Skip to main content

GOST R 34.12-2015: Block Cipher "Kuznyechik"
draft-dolmatov-kuznyechik-00

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7801.
Author Vasily Dolmatov
Last updated 2015-10-08
RFC stream (None)
Formats
IETF conflict review conflict-review-dolmatov-kuznyechik, conflict-review-dolmatov-kuznyechik, conflict-review-dolmatov-kuznyechik, conflict-review-dolmatov-kuznyechik, conflict-review-dolmatov-kuznyechik, conflict-review-dolmatov-kuznyechik
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Became RFC 7801 (Informational)
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-dolmatov-kuznyechik-00
Internet Engineering Task Force                         V. Dolmatov, Ed.
Internet-DraftResearch Computer Center M.V. Lomonosov Moscow State Unive
Intended status: Informational                           October 8, 2015
Expires: April 10, 2016

              GOST R 34.12-2015: Block Cipher "Kuznyechik"
                      draft-dolmatov-kuznyechik-00

Abstract

   This document is intended to be a source of information about the
   Russian Federal standard block cipher with block length of n=128
   bits, which is also referred as "Kuznyechik" [GOST3412-2015].This
   algorithm is one of the Russian cryptographic standard algorithms
   (called GOST algorithms).

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 10, 2016.

Copyright Notice

   Copyright (c) 2015 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.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Dolmatov                 Expires April 10, 2016                 [Page 1]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

Table of Contents

   1.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  General Information . . . . . . . . . . . . . . . . . . . . .   3
   3.  Definitions and Notations . . . . . . . . . . . . . . . . . .   3
     3.1.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Notations . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Parameter Values  . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Nonlinear Bijection . . . . . . . . . . . . . . . . . . .   5
     4.2.  Linear Transformation . . . . . . . . . . . . . . . . . .   6
     4.3.  Transformations . . . . . . . . . . . . . . . . . . . . .   6
     4.4.  Key schedule  . . . . . . . . . . . . . . . . . . . . . .   7
     4.5.  Basic encryption algorithm  . . . . . . . . . . . . . . .   7
       4.5.1.  Encryption  . . . . . . . . . . . . . . . . . . . . .   8
       4.5.2.  Decryption  . . . . . . . . . . . . . . . . . . . . .   8
   5.  Examples (Informative)  . . . . . . . . . . . . . . . . . . .   8
     5.1.  Transformation S  . . . . . . . . . . . . . . . . . . . .   8
     5.2.  Transformation R  . . . . . . . . . . . . . . . . . . . .   8
     5.3.  Transformation L  . . . . . . . . . . . . . . . . . . . .   8
     5.4.  Key schedule  . . . . . . . . . . . . . . . . . . . . . .   9
     5.5.  Test encryption . . . . . . . . . . . . . . . . . . . . .  10
     5.6.  Test decryption . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Scope

   The Russian Federal standard [GOST3412-2015] specifies basic block
   ciphers used as cryptographic techniques for information processing
   and information protection including the provision of
   confidentiality, authenticity, and integrity of information during
   information transmission, processing and storage in computer-aided
   systems.

   The cryptographic algorithms specified in this Standard are designed
   both for hardware and software implementation.  They comply with
   modern cryptographic requirements, and put no restrictions on the
   confidentiality level of the protected information.

   The Standard applies to developing, operation, and modernization of
   the information systems of various purposes.

   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 [RFC2119].

Dolmatov                 Expires April 10, 2016                 [Page 2]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

2.  General Information

   The block cipher "Kuznyechik" [GOST3412-2015] 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 Joint-Stock company "Information Technologies and
   Communication Systems" (InfoTeCS JSC).  GOST R 34.12-2015 was
   approved and introduced by Decree #749 of the Federal Agency on
   Technical Regulating and Metrology on 19.06.2015.

   Terms and concepts in the standard comply with the following
   international standards:

   o  ISO/IEC 10116 [ISO-IEC10116],

   o  series of standards ISO/IEC 18033 [ISO-IEC18033-1],
      [ISO-IEC18033-3].

3.  Definitions and Notations

   The following terms and their corresponding definitions are used in
   the standard.

3.1.  Definitions

   Definitions

      encryption algorithm: process which transforms plaintext into
      ciphertext (Clause 2.19 of [ISO-IEC18033-1]),

      decryption algorithm: process which transforms ciphertext into
      plaintext (Clause 2.14 of [ISO-IEC18033-1]),

      basic block cipher: block cipher which for a given key provides a
      single invertible mapping of the set of fixed-length plaintext
      blocks into ciphertext blocks of the same length,

      block: string of bits of a defined length (Clause 2.6 of
      [ISO-IEC18033-1]),

      block cipher: symmetric encipherment system with the property that
      the encryption algorithm operates on a block of plaintext, i.e. a
      string of bits of a defined length, to yield a block of ciphertext
      (Clause 2.7 of [ISO-IEC18033-1]),

         Note: In GOST R 34.12-2015, it is established that the terms
         "block cipher" and "block encryption algorithm" are synonyms.

Dolmatov                 Expires April 10, 2016                 [Page 3]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

      encryption: reversible transformation of data by a cryptographic
      algorithm to produce ciphertext, i.e., to hide the information
      content of the data (Clause 2.18 of [ISO-IEC18033-1]),

      round key: sequence of symbols which is calculated from the key
      and controls a transformation for one round of a block cipher,

      key: sequence of symbols that controls the operation of a
      cryptographic transformation (e.g., encipherment, decipherment)
      (Clause 2.21 of [ISO-IEC18033-1]),

         Note: In GOST R 34.12-2015, the key must be a binary sequence.

      plaintext: unencrypted information (Clause 3.11 of
      [ISO-IEC10116]),

      key schedule: calculation of round keys from the key,

      decryption: reversal of a corresponding encipherment (Clause 2.13
      of [ISO-IEC18033-1]),

      symmetric cryptographic technique: cryptographic technique that
      uses the same secret key for both the originator`s and the
      recipient`s transformation (Clause 2.32 of [ISO-IEC18033-1]),

      cipher: alternative term for encipherment system (Clause 2.20 of
      [ISO-IEC18033-1]),

      ciphertext: data which has been transformed to hide its
      information content (Clause 3.3 of [ISO-IEC10116]).

3.2.  Notations

   The following notations are used in the standard:

         V*  the set of all binary vector-strings of a finite length
      (hereinafter referred to as the strings) including empty string,

        V_s  the set of all binary strings of length s, where s is a
      non-negative integer; substrings and string components are
      enumerated from right to left starting from zero,

      U[*]W  direct (Cartesian) product of two set Us and W,

        |A|  the number of components (the length) of a string A
      belonging to V* (if A is an empty string, then |A| = 0),

Dolmatov                 Expires April 10, 2016                 [Page 4]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

       A||B  concatenation of strings A, B both belonging to V*, i.e., a
      string from V_(|A|+|B|), where the left substring from V_|A| is
      equal to A and the right subdtring from V_|B| is equal to B,

    Z_(2^n)  ring of residues modulo 2^n,

          Q  finite field GF(2)[x]/p(x), where p(x)=x^8+x^7+x^6+x+1
      belongs to GF(2)[x]; elements of field Q are represented by
      integers in such way that element z_0+z_1*theta+...+z_7*theta^7
      belonging to Q corresponds to integer z_0+2*z_1+...+2^7*z_7, where
      z_i=0 or z_i=1, i=0,1,...,7 and theta denotes a residue class
      modulo p(x) containing x,

      (xor)  exclusive-or of the two binary strings of the same length,

   Vec_s: Z_(2^s) -> V_s  bijective mapping which maps an element from
      ring Z_(2^s) into its binary representation, i.e., for an element
      z of the ring Z_(2^s), represented by the residue z_0 + (2*z_1) +
      ... + (2^(s-1)*z_(s-1)), where z_i in {0, 1}, i = 0, ..., n-1, the
      equality Vec_s(z) = z_(s-1)||...||z_1||z_0 holds,

   Int_s: V_s -> Z_(2^s)  the mapping inverse to the mapping Vec_s,
      i.e., Int_s = Vec_s^(-1),

   nabla: V_8 -> F  bijective mapping which maps a binary string from
      V_8 into an element from field Q as follows: string
      z_7||...||z_1||z_0, where z_i in {0, 1}, i = 0, ..., 7,
      corresponds to the element z_0+(z_1*theta)+...+(z_7*theta^7)
      belonging to Z,

   delta: F -> V8  the mapping inverse to the mapping nabla, i.e., delta
      = nabla^(-1),

         PS  composition of mappings, where the mapping S applies first,

        P^s  composition of mappings P^(s-1) and P, where P^1=P,

4.  Parameter Values

4.1.  Nonlinear Bijection

   The bijective nonlinear mapping is a substitution: Pi =
   (Vec_8)Pi'(Int_8): V_8 -> V_8, where Pi': Z_(2^8) -> Z_(2^8).  The
   values of the substitution Pi' are specified below as an array Pi' =
   (Pi'(0), Pi'(1), ... , Pi'(255)):

Dolmatov                 Expires April 10, 2016                 [Page 5]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

    Pi' =
   (       252, 238, 221,  17, 207, 110,  49,  22, 251, 196, 250,
           218,  35, 197,   4,  77, 233, 119, 240, 219, 147,  46,
           153, 186,  23,  54, 241, 187,  20, 205,  95, 193, 249,
            24, 101,  90, 226,  92, 239,  33, 129,  28,  60,  66,
           139,   1, 142,  79,   5, 132,   2, 174, 227, 106, 143,
           160,   6,  11, 237, 152, 127, 212, 211,  31, 235,  52,
            44,  81, 234, 200,  72, 171, 242,  42, 104, 162, 253,
            58, 206, 204, 181, 112,  14,  86,   8,  12, 118,  18,
           191, 114,  19,  71, 156, 183,  93, 135,  21, 161, 150,
            41,  16, 123, 154, 199, 243, 145, 120, 111, 157, 158,
           178, 177,  50, 117,  25,  61, 255,  53, 138, 126, 109,
            84, 198, 128, 195, 189,  13,  87, 223, 245,  36, 169,
            62, 168,  67, 201, 215, 121, 214, 246, 124,  34, 185,
             3, 224,  15, 236, 222, 122, 148, 176, 188, 220, 232,
            40,  80,  78,  51,  10,  74, 167, 151,  96, 115,  30,
             0,  98,  68,  26, 184,  56, 130, 100, 159,  38,  65,
           173,  69,  70, 146,  39,  94,  85,  47, 140, 163, 165,
           125, 105, 213, 149,  59,   7,  88, 179,  64, 134, 172,
            29, 247,  48,  55, 107, 228, 136, 217, 231, 137, 225,
            27, 131,  73,  76,  63, 248, 254, 141,  83, 170, 144,
           202, 216, 133,  97,  32, 113, 103, 164,  45,  43,   9,
            91, 203, 155,  37, 208, 190, 229, 108,  82,  89, 166,
           116, 210, 230, 244, 180, 192, 209, 102, 175, 194,  57,
            75,  99, 182).

4.2.  Linear Transformation

   The linear transformation is denoted by l: (V_8)^16 -> V_8, and
   defined as:

                l(a_15,...,a_0) = nabla(148*delta(a_15) + 32*delta(a_15) + 133*delta(a_13) +
                16*delta(a_12) + 194*delta(a_11) + 192*delta(a_10) + 1*delta(a_9) + 251*delta(a_8) +
                1*delta(a_7) + 192*delta(a_6) + 194*delta(a_5) + 16*delta(a_4) +
                133*delta(a_3) + 32*delta(a_2) + 148*delta(a_1) +1*delta(a_0)),

   for all a_i belonging to V_8, i = 0, 1, ..., 15, where the addition
   and multiplication operations are in the field Q, and constants are
   elements of the field as defined above.

4.3.  Transformations

   The following transformations are applicable for encryption and
   decryption algorithms:

   X[x]:V_128->V_128  X[k](a)=x(xor)a, where k, a belong to V_128,

Dolmatov                 Expires April 10, 2016                 [Page 6]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

   S:V_128-> V_128  S(a)=(a_15||...||a_0)=pi(a_15)||...||pi(a_0), where
      a_15||...||a_0 belongs to V_128, a_i belongs to V_8, i=0,1,...,15,

   S^(-1):V_128-> V_128  the inverse transformation of S, which may be
      calculated, for example, as follows:
      S^(-1)(a_15||...||a_0)=pi^(-1) (a_15)||...||pi^(-1)(a_0), where
      a_15||...||a_0 belongs to V_128, a_i belongs to V_8, i=0,1,...,15,
      pi^(-1) is the inverse of pi.,

   R:V_128-> V_128  R(a_15||...||a_0)=l(a_15,...,a_0)||a_15||...||a_1,
      where a_15||...||a_0 belongs to V_128, a_i belongs to V_8,
      i=0,1,...,15,

   L:V_128-> V_128  L(a)=R^(16)(a), where a belongs to V_128,

   R^(-1):V_128-> V_128  the inverse transformation of R, which may be
      calculated, for example, as follows: R^(-1)(a_15||...||a_0)=a_14||
      a_13||...||a_0||l(a_14,a_13,...,a_0,a_15), where a_15||...||a_0
      belongs to V_128, a_i belongs to V_8, i=0,1,...,15, pi^(-1) is the
      inverse of pi,

   L^(-1):V_128-> V_128  L^(-1)(a)=(R^(-1))(16)(a), where a belongs to
      V_128,

   F[k]:V_128[*]V_128 -> V_128[*]V_128
      F[k](a_1,a_0)=(LSX[k](a_1)(xor)a_0,a_1), where k, a_0, a_1 belong
      to V_128.

4.4.  Key schedule

   Key schedule uses round constants C_i belonging to V_128, i=1, 2,
   ..., 32, defined as

                   C_i=L(Vec_128(i)), i=1,2,...,32.

   Round keys K_i, i=1, 2, ..., 10 are derived from key
   K=k_255||...||k_0 belonging to V_256, k_i belongs to V_1, i=0, 1,
   ..., 255, as follows:

                K_1=k_255||...||k_128;
                K_2=k_127||...||k_0;
                (K_(2i+1),K_(2i+2))=F[C_(8(i-1)+8)]... F[C_(8(i-1)+1)](K_(2i-1),K_(2i)), i=1,2,3,4.

4.5.  Basic encryption algorithm

Dolmatov                 Expires April 10, 2016                 [Page 7]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

4.5.1.  Encryption

   Depending on the values of round keys K_1,...,K_10, the encryption
   algorithm is a substitution E_(K_1,...,K_10) defined as follows:

                E_(K_1,...,K_10)(a)=X[K_10]LSX[K_9]...LSX[K_2]LSX[K_1](a),

   where a belongs to V_128.

4.5.2.  Decryption

   Depending on the values of round keys K_1,...,K_10, the decryption
   algorithm is a substitution D_(K_1,...,K_10) defined as follows:

                D_(K_1,...,K_10)(a)=X[K_1]L^(-1)S^(-1)X[K_2]...L^(-1)S^(-1)X[K_9] L^(-1)S^(-1)X[K_10](a),

   where a belongs to V_128.

5.  Examples (Informative)

   This section is for information only and is not a normative part of
   the standard.

5.1.  Transformation S

                S(ffeeddccbbaa99881122334455667700) = b66cd8887d38e8d77765aeea0c9a7efc,
                S(b66cd8887d38e8d77765aeea0c9a7efc) = 559d8dd7bd06cbfe7e7b262523280d39,
                S(559d8dd7bd06cbfe7e7b262523280d39) = 0c3322fed531e4630d80ef5c5a81c50b,
                S(0c3322fed531e4630d80ef5c5a81c50b) = 23ae65633f842d29c5df529c13f5acda.

5.2.  Transformation R

                R(00000000000000000000000000000100) = 94000000000000000000000000000001,
                R(94000000000000000000000000000001) = a5940000000000000000000000000000,
                R(a5940000000000000000000000000000) = 64a59400000000000000000000000000,
                R(64a59400000000000000000000000000) = 0d64a594000000000000000000000000.

5.3.  Transformation L

                L(64a59400000000000000000000000000) = d456584dd0e3e84cc3166e4b7fa2890d,
                L(d456584dd0e3e84cc3166e4b7fa2890d) = 79d26221b87b584cd42fbc4ffea5de9a,
                L(79d26221b87b584cd42fbc4ffea5de9a) = 0e93691a0cfc60408b7b68f66b513c13,
                L(0e93691a0cfc60408b7b68f66b513c13) = e6a8094fee0aa204fd97bcb0b44b8580.

Dolmatov                 Expires April 10, 2016                 [Page 8]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

5.4.  Key schedule

   In this test example, the key is equal to:

                K = 8899aabbccddeeff0011223344556677fedcba98765432100123456789abcdef.

                K_1 = 8899aabbccddeeff0011223344556677,
                K_2 = fedcba98765432100123456789abcdef.

                C_1 = 6ea276726c487ab85d27bd10dd849401,
                X[C_1](K_1) = e63bdcc9a09594475d369f2399d1f276,
                SX[C_1](K_1) = 0998ca37a7947aabb78f4a5ae81b748a,
                LSX[C_1](K_1) = 3d0940999db75d6a9257071d5e6144a6,
                F[C_1](K_1, K_2) = = (c3d5fa01ebe36f7a9374427ad7ca8949, 8899aabbccddeeff0011223344556677).

                C_2 = dc87ece4d890f4b3ba4eb92079cbeb02,
                F [C_2]F [C_1](K_1, K_2) = (37777748e56453377d5e262d90903f87, c3d5fa01ebe36f7a9374427ad7ca8949).

                C_3 = b2259a96b4d88e0be7690430a44f7f03,
                F[C_3]...F[C_1](K_1, K_2) = (f9eae5f29b2815e31f11ac5d9c29fb01, 37777748e56453377d5e262d90903f87).

                C_4 = 7bcd1b0b73e32ba5b79cb140f2551504,
                F[C_4]...F[C_1](K_1, K_2) = (e980089683d00d4be37dd3434699b98f, f9eae5f29b2815e31f11ac5d9c29fb01).

                C_5 = 156f6d791fab511deabb0c502fd18105,
                F[C_5]...F[C_1](K_1, K_2) = (b7bd70acea4460714f4ebe13835cf004, e980089683d00d4be37dd3434699b98f).

                C_6 = a74af7efab73df160dd208608b9efe06,
                F[C_6]...F[C_1](K_1, K_2) = (1a46ea1cf6ccd236467287df93fdf974, b7bd70acea4460714f4ebe13835cf004).

                C_7 = c9e8819dc73ba5ae50f5b570561a6a07,
                F[C_7]...F [C_1](K_1, K_2) = (3d4553d8e9cfec6815ebadc40a9ffd04, 1a46ea1cf6ccd236467287df93fdf974).

                C_8 = f6593616e6055689adfba18027aa2a08,
                (K_3, K_4) = F [C_8]...F [C_1](K_1, K_2) = (db31485315694343228d6aef8cc78c44, 3d4553d8e9cfec6815ebadc40a9ffd04).

   The round keys K_i, i = 1, 2, ..., 10, take the following values:

                   K_1 = 8899aabbccddeeff0011223344556677,
                   K_2 = fedcba98765432100123456789abcdef,
                   K_3 = db31485315694343228d6aef8cc78c44,
                   K_4 = 3d4553d8e9cfec6815ebadc40a9ffd04,
                   K_5 = 57646468c44a5e28d3e59246f429f1ac,
                   K_6 = bd079435165c6432b532e82834da581b,
                   K_7 = 51e640757e8745de705727265a0098b1,
                   K_8 = 5a7925017b9fdd3ed72a91a22286f984,
                   K_9 = bb44e25378c73123a5f32f73cdb6e517,
                   K_10 = 72e9dd7416bcf45b755dbaa88e4a4043.

Dolmatov                 Expires April 10, 2016                 [Page 9]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

5.5.  Test encryption

   In this test example, encryption is performed on the round keys
   specified in clause 5.4.  Let the plaintext be

                   a = 1122334455667700ffeeddccbbaa9988,

   then

                X[K_1](a) = 99bb99ff99bb99ffffffffffffffffff,
                SX[K_1](a) = e87de8b6e87de8b6b6b6b6b6b6b6b6b6,
                LSX[K_1](a) = e297b686e355b0a1cf4a2f9249140830,
                LSX[K_2]LSX[K_1](a) = 285e497a0862d596b36f4258a1c69072,
                LSX[K_3]...LSX[K_1](a) = 0187a3a429b567841ad50d29207cc34e,
                LSX[K_4]...LSX[K_1](a) = ec9bdba057d4f4d77c5d70619dcad206,
                LSX[K_5]...LSX[K_1](a) = 1357fd11de9257290c2a1473eb6bcde1,
                LSX[K_6]...LSX[K_1](a) = 28ae31e7d4c2354261027ef0b32897df,
                LSX[K_7]...LSX[K_1](a) = 07e223d56002c013d3f5e6f714b86d2d,
                LSX[K_8]...LSX[K_1](a) = cd8ef6cd97e0e092a8e4cca61b38bf65,
                LSX[K_9]...LSX[K_1](a) = 0d8e40e4a800d06b2f1b37ea379ead8e.

   Then the ciphertext is

                b = X[K_10]LSX[K_9]...LSX[K_1](a) = 7f679d90bebc24305a468d42b9d4edcd.

5.6.  Test decryption

   In this test example, decryption is performed on the round keys
   specified in clause 5.4.  Let the ciphertext be

                   b = 7f679d90bebc24305a468d42b9d4edcd,

   then

                X[K_10](b) = 0d8e40e4a800d06b2f1b37ea379ead8e,
                L^(-1)X[K_10](b) = 8a6b930a52211b45c5baa43ff8b91319,
                S^(-1)L^(-1)X[K_10](b) = 76ca149eef27d1b10d17e3d5d68e5a72,
                S^(-1)L^(-1)X[K_9]S^(-1)L^(-1)X[K_10](b) = 5d9b06d41b9d1d2d04df7755363e94a9,
                S^(-1)L^(-1)X[K_8]...S^(-1)L^(-1)X[K_10](b) = 79487192aa45709c115559d6e9280f6e,
                S^(-1)L^(-1)X[K_7]...S^(-1)L^(-1)X[K_10](b) = ae506924c8ce331bb918fc5bdfb195fa,
                S^(-1)L^(-1)X[K_6]...S^(-1)L^(-1)X[K_10](b) = bbffbfc8939eaaffafb8e22769e323aa,
                S^(-1)L^(-1)X[K_5]...S^(-1)L^(-1)X[K_10](b) = 3cc2f07cc07a8bec0f3ea0ed2ae33e4a,
                S^(-1)L^(-1)X[K_4]...S^(-1)L^(-1)X[K_10](b) = f36f01291d0b96d591e228b72d011c36,
                S^(-1)L^(-1)X[K_3]...S^(-1)L^(-1)X[K_10](b) = 1c4b0c1e950182b1ce696af5c0bfc5df,
                S^(-1)L^(-1)X[K_2]...S^(-1)L^(-1)X[K_10](b) = 99bb99ff99bb99ffffffffffffffffff.

   Then the plaintext is

Dolmatov                 Expires April 10, 2016                [Page 10]
Internet-DraftGOST R 34.12-2015: Block Cipher "Kuznyechik"  October 2015

                a = X[K_1]S^(-1)L^(-1)X[K_2]...S^(-1)L^(-1)X[K_10](b) = 1122334455667700ffeeddccbbaa9988.

6.  Security Considerations

   This entire document is about security considerations.

7.  References

7.1.  Normative References

   [GOST3412-2015]
              Federal Agency on Technical Regulating and Metrology,
              "Information technology.  Cryptographic data security.
              Block ciphers.GOST R 34.12-2015", 2015.

7.2.  Informative References

   [ISO-IEC10116]
              ISO-IEC, "Information technology - Security techniques -
              Modes of operation for an n-bit block cipher, ISO-IEC
              10116", 2006.

   [ISO-IEC18033-1]
              ISO-IEC, "Information technology - Security techniques -
              Encryption algorithms - Part 1: General, ISO-IEC 18033-1",
              2013.

   [ISO-IEC18033-3]
              ISO-IEC, "Information technology - Security techniques -
              Encryption algorithms - Part 3: Block ciphers, ISO-IEC
              18033-3", 2010.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", RFC 2119, BCP 14, March 1997.

Author's Address

   Vasily Dolmatov (editor)
   Research Computer Center M.V. Lomonosov Moscow State University
   Leninskiye Gory, 1, building 4, MGU NIVC
   Moscow  119991
   Russian Federation

   Email: dol@srcc.msu.ru

Dolmatov                 Expires April 10, 2016                [Page 11]