Botan 1.10.17

seed.cpp
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1 /*
2 * SEED
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7
8 #include <botan/seed.h>
9 #include <botan/loadstor.h>
10
11 namespace Botan {
12
13 /*
14 * SEED G Function
15 */
16 u32bit SEED::G_FUNC::operator()(u32bit X) const
17 {
18 return (S0[get_byte(3, X)] ^ S1[get_byte(2, X)] ^
19 S2[get_byte(1, X)] ^ S3[get_byte(0, X)]);
20 }
21
22 /*
23 * SEED Encryption
24 */
25 void SEED::encrypt_n(const byte in[], byte out[], size_t blocks) const
26 {
27 for(size_t i = 0; i != blocks; ++i)
28 {
29 u32bit B0 = load_be<u32bit>(in, 0);
30 u32bit B1 = load_be<u32bit>(in, 1);
31 u32bit B2 = load_be<u32bit>(in, 2);
32 u32bit B3 = load_be<u32bit>(in, 3);
33
34 G_FUNC G;
35
36 for(size_t j = 0; j != 16; j += 2)
37 {
38 u32bit T0, T1;
39
40 T0 = B2 ^ K[2*j];
41 T1 = G(B2 ^ B3 ^ K[2*j+1]);
42 T0 = G(T1 + T0);
43 T1 = G(T1 + T0);
44 B1 ^= T1;
45 B0 ^= T0 + T1;
46
47 T0 = B0 ^ K[2*j+2];
48 T1 = G(B0 ^ B1 ^ K[2*j+3]);
49 T0 = G(T1 + T0);
50 T1 = G(T1 + T0);
51 B3 ^= T1;
52 B2 ^= T0 + T1;
53 }
54
55 store_be(out, B2, B3, B0, B1);
56
57 in += BLOCK_SIZE;
58 out += BLOCK_SIZE;
59 }
60 }
61
62 /*
63 * SEED Decryption
64 */
65 void SEED::decrypt_n(const byte in[], byte out[], size_t blocks) const
66 {
67 for(size_t i = 0; i != blocks; ++i)
68 {
69 u32bit B0 = load_be<u32bit>(in, 0);
70 u32bit B1 = load_be<u32bit>(in, 1);
71 u32bit B2 = load_be<u32bit>(in, 2);
72 u32bit B3 = load_be<u32bit>(in, 3);
73
74 G_FUNC G;
75
76 for(size_t j = 0; j != 16; j += 2)
77 {
78 u32bit T0, T1;
79
80 T0 = B2 ^ K[30-2*j];
81 T1 = G(B2 ^ B3 ^ K[31-2*j]);
82 T0 = G(T1 + T0);
83 T1 = G(T1 + T0);
84 B1 ^= T1;
85 B0 ^= T0 + T1;
86
87 T0 = B0 ^ K[28-2*j];
88 T1 = G(B0 ^ B1 ^ K[29-2*j]);
89 T0 = G(T1 + T0);
90 T1 = G(T1 + T0);
91 B3 ^= T1;
92 B2 ^= T0 + T1;
93 }
94
95 store_be(out, B2, B3, B0, B1);
96
97 in += BLOCK_SIZE;
98 out += BLOCK_SIZE;
99 }
100 }
101
102 /*
103 * SEED Key Schedule
104 */
105 void SEED::key_schedule(const byte key[], size_t)
106 {
107 const u32bit RC[16] = {
108 0x9E3779B9, 0x3C6EF373, 0x78DDE6E6, 0xF1BBCDCC,
109 0xE3779B99, 0xC6EF3733, 0x8DDE6E67, 0x1BBCDCCF,
110 0x3779B99E, 0x6EF3733C, 0xDDE6E678, 0xBBCDCCF1,
111 0x779B99E3, 0xEF3733C6, 0xDE6E678D, 0xBCDCCF1B
112 };
113
114 SecureVector<u32bit> WK(4);
115
116 for(size_t i = 0; i != 4; ++i)
117 WK[i] = load_be<u32bit>(key, i);
118
119 G_FUNC G;
120
121 for(size_t i = 0; i != 16; i += 2)
122 {
123 K[2*i ] = G(WK[0] + WK[2] - RC[i]);
124 K[2*i+1] = G(WK[1] - WK[3] + RC[i]) ^ K[2*i];
125
126 byte T = get_byte(3, WK[0]);
127 WK[0] = (WK[0] >> 8) | (get_byte(3, WK[1]) << 24);
128 WK[1] = (WK[1] >> 8) | (T << 24);
129
130 K[2*i+2] = G(WK[0] + WK[2] - RC[i+1]);
131 K[2*i+3] = G(WK[1] - WK[3] + RC[i+1]) ^ K[2*i+2];
132
133 T = get_byte(0, WK[3]);
134 WK[3] = (WK[3] << 8) | get_byte(0, WK[2]);
135 WK[2] = (WK[2] << 8) | T;
136 }
137 }
138
139 }
Botan::Block_Cipher_Fixed_Params< 16, 16 >::BLOCK_SIZE
Definition: block_cipher.h:107
Botan::SEED::encrypt_n
void encrypt_n(const byte in[], byte out[], size_t blocks) const
Definition: seed.cpp:25
Botan::get_byte
byte get_byte(size_t byte_num, T input)
Definition: get_byte.h:21
Botan::byte
unsigned char byte
Definition: types.h:22
Botan
Definition: algo_base.h:14
Botan::load_be< u32bit >
u32bit load_be< u32bit >(const byte in[], size_t off)
Definition: loadstor.h:166
Botan::SEED::decrypt_n
void decrypt_n(const byte in[], byte out[], size_t blocks) const
Definition: seed.cpp:65
Botan::store_be
void store_be(u16bit in, byte out[2])
Definition: loadstor.h:412
Botan::u32bit
unsigned int u32bit
Definition: types.h:32