-
Notifications
You must be signed in to change notification settings - Fork 20
/
Copy pathxtea.cpp
140 lines (120 loc) · 4.76 KB
/
xtea.cpp
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
/**
* The Forgotten Server - a free and open-source MMORPG server emulator
* Copyright (C) 2019 Mark Samman <mark.samman@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "otpch.h"
#include "xtea.h"
#include <array>
#include <assert.h>
namespace xtea {
namespace {
constexpr uint32_t delta = 0x9E3779B9;
template<size_t BLOCK_SIZE>
void XTEA_encrypt(uint8_t data[BLOCK_SIZE * 8], const key& k)
{
alignas(16) uint32_t left[BLOCK_SIZE], right[BLOCK_SIZE];
for (auto i = 0u, j = 0u; i < BLOCK_SIZE; i += 1u, j += 8u) {
left[i] = data[j] | data[j+1] << 8u | data[j+2] << 16u | data[j+3] << 24u;
right[i] = data[j+4] | data[j+5] << 8u | data[j+6] << 16u | data[j+7] << 24u;
}
uint32_t sum = 0u;
for (auto i = 0u; i < 32; ++i) {
for (auto j = 0u; j < BLOCK_SIZE; ++j) {
left[j] += (((right[j] << 4) ^ (right[j] >> 5)) + right[j]) ^ (sum + k[sum & 3]);
}
sum += delta;
for (auto j = 0u; j < BLOCK_SIZE; ++j) {
right[j] += (((left[j] << 4) ^ (left[j] >> 5)) + left[j]) ^ (sum + k[(sum >> 11) & 3]);
}
}
for (auto i = 0u, j = 0u; i < BLOCK_SIZE; i += 1u, j += 8u) {
data[j] = static_cast<uint8_t>(left[i]);
data[j+1] = static_cast<uint8_t>(left[i] >> 8u);
data[j+2] = static_cast<uint8_t>(left[i] >> 16u);
data[j+3] = static_cast<uint8_t>(left[i] >> 24u);
data[j+4] = static_cast<uint8_t>(right[i]);
data[j+5] = static_cast<uint8_t>(right[i] >> 8u);
data[j+6] = static_cast<uint8_t>(right[i] >> 16u);
data[j+7] = static_cast<uint8_t>(right[i] >> 24u);
}
}
template<size_t BLOCK_SIZE>
void XTEA_decrypt(uint8_t data[BLOCK_SIZE * 8], const key& k)
{
alignas(16) uint32_t left[BLOCK_SIZE], right[BLOCK_SIZE];
for (auto i = 0u, j = 0u; i < BLOCK_SIZE; i += 1u, j += 8u) {
left[i] = data[j] | data[j+1] << 8u | data[j+2] << 16u | data[j+3] << 24u;
right[i] = data[j+4] | data[j+5] << 8u | data[j+6] << 16u | data[j+7] << 24u;
}
uint32_t sum = delta << 5;
for (auto i = 0u; i < 32; ++i) {
for (auto j = 0u; j < BLOCK_SIZE; ++j) {
right[j] -= (((left[j] << 4) ^ (left[j] >> 5)) + left[j]) ^ (sum + k[(sum >> 11) & 3]);
}
sum -= delta;
for (auto j = 0u; j < BLOCK_SIZE; ++j) {
left[j] -= (((right[j] << 4) ^ (right[j] >> 5)) + right[j]) ^ (sum + k[(sum) & 3]);
}
}
for (auto i = 0u, j = 0u; i < BLOCK_SIZE; i += 1u, j += 8u) {
data[j] = static_cast<uint8_t>(left[i]);
data[j+1] = static_cast<uint8_t>(left[i] >> 8u);
data[j+2] = static_cast<uint8_t>(left[i] >> 16u);
data[j+3] = static_cast<uint8_t>(left[i] >> 24u);
data[j+4] = static_cast<uint8_t>(right[i]);
data[j+5] = static_cast<uint8_t>(right[i] >> 8u);
data[j+6] = static_cast<uint8_t>(right[i] >> 16u);
data[j+7] = static_cast<uint8_t>(right[i] >> 24u);
}
}
constexpr auto InitialBlockSize =
#if defined(__AVX512F__)
128u;
#elif defined(__AVX__)
32u;
#elif defined(__SSE__) || defined(__ARM_FEATURE_SIMD32)
8u;
#elif defined(__x86_64__)
2u;
#else
1u;
#endif
template<bool Encrypt, size_t BlockSize>
struct XTEA {
static constexpr auto step = BlockSize * 8u;
void operator()(uint8_t* input, size_t length, const key& k) const {
const auto blocks = (length & ~(step - 1));
for (auto i = 0u; i < blocks; i += step) {
if (Encrypt) {
XTEA_encrypt<BlockSize>(input + i, k);
} else {
XTEA_decrypt<BlockSize>(input + i, k);
}
}
input += blocks;
length -= blocks;
if (BlockSize != 1) {
XTEA<Encrypt, (BlockSize + 1u) / 2u>()(input, length, k);
}
}
};
constexpr auto encrypt_v = XTEA<true, InitialBlockSize>();
constexpr auto decrypt_v = XTEA<false, InitialBlockSize>();
} // anonymous namespace
void encrypt(uint8_t* data, size_t length, const key& k) { encrypt_v(data, length, k); }
void decrypt(uint8_t* data, size_t length, const key& k) { decrypt_v(data, length, k); }
} // namespace xtea