous to provide terminological succession
to native legal documents currently in force and scientific
publications.
(electronic) digital signature: string of bits that are obtained as a
result of the signature generation process [ISO148881].
Notes:
1. A string of bits that is a signature may have an internal
structure depending on the specific signature generation
mechanism.
2. In this standard, the terms "electronic signature", "digital
signature", and "electronic digital signature" are synonymous
to provide terminological succession to native legal documents
currently in force and scientific publications.
3.2. Notations
The following notations are used in this standard:
V_l set of all binary vectors of an lbit length
V_all set of all binary vectors of an arbitrary finite length
Z set of all integers
p prime number, p > 3
GF(p) finite prime field represented by a set of integers {0,
1, ..., p  1}
b (mod p) minimal nonnegative number, congruent to b modulo p
M user's message, M belongs to V_all
(H1  H2 ) concatenation of two binary vectors
a, b elliptic curve coefficients
m points of the elliptic curve group order
q subgroup order of group of points of the elliptic curve
O zero point of the elliptic curve
P elliptic curve point of order q
d integer  a signature key
Q elliptic curve point  a verification key
zeta digital signature for the message M
^ the power operator
/= nonequality
sqrt square root
4. General Statements
A commonly accepted digital signature scheme (model) consists of
three processes:
 generation of a pair of keys (for signature generation and for
signature verification),
 signature generation, and
 signature verification.
In GOST R 34.102012, a process for generating a pair of keys (for
signature and verification) is not defined. Characteristics and ways
to realize the process are defined by involved subjects, who
determine corresponding parameters by their agreement.
The digital signature mechanism is defined by the realization of two
main processes (Section 6):
 signature generation (Section 6.1), and
 signature verification (Section 6.2).
The digital signature is meant for the authentication of the
signatory of the electronic message. Besides, digital signature
usage gives an opportunity to provide the following properties during
signed message transmission:
 realization of control of the transmitted signed message
integrity,
 proof of the authorship of the signatory of the message, and
 protection of the message against possible forgery.
A schematic representation of the signed message is shown in
Figure 1.
appendix

++
 
++ ++   +
 message M  digital signature zeta  text 
++ ++   +
Figure 1: Signed Message Scheme
The field "digital signature" is supplemented by the field "text"
that can contain, for example, identifiers of the signatory of the
message and/or time label.
The digital signature scheme defined in GOST R 34.102012 must be
implemented using operations of the elliptic curve points group,
defined over a finite prime field, and also with the use of the hash
function.
The cryptographic security of the digital signature scheme is based
on the complexity of solving the problem of the calculation of the
discrete logarithm in the elliptic curve points group and also on the
security of the hash function used. The hash function calculation
algorithm is defined in GOST R 34.112012 [GOST34112012].
The digital signature scheme parameters needed for signature
generation and verification are defined in Section 5.2. This
standard provides the opportunity to select one of two options for
parameter requirements.
GOST R 34.102012 does not determine the process for generating the
parameters needed for the digital signature scheme. Possible sets of
these parameters are defined, for example, in [RFC4357].
The digital signature represented as a binary vector of a 512 or
1024bit length must be calculated using a definite set of rules, as
stated in Section 6.1.
The digital signature of the received message is accepted or denied
in accordance with the set of rules, as stated in Section 6.2.
5. Mathematical Conventions
To define a digital signature scheme, it is necessary to describe
basic mathematical objects used in the signature generation and
verification processes. This section lays out basic mathematical
definitions and requirements for the parameters of the digital
signature scheme.
5.1. Mathematical Definitions
Suppose a prime number p > 3 is given. Then, an elliptic curve E,
defined over a finite prime field GF(p), is the set of number pairs
(x,y), where x and y belong to Fp, satisfying the identity:
y^2 = x^3 + a * x + b (mod p), (1)
where a, b belong to GF(p) and 4 * a^3 + 27 * b^2 is not congruent to
zero modulo p.
An invariant of the elliptic curve is the value J(E), satisfying the
equality:
4 * a^3
J(E) = 1728 *  (mod p) (2)
4 * a^3 + 27 * b^2
Elliptic curve E coefficients a, b are defined in the following way
using the invariant J(E):
 a = 3 * k (mod p),
 (3)
 b = 2 * k (mod p),
J(E)
where k =  (mod p), J(E) /= 0 or 1728
1728  J(E)
The pairs (x, y) satisfying the identity (1) are called "the elliptic
curve E points"; x and y are called x and ycoordinates of the
point, correspondingly.
We will denote elliptic curve points as Q(x, y) or just Q. Two
elliptic curve points are equal if their x and ycoordinates are
equal.
On the set of all elliptic curve E points, we will define the
addition operation, denoted by "+". For two arbitrary elliptic curve
E points Q1 (x1, y1) and Q2 (x2, y2), we will consider several
variants.
Suppose coordinates of points Q1 and Q2 satisfy the condition x1 /=
x2. In this case, their sum is defined as a point Q3 (x3, y3), with
coordinates defined by congruencies:
 x3 = lambda^2  x1  x2 (mod p),
 (4)
 y3 = lambda * (x1  x3)  y1 (mod p),
y1  y2
where lambda =  (mod p).
x1  x2
If x1 = x2 and y1 = y2 /= 0, then we will define point Q3 coordinates
in the following way:
 x3 = lambda^2  x1 * 2 (mod p),
 (5)
 y3 = lambda * (x1  x3)  y1 (mod p),
3 * x1^2 + a
where lambda =  (mod p)
y1 * 2
If x1 = x2 and y1 = y2 (mod p), then the sum of points Q1 and Q2 is
called a zero point O, without determination of its x and y
coordinates. In this case, point Q2 is called a negative of point
Q1. For the zero point, the equalities hold:
O + Q = Q + O = Q, (6)
where Q is an arbitrary point of elliptic curve E.
A set of all points of elliptic curve E, including the zero point,
forms a finite abelian (commutative) group of order m regarding the
introduced addition operation. For m, the following inequalities
hold:
p + 1  2 * sqrt(p) =< m =< p + 1 + 2 * sqrt(p) (7)
The point Q is called "a point of multiplicity k", or just "a
multiple point of the elliptic curve E", if for some point P, the
following equality holds:
Q = P + ... + P = k * P (8)
+
k
5.2. Digital Signature Parameters
The digital signature parameters are:
 prime number p is an elliptic curve modulus.
 elliptic curve E, defined by its invariant J(E) or by coefficients
a, b belonging to GF(p).
 integer m is an elliptic curve E points group order.
 prime number q is an order of a cyclic subgroup of the elliptic
curve E points group, which satisfies the following conditions:
 m = nq, n belongs to Z, n >= 1
 (9)
 2^254 < q < 2^256 or 2^508 < q < 2^512
 point P /= O of an elliptic curve E, with coordinates (x_p, y_p),
satisfying the equality q * P = O.
 hash function h(.):V_all > V_l, which maps the messages
represented as binary vectors of arbitrary finite length onto
binary vectors of an lbit length. The hash function is defined
in GOST R 34.112012 [GOST34112012].
If 2^254 < q < 2^256, then l = 256.
If 2^508 < q < 2^512, then l = 512.
Every user of the digital signature scheme must have its personal
keys:
 signature key, which is an integer d, satisfying the inequality 0
< d < q;
 verification key, which is an elliptic curve point Q with
coordinates (x_q, y_q), satisfying the equality d * P = Q.
The previously introduced digital signature parameters must satisfy
the following requirements:
 it is necessary that the condition p^t /= 1 (mod q) holds for all
integers t = 1, 2, ..., B, where
B = 31 if 2^254 < q < 2^256, or
B = 131 if 2^508 < q < 2^512;
 it is necessary that the inequality m /= p holds;
 the curve invariant must satisfy the condition J(E) /= 0, 1728.
5.3. Binary Vectors
To determine the digital signature generation and verification
processes, it is necessary to map the set of integers onto the set of
binary vectors of an lbit length.
Consider the following binary vector of an lbit length where low
order bits are placed on the right, and highorder ones are placed on
the left:
H = (alpha[l1], ..., alpha[0]), H belongs to V_l (10)
where alpha[i], i = 0, ..., l1 are equal to 1 or to 0. The number
alpha belonging to Z is mapped onto the binary vector h, if the
equality holds:
alpha = alpha[0]*2^0 + alpha[1]*2^1 + ... + alpha[l1]*2^(l1) (11)
For two binary vectors H1 and H2:
H1 = (alpha[l1], ..., alpha[0]),
(12)
H2 = (beta[l1], ..., beta[0]),
which correspond to integers alpha and beta, we define a
concatenation (union) operation in the following way:
H1H2 = (alpha[l1], ..., alpha[0], beta[l1], ..., beta[0]) (13)
that is a binary vector of 2*lbit length, consisting of coefficients
of the vectors H1 and H2.
On the other hand, the introduced formulae define a way to divide a
binary vector H of 2*lbit length into two binary vectors of lbit
length, where H is the concatenation of the two.
6. Main Processes
In this section, the digital signature generation and verification
processes of a user's message are defined.
To realize the processes, it is necessary that all users know the
digital signature scheme parameters, which satisfy the requirements
of Section 5.2.
Besides, every user must have the signature key d and the
verification key Q(x_q, y_q), which also must satisfy the
requirements of Section 5.2.
6.1. Digital Signature Generation Process
It is necessary to perform the following actions (steps) to obtain
the digital signature for the message M belonging to V_all. This is
Algorithm I.
Step 1. Calculate the message hash code M:
H = h(M) (14)
Step 2. Calculate an integer alpha, the binary representation of
which is the vector H, and determine:
e = alpha (mod q) (15)
If e = 0, then assign e = 1.
Step 3. Generate a random (pseudorandom) integer k, satisfying the
inequality:
0 < k < q (16)
Step 4. Calculate the elliptic curve point C = k * P and determine:
r = x_C (mod q), (17)
where x_C is the xcoordinate of the point C. If r = 0,
return to step 3.
Step 5. Calculate the value:
s = (r * d + k * e) (mod q) (18)
If s = 0, return to Step 3.
Step 6. Calculate the binary vectors R and S, corresponding to r and
s, and determine the digital signature zeta = (R  S) as a
concatenation of these two binary vectors.
The initial data of this process are the signature key d and the
message M to be signed. The output result is the digital signature
zeta.
6.2. Digital Signature Verification
To verify the digital signature for the received message M, it is
necessary to perform the following actions (steps). This is
Algorithm II.
Step 1. Calculate the integers r and s using the received signature
zeta. If the inequalities 0 < r < q, 0 < s < q hold, go to
the next step. Otherwise, the signature is invalid.
Step 2. Calculate the hash code of the received message M:
H = h(M) (19)
Step 3. Calculate the integer alpha, the binary representation of
which is the vector H, and determine if:
e = alpha (mod q) (20)
If e = 0, then assign e = 1.
Step 4. Calculate the value:
v = e^(1) (mod q) (21)
Step 5. Calculate the values:
z1 = s * v (mod q), z2 = r * v (mod q) (22)
Step 6. Calculate the elliptic curve point C = z1 * P + z2 * Q and
determine:
R = x_C (mod q), (23)
where x_C is xcoordinate of the point.
Step 7. If the equality R = r holds, then the signature is accepted.
Otherwise, the signature is invalid.
The input data of the process are the signed message M, the digital
signature zeta, and the verification key Q. The output result is the
witness of the signature validity or invalidity.
7. Test Examples (Appendix to GOST R 34.102012)
This section is included in GOST R 34.102012 as a reference appendix
but is not officially mentioned as a part of the standard.
The values given here for the parameters p, a, b, m, q, P, the
signature key d, and the verification key Q are recommended only for
testing the correctness of actual realizations of the algorithms
described in GOST R 34.102012.
All numerical values are introduced in decimal and hexadecimal
notations. The numbers beginning with 0x are in hexadecimal
notation. The symbol "\\" denotes that the number continues on the
next line. For example, the notation:
12345\\
67890
0x499602D2
represents 1234567890 in decimal and hexadecimal number systems,
respectively.
7.1. The Digital Signature Scheme Parameters
The following parameters must be used for digital signature
generation and verification (see Section 5.2).
7.1.1. Elliptic Curve Modulus
The following value is assigned to parameter p in this example:
p = 57896044618658097711785492504343953926\\
634992332820282019728792003956564821041
p = 0x8000000000000000000000000000\\
000000000000000000000000000000000431
7.1.2. Elliptic Curve Coefficients
Parameters a and b take the following values in this example:
a = 7
a = 0x7
b = 43308876546767276905765904595650931995\\
942111794451039583252968842033849580414
b = 0x5FBFF498AA938CE739B8E022FBAFEF40563\\
F6E6A3472FC2A514C0CE9DAE23B7E
7.1.3. Elliptic Curve Points Group Order
Parameter m takes the following value in this example:
m = 5789604461865809771178549250434395392\\
7082934583725450622380973592137631069619
m = 0x80000000000000000000000000000\\
00150FE8A1892976154C59CFC193ACCF5B3
7.1.4. Order of Cyclic Subgroup of Elliptic Curve Points Group
Parameter q takes the following value in this example:
q = 5789604461865809771178549250434395392\\
7082934583725450622380973592137631069619
q = 0x80000000000000000000000000000001\\
50FE8A1892976154C59CFC193ACCF5B3
7.1.5. Elliptic Curve Point Coordinates
Point P coordinates take the following values in this example:
x_p = 2
x_p = 0x2
y_p = 40189740565390375033354494229370597\\
75635739389905545080690979365213431566280
y_p = 0x8E2A8A0E65147D4BD6316030E16D19\\
C85C97F0A9CA267122B96ABBCEA7E8FC8
7.1.6. Signature Key
It is supposed, in this example, that the user has the following
signature key d:
d = 554411960653632461263556241303241831\\
96576709222340016572108097750006097525544
d = 0x7A929ADE789BB9BE10ED359DD39A72C\\
11B60961F49397EEE1D19CE9891EC3B28
7.1.7. Verification Key
It is supposed, in this example, that the user has the verification
key Q with the following coordinate values:
x_q = 57520216126176808443631405023338071\\
176630104906313632182896741342206604859403
x_q = 0x7F2B49E270DB6D90D8595BEC458B5\\
0C58585BA1D4E9B788F6689DBD8E56FD80B
y_q = 17614944419213781543809391949654080\\
031942662045363639260709847859438286763994
y_q = 0x26F1B489D6701DD185C8413A977B3\\
CBBAF64D1C593D26627DFFB101A87FF77DA
7.2. Digital Signature Process (Algorithm I)
Suppose that after Steps 13 in Algorithm I (Section 6.1) are
performed, the following numerical values are obtained:
e = 2079889367447645201713406156150827013\\
0637142515379653289952617252661468872421
e = 0x2DFBC1B372D89A1188C09C52E0EE\\
C61FCE52032AB1022E8E67ECE6672B043EE5
k = 538541376773484637314038411479966192\\
41504003434302020712960838528893196233395
k = 0x77105C9B20BCD3122823C8CF6FCC\\
7B956DE33814E95B7FE64FED924594DCEAB3
And the multiple point C = k * P has the coordinates:
x_C = 297009809158179528743712049839382569\\
90422752107994319651632687982059210933395
x_C = 0x41AA28D2F1AB148280CD9ED56FED\\
A41974053554A42767B83AD043FD39DC0493
y[C] = 328425352786846634770946653225170845\\
06804721032454543268132854556539274060910
y[C] = 0x489C375A9941A3049E33B34361DD\\
204172AD98C3E5916DE27695D22A61FAE46E
Parameter r = x_C (mod q) takes the value:
r = 297009809158179528743712049839382569\\
90422752107994319651632687982059210933395
r = 0x41AA28D2F1AB148280CD9ED56FED\\
A41974053554A42767B83AD043FD39DC0493
Parameter s = (r * d + k * e)(mod q) takes the value:
s = 57497340027008465417892531001914703\\
8455227042649098563933718999175515839552
s = 0x1456C64BA4642A1653C235A98A602\\
49BCD6D3F746B631DF928014F6C5BF9C40
7.3. Verification Process of Digital Signature (Algorithm II)
Suppose that after Steps 13 in Algorithm II (Section 6.2) are
performed, the following numerical value is obtained:
e = 2079889367447645201713406156150827013\\
0637142515379653289952617252661468872421
e = 0x2DFBC1B372D89A1188C09C52E0EE\\
C61FCE52032AB1022E8E67ECE6672B043EE5
And the parameter v = e^(1) (mod q) takes the value:
v = 176866836059344686773017138249002685\\
62746883080675496715288036572431145718978
v = 0x271A4EE429F84EBC423E388964555BB\\
29D3BA53C7BF945E5FAC8F381706354C2
The parameters z1 = s * v (mod q) and z2 = r * v (mod q) take the
values:
z1 = 376991675009019385568410572935126561\\
08841345190491942619304532412743720999759
z1 = 0x5358F8FFB38F7C09ABC782A2DF2A\\
3927DA4077D07205F763682F3A76C9019B4F
z2 = 141719984273434721125159179695007657\\
6924665583897286211449993265333367109221
z2 = 0x3221B4FBBF6D101074EC14AFAC2D4F7\\
EFAC4CF9FEC1ED11BAE336D27D527665
The point C = z1 * P + z2 * Q has the coordinates:
x_C = 2970098091581795287437120498393825699\\
0422752107994319651632687982059210933395
x_C = 0x41AA28D2F1AB148280CD9ED56FED\\
A41974053554A42767B83AD043FD39DC0493
y[C] = 3284253527868466347709466532251708450\\
6804721032454543268132854556539274060910
y[C] = 0x489C375A9941A3049E33B34361DD\\
204172AD98C3E5916DE27695D22A61FAE46E
Then the parameter R = x_C (mod q) takes the value:
R = 2970098091581795287437120498393825699\\
0422752107994319651632687982059210933395
R = 0x41AA28D2F1AB148280CD9ED56FED\\
A41974053554A42767B83AD043FD39DC0493
Since the equality R = r holds, the digital signature is accepted.
8. Security Considerations
This entire document is about security considerations.
9. References
9.1. Normative References
[GOST34102001] "Information technology. Cryptographic data
security. Signature and verification processes of
[electronic] digital signature", GOST R 34.102001,
Gosudarstvennyi Standard of Russian Federation,
Government Committee of Russia for Standards, 2001.
(In Russian)
[GOST34102012] "Information technology. Cryptographic data
security. Signature and verification processes of
[electronic] digital signature", GOST R 34.102012,
Federal Agency on Technical Regulating and
Metrology, 2012.
[GOST34112012] "Information technology. Cryptographic Data
Security. Hashing function", GOST R 34.112012,
Federal Agency on Technical Regulating and
Metrology, 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4357] Popov, V., Kurepkin, I., and S. Leontiev,
"Additional Cryptographic Algorithms for Use with
GOST 2814789, GOST R 34.1094, GOST R 34.102001,
and GOST R 34.1194 Algorithms", RFC 4357, January
2006.
9.2. Informative References
[ISO23822] ISO, "Data processing  Vocabulary  Part 2:
Arithmetic and logic operations", ISO 23822, 1976.
[ISO97962] ISO/IEC, "Information technology  Security
techniques  Digital signatures giving message
recovery  Part 2: Integer factorization based
mechanisms", ISO/IEC 97962, 2010.
[ISO97963] ISO/IEC, "Information technology  Security
techniques  Digital signature schemes giving
message recovery  Part 3: Discrete logarithm based
mechanisms", ISO/IEC 97963, 2006.
[ISO148881] ISO/IEC, "Information technology  Security
techniques  Digital signatures with appendix  Part
1: General", ISO/IEC 148881, 2008.
[ISO148882] ISO/IEC, "Information technology  Security
techniques  Digital signatures with appendix  Part
2: Integer factorization based mechanisms", ISO/IEC
148882, 2008.
[ISO148883] ISO/IEC, "Information technology  Security
techniques  Digital signatures with appendix  Part
3: Discrete logarithm based mechanisms", ISO/IEC
148883,2006.
[ISO148884] ISO/IEC, "Information technology  Security
techniques  Digital signatures with appendix  Part
3: Discrete logarithm based mechanisms. Amendment
1. Elliptic Curve Russian Digital Signature
Algorithm, Schnorr Digital Signature Algorithm,
Elliptic Curve Schnorr Digital Signature Algorithm,
and Elliptic Curve Full Schnorr Digital Signature
Algorithm", ISO/IEC 148883:2006/Amd 1, 2010.
[ISO101181] ISO/IEC, "Information technology  Security
techniques  Hashfunctions  Part 1: General",
ISO/IEC 101181, 2000.
[ISO101182] ISO/IEC, "Information technology  Security
techniques  Hashfunctions  Part 2: Hash
functions using an nbit block cipher algorithm",
ISO/IEC 101182, 2010.
[ISO101183] ISO/IEC, "Information technology  Security
techniques  Hashfunctions  Part 3: Dedicated
hashfunctions", ISO/IEC 101183, 2004.
[ISO101184] ISO/IEC, "Information technology  Security
techniques  Hashfunctions  Part 4: Hash
functions using modular arithmetic", ISO/IEC
101184, 1998.
[RFC5832] Dolmatov, V., Ed., "GOST R 34.102001: Digital
Signature Algorithm", RFC 5832, March 2010.
[RFC6986] Dolmatov, V., Ed., and A. Degtyarev, "GOST R
34.112012: Hash Function", RFC 6986, August 2013.
Authors' Addresses
Vasily Dolmatov (editor)
Cryptocom, Ltd.
14 Kedrova St., Bldg. 2
Moscow, 117218
Russian Federation
EMail: dol@cryptocom.ru
Alexey Degtyarev
Cryptocom, Ltd.
14 Kedrova St., Bldg. 2
Moscow, 117218
Russian Federation
EMail: alexey@renatasystems.org

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