Crypto++ 8.5 Free C++ class library of cryptographic schemes

gost.cpp
1 #include "pch.h"
2 #include "gost.h"
3 #include "misc.h"
4
5 NAMESPACE_BEGIN(CryptoPP)
6
7 // these are the S-boxes given in Applied Cryptography 2nd Ed., p. 333
8 const byte GOST::Base::sBox[8][16]={
9 {4, 10, 9, 2, 13, 8, 0, 14, 6, 11, 1, 12, 7, 15, 5, 3},
10 {14, 11, 4, 12, 6, 13, 15, 10, 2, 3, 8, 1, 0, 7, 5, 9},
11 {5, 8, 1, 13, 10, 3, 4, 2, 14, 15, 12, 7, 6, 0, 9, 11},
12 {7, 13, 10, 1, 0, 8, 9, 15, 14, 4, 6, 12, 11, 2, 5, 3},
13 {6, 12, 7, 1, 5, 15, 13, 8, 4, 10, 9, 14, 0, 3, 11, 2},
14 {4, 11, 10, 0, 7, 2, 1, 13, 3, 6, 8, 5, 9, 12, 15, 14},
15 {13, 11, 4, 1, 3, 15, 5, 9, 0, 10, 14, 7, 6, 8, 2, 12},
16 {1, 15, 13, 0, 5, 7, 10, 4, 9, 2, 3, 14, 6, 11, 8, 12}};
17
18 /* // these are the S-boxes given in the GOST source code listing in Applied
19 // Cryptography 2nd Ed., p. 644. they appear to be from the DES S-boxes
20 {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7 },
21 { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1 },
22 {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11 },
23 { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9 },
24 { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15 },
25 {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8 },
26 {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10 },
27 {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7 }};
28 */
29
30 volatile bool GOST::Base::sTableCalculated = false;
31 word32 GOST::Base::sTable[4][256];
32
33 void GOST::Base::UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &)
34 {
35 AssertValidKeyLength(length);
36
37 PrecalculateSTable();
38
39 GetUserKey(LITTLE_ENDIAN_ORDER, m_key.begin(), 8, userKey, KEYLENGTH);
40 }
41
42 void GOST::Base::PrecalculateSTable()
43 {
44 if (!sTableCalculated)
45 {
46 for (unsigned i = 0; i < 4; i++)
47 for (unsigned j = 0; j < 256; j++)
48 {
49 word32 temp = sBox[2*i][j%16] | (sBox[2*i+1][j/16] << 4);
50 sTable[i][j] = rotlMod(temp, 11+8*i);
51 }
52
53 sTableCalculated=true;
54 }
55 }
56
57 #define f(x) ( t=x, \
58 sTable[3][GETBYTE(t, 3)] ^ sTable[2][GETBYTE(t, 2)] \
59 ^ sTable[1][GETBYTE(t, 1)] ^ sTable[0][GETBYTE(t, 0)] )
60
61 typedef BlockGetAndPut<word32, LittleEndian> Block;
62
63 void GOST::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
64 {
65 word32 n1, n2, t;
66
67 Block::Get(inBlock)(n1)(n2);
68
69 for (unsigned int i=0; i<3; i++)
70 {
71 n2 ^= f(n1+m_key[0]);
72 n1 ^= f(n2+m_key[1]);
73 n2 ^= f(n1+m_key[2]);
74 n1 ^= f(n2+m_key[3]);
75 n2 ^= f(n1+m_key[4]);
76 n1 ^= f(n2+m_key[5]);
77 n2 ^= f(n1+m_key[6]);
78 n1 ^= f(n2+m_key[7]);
79 }
80
81 n2 ^= f(n1+m_key[7]);
82 n1 ^= f(n2+m_key[6]);
83 n2 ^= f(n1+m_key[5]);
84 n1 ^= f(n2+m_key[4]);
85 n2 ^= f(n1+m_key[3]);
86 n1 ^= f(n2+m_key[2]);
87 n2 ^= f(n1+m_key[1]);
88 n1 ^= f(n2+m_key[0]);
89
90 Block::Put(xorBlock, outBlock)(n2)(n1);
91 }
92
93 void GOST::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
94 {
95 word32 n1, n2, t;
96
97 Block::Get(inBlock)(n1)(n2);
98
99 n2 ^= f(n1+m_key[0]);
100 n1 ^= f(n2+m_key[1]);
101 n2 ^= f(n1+m_key[2]);
102 n1 ^= f(n2+m_key[3]);
103 n2 ^= f(n1+m_key[4]);
104 n1 ^= f(n2+m_key[5]);
105 n2 ^= f(n1+m_key[6]);
106 n1 ^= f(n2+m_key[7]);
107
108 for (unsigned int i=0; i<3; i++)
109 {
110 n2 ^= f(n1+m_key[7]);
111 n1 ^= f(n2+m_key[6]);
112 n2 ^= f(n1+m_key[5]);
113 n1 ^= f(n2+m_key[4]);
114 n2 ^= f(n1+m_key[3]);
115 n1 ^= f(n2+m_key[2]);
116 n2 ^= f(n1+m_key[1]);
117 n1 ^= f(n2+m_key[0]);
118 }
119
120 Block::Put(xorBlock, outBlock)(n2)(n1);
121 }
122
123 NAMESPACE_END
rotlMod
T rotlMod(T x, unsigned int y)
Performs a left rotate.
Definition: misc.h:1664
LITTLE_ENDIAN_ORDER
@ LITTLE_ENDIAN_ORDER
byte order is little-endian
Definition: cryptlib.h:145
pch.h
Precompiled header file.
word32
unsigned int word32
32-bit unsigned datatype
Definition: config_int.h:62
misc.h
Utility functions for the Crypto++ library.
PutBlock
Access a block of memory.
Definition: misc.h:2549
BlockGetAndPut
Access a block of memory.
Definition: misc.h:2586
CryptoPP
Crypto++ library namespace.
gost.h
Classes for the GIST block cipher.
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:321