Crypto++  5.6.4
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 
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
Utility functions for the Crypto++ library.
Classes for the GIST block cipher.
Access a block of memory.
Definition: misc.h:2255
byte order is little-endian
Definition: cryptlib.h:130
GOST block cipher.
Definition: gost.h:24
Access a block of memory.
Definition: misc.h:2217
Crypto++ library namespace.
T rotlMod(T x, unsigned int y)
Performs a left rotate.
Definition: misc.h:1391
Interface for retrieving values given their names.
Definition: cryptlib.h:282