1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
* IDEA
* (C) 1999-2010,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/idea.h>
#include <botan/loadstor.h>
#include <botan/cpuid.h>
#include <botan/internal/ct_utils.h>
namespace Botan {
namespace {
/*
* Multiplication modulo 65537
*/
inline uint16_t mul(uint16_t x, uint16_t y)
{
const uint32_t P = static_cast<uint32_t>(x) * y;
const uint16_t Z_mask = static_cast<uint16_t>(CT::expand_mask(P) & 0xFFFF);
const uint32_t P_hi = P >> 16;
const uint32_t P_lo = P & 0xFFFF;
const uint16_t r_1 = static_cast<uint16_t>((P_lo - P_hi) + (P_lo < P_hi));
const uint16_t r_2 = 1 - x - y;
return CT::select(Z_mask, r_1, r_2);
}
/*
* Find multiplicative inverses modulo 65537
*
* 65537 is prime; thus Fermat's little theorem tells us that
* x^65537 == x modulo 65537, which means
* x^(65537-2) == x^-1 modulo 65537 since
* x^(65537-2) * x == 1 mod 65537
*
* Do the exponentiation with a basic square and multiply: all bits are
* of exponent are 1 so we always multiply
*/
uint16_t mul_inv(uint16_t x)
{
uint16_t y = x;
for(size_t i = 0; i != 15; ++i)
{
y = mul(y, y); // square
y = mul(y, x);
}
return y;
}
/**
* IDEA is involutional, depending only on the key schedule
*/
void idea_op(const uint8_t in[], uint8_t out[], size_t blocks, const uint16_t K[52])
{
const size_t BLOCK_SIZE = 8;
CT::poison(in, blocks * 8);
CT::poison(out, blocks * 8);
CT::poison(K, 52);
BOTAN_PARALLEL_FOR(size_t i = 0; i < blocks; ++i)
{
uint16_t X1, X2, X3, X4;
load_be(in + BLOCK_SIZE*i, X1, X2, X3, X4);
for(size_t j = 0; j != 8; ++j)
{
X1 = mul(X1, K[6*j+0]);
X2 += K[6*j+1];
X3 += K[6*j+2];
X4 = mul(X4, K[6*j+3]);
uint16_t T0 = X3;
X3 = mul(X3 ^ X1, K[6*j+4]);
uint16_t T1 = X2;
X2 = mul((X2 ^ X4) + X3, K[6*j+5]);
X3 += X2;
X1 ^= X2;
X4 ^= X3;
X2 ^= T0;
X3 ^= T1;
}
X1 = mul(X1, K[48]);
X2 += K[50];
X3 += K[49];
X4 = mul(X4, K[51]);
store_be(out + BLOCK_SIZE*i, X1, X3, X2, X4);
}
CT::unpoison(in, blocks * 8);
CT::unpoison(out, blocks * 8);
CT::unpoison(K, 52);
}
}
size_t IDEA::parallelism() const
{
#if defined(BOTAN_HAS_IDEA_SSE2)
if(CPUID::has_sse2())
{
return 8;
}
#endif
return 1;
}
std::string IDEA::provider() const
{
#if defined(BOTAN_HAS_IDEA_SSE2)
if(CPUID::has_sse2())
{
return "sse2";
}
#endif
return "base";
}
/*
* IDEA Encryption
*/
void IDEA::encrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const
{
#if defined(BOTAN_HAS_IDEA_SSE2)
if(CPUID::has_sse2())
{
while(blocks >= 8)
{
sse2_idea_op_8(in, out, m_EK.data());
in += 8 * BLOCK_SIZE;
out += 8 * BLOCK_SIZE;
blocks -= 8;
}
}
#endif
idea_op(in, out, blocks, m_EK.data());
}
/*
* IDEA Decryption
*/
void IDEA::decrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const
{
#if defined(BOTAN_HAS_IDEA_SSE2)
if(CPUID::has_sse2())
{
while(blocks >= 8)
{
sse2_idea_op_8(in, out, m_DK.data());
in += 8 * BLOCK_SIZE;
out += 8 * BLOCK_SIZE;
blocks -= 8;
}
}
#endif
idea_op(in, out, blocks, m_DK.data());
}
/*
* IDEA Key Schedule
*/
void IDEA::key_schedule(const uint8_t key[], size_t)
{
m_EK.resize(52);
m_DK.resize(52);
CT::poison(key, 16);
CT::poison(m_EK.data(), 52);
CT::poison(m_DK.data(), 52);
for(size_t i = 0; i != 8; ++i)
m_EK[i] = load_be<uint16_t>(key, i);
for(size_t i = 1, j = 8, offset = 0; j != 52; i %= 8, ++i, ++j)
{
m_EK[i+7+offset] = static_cast<uint16_t>((m_EK[(i % 8) + offset] << 9) |
(m_EK[((i+1) % 8) + offset] >> 7));
offset += (i == 8) ? 8 : 0;
}
m_DK[51] = mul_inv(m_EK[3]);
m_DK[50] = -m_EK[2];
m_DK[49] = -m_EK[1];
m_DK[48] = mul_inv(m_EK[0]);
for(size_t i = 1, j = 4, counter = 47; i != 8; ++i, j += 6)
{
m_DK[counter--] = m_EK[j+1];
m_DK[counter--] = m_EK[j];
m_DK[counter--] = mul_inv(m_EK[j+5]);
m_DK[counter--] = -m_EK[j+3];
m_DK[counter--] = -m_EK[j+4];
m_DK[counter--] = mul_inv(m_EK[j+2]);
}
m_DK[5] = m_EK[47];
m_DK[4] = m_EK[46];
m_DK[3] = mul_inv(m_EK[51]);
m_DK[2] = -m_EK[50];
m_DK[1] = -m_EK[49];
m_DK[0] = mul_inv(m_EK[48]);
CT::unpoison(key, 16);
CT::unpoison(m_EK.data(), 52);
CT::unpoison(m_DK.data(), 52);
}
void IDEA::clear()
{
zap(m_EK);
zap(m_DK);
}
}
|
