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1 : : /* ykaes.c --- Implementation of AES-128.
2 : : *
3 : : * Copyright (c) 2006, 2007, 2008, 2009 Yubico AB
4 : : * All rights reserved.
5 : : *
6 : : * Redistribution and use in source and binary forms, with or without
7 : : * modification, are permitted provided that the following conditions are
8 : : * met:
9 : : *
10 : : * * Redistributions of source code must retain the above copyright
11 : : * notice, this list of conditions and the following disclaimer.
12 : : *
13 : : * * Redistributions in binary form must reproduce the above
14 : : * copyright notice, this list of conditions and the following
15 : : * disclaimer in the documentation and/or other materials provided
16 : : * with the distribution.
17 : : *
18 : : * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 : : * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 : : * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 : : * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 : : * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 : : * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 : : * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 : : * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 : : * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 : : * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 : : * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 : : *
30 : : */
31 : :
32 : : #include "yubikey.h"
33 : :
34 : : #define NUMBER_OF_ROUNDS 10
35 : :
36 : : static const unsigned char RC[] =
37 : : { 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36 };
38 : :
39 : : static const unsigned char rijndael_sbox[] = {
40 : : 0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5,
41 : : 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
42 : : 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
43 : : 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
44 : : 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC,
45 : : 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
46 : : 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A,
47 : : 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
48 : : 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
49 : : 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
50 : : 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B,
51 : : 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
52 : : 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85,
53 : : 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
54 : : 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
55 : : 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
56 : : 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17,
57 : : 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
58 : : 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88,
59 : : 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
60 : : 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
61 : : 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
62 : : 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9,
63 : : 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
64 : : 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6,
65 : : 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
66 : : 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
67 : : 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
68 : : 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94,
69 : : 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
70 : : 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
71 : : 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
72 : : };
73 : :
74 : : static const unsigned char rijndael_inv_sbox[] = {
75 : : 0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38,
76 : : 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
77 : : 0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87,
78 : : 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
79 : : 0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D,
80 : : 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
81 : : 0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2,
82 : : 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
83 : : 0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16,
84 : : 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
85 : : 0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA,
86 : : 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
87 : : 0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A,
88 : : 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
89 : : 0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02,
90 : : 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
91 : : 0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA,
92 : : 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
93 : : 0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85,
94 : : 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
95 : : 0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89,
96 : : 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
97 : : 0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20,
98 : : 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
99 : : 0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31,
100 : : 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
101 : : 0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D,
102 : : 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
103 : : 0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0,
104 : : 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
105 : : 0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26,
106 : : 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
107 : : };
108 : :
109 : : /* Called by: yubikey_aes_decrypt x7 */
110 : : static /*inline*/ unsigned char
111 : : xtime (unsigned char b)
112 : 0 : {
113 [ # # ]: 0 : return (b & 0x80) ? ((b << 1) ^ 0x1b) : (b << 1);
114 : : }
115 : :
116 : : /* Called by: main, zxid_pw_authn */
117 : : void
118 : : yubikey_aes_decrypt (unsigned char * state, const unsigned char * key)
119 : 0 : {
120 : : unsigned char i, j, round_key[0x10];
121 : : unsigned char a02x, a13x;
122 : : unsigned char a02xx, a13xx;
123 : : unsigned char k1, k2;
124 : :
125 : 0 : memcpy (round_key, key, sizeof (round_key));
126 [ # # ]: 0 : for (i = 0; i < NUMBER_OF_ROUNDS; i++)
127 : : {
128 : 0 : round_key[0] ^= RC[i];
129 : :
130 : 0 : round_key[0] ^= rijndael_sbox[round_key[13]];
131 : 0 : round_key[1] ^= rijndael_sbox[round_key[14]];
132 : 0 : round_key[2] ^= rijndael_sbox[round_key[15]];
133 : 0 : round_key[3] ^= rijndael_sbox[round_key[12]];
134 : :
135 [ # # ]: 0 : for (j = 4; j < 16; j++)
136 : 0 : round_key[j] ^= round_key[j - 4];
137 : : }
138 [ # # ]: 0 : for (i = 0; i < 0x10; i++)
139 : 0 : state[i] ^= round_key[i];
140 : :
141 [ # # ]: 0 : for (i = 1; i <= NUMBER_OF_ROUNDS; i++)
142 : : {
143 : : // inv_byte_sub_shift_row();
144 : :
145 : : /* First row: 0 shift, 0 4 8 12 */
146 : 0 : state[0] = rijndael_inv_sbox[state[0]];
147 : 0 : state[4] = rijndael_inv_sbox[state[4]];
148 : 0 : state[8] = rijndael_inv_sbox[state[8]];
149 : 0 : state[12] = rijndael_inv_sbox[state[12]];
150 : :
151 : : /* Second row: -1 shift, 1 5 9 13 */
152 : 0 : j = state[13];
153 : 0 : state[13] = rijndael_inv_sbox[state[9]];
154 : 0 : state[9] = rijndael_inv_sbox[state[5]];
155 : 0 : state[5] = rijndael_inv_sbox[state[1]];
156 : 0 : state[1] = rijndael_inv_sbox[j];
157 : :
158 : : /* Third row: -2 shift, 2 6 10 14 */
159 : 0 : j = state[2];
160 : 0 : state[2] = rijndael_inv_sbox[state[10]];
161 : 0 : state[10] = rijndael_inv_sbox[j];
162 : 0 : j = state[6];
163 : 0 : state[6] = rijndael_inv_sbox[state[14]];
164 : 0 : state[14] = rijndael_inv_sbox[j];
165 : :
166 : : /* Fourth row: -3 shift, 3 7 11 15 */
167 : 0 : j = state[3];
168 : 0 : state[3] = rijndael_inv_sbox[state[7]];
169 : 0 : state[7] = rijndael_inv_sbox[state[11]];
170 : 0 : state[11] = rijndael_inv_sbox[state[15]];
171 : 0 : state[15] = rijndael_inv_sbox[j];
172 : :
173 : : // get_inv_round_key(i);
174 : :
175 [ # # ]: 0 : for (j = 15; j > 3; j--)
176 : 0 : round_key[j] ^= round_key[j - 4];
177 : :
178 : 0 : round_key[0] ^=
179 : : (RC[NUMBER_OF_ROUNDS - i] ^ rijndael_sbox[round_key[13]]);
180 : :
181 : 0 : round_key[1] ^= rijndael_sbox[round_key[14]];
182 : 0 : round_key[2] ^= rijndael_sbox[round_key[15]];
183 : 0 : round_key[3] ^= rijndael_sbox[round_key[12]];
184 : :
185 [ # # ]: 0 : for (j = 0; j < 16; j++)
186 : 0 : state[j] ^= round_key[j];
187 [ # # ]: 0 : if (i != NUMBER_OF_ROUNDS)
188 : : {
189 : :
190 : : //inv_mix_column();
191 : :
192 [ # # ]: 0 : for (j = 0; j < 16; j += 4)
193 : : {
194 : 0 : k1 = state[j] ^ state[j + 2];
195 : 0 : a02x = xtime (k1);
196 : 0 : k2 = state[j + 1] ^ state[j + 3];
197 : 0 : a13x = xtime (k2);
198 : :
199 : 0 : k1 ^= (k2 ^ xtime (state[j + 1] ^ state[j + 2]));
200 : 0 : k2 = k1;
201 : :
202 : 0 : a02xx = xtime (a02x);
203 : 0 : a13xx = xtime (a13x);
204 : :
205 : 0 : k1 ^= (xtime (a02xx ^ a13xx) ^ a02xx);
206 : 0 : k2 ^= (xtime (a02xx ^ a13xx) ^ a13xx);
207 : :
208 : 0 : state[j] ^= (k1 ^ a02x);
209 : 0 : state[j + 1] ^= k2;
210 : 0 : state[j + 2] ^= (k1 ^ a13x);
211 : 0 : state[j + 3] ^= (k2 ^ a02x ^ a13x);
212 : : }
213 : : }
214 : :
215 : : }
216 : 0 : }
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