1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /*
28 * Inverse S-box (used in key schedule for decryption).
29 */
30 static const unsigned char iS[] = {
31 0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E,
32 0x81, 0xF3, 0xD7, 0xFB, 0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87,
33 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB, 0x54, 0x7B, 0x94, 0x32,
34 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
35 0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49,
36 0x6D, 0x8B, 0xD1, 0x25, 0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16,
37 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92, 0x6C, 0x70, 0x48, 0x50,
38 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
39 0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05,
40 0xB8, 0xB3, 0x45, 0x06, 0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02,
41 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B, 0x3A, 0x91, 0x11, 0x41,
42 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
43 0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8,
44 0x1C, 0x75, 0xDF, 0x6E, 0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89,
45 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B, 0xFC, 0x56, 0x3E, 0x4B,
46 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
47 0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59,
48 0x27, 0x80, 0xEC, 0x5F, 0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D,
49 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF, 0xA0, 0xE0, 0x3B, 0x4D,
50 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
51 0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63,
52 0x55, 0x21, 0x0C, 0x7D
53 };
54
55 static const uint32_t iSsm0[] = {
56 0x51F4A750, 0x7E416553, 0x1A17A4C3, 0x3A275E96, 0x3BAB6BCB, 0x1F9D45F1,
57 0xACFA58AB, 0x4BE30393, 0x2030FA55, 0xAD766DF6, 0x88CC7691, 0xF5024C25,
58 0x4FE5D7FC, 0xC52ACBD7, 0x26354480, 0xB562A38F, 0xDEB15A49, 0x25BA1B67,
59 0x45EA0E98, 0x5DFEC0E1, 0xC32F7502, 0x814CF012, 0x8D4697A3, 0x6BD3F9C6,
60 0x038F5FE7, 0x15929C95, 0xBF6D7AEB, 0x955259DA, 0xD4BE832D, 0x587421D3,
61 0x49E06929, 0x8EC9C844, 0x75C2896A, 0xF48E7978, 0x99583E6B, 0x27B971DD,
62 0xBEE14FB6, 0xF088AD17, 0xC920AC66, 0x7DCE3AB4, 0x63DF4A18, 0xE51A3182,
63 0x97513360, 0x62537F45, 0xB16477E0, 0xBB6BAE84, 0xFE81A01C, 0xF9082B94,
64 0x70486858, 0x8F45FD19, 0x94DE6C87, 0x527BF8B7, 0xAB73D323, 0x724B02E2,
65 0xE31F8F57, 0x6655AB2A, 0xB2EB2807, 0x2FB5C203, 0x86C57B9A, 0xD33708A5,
66 0x302887F2, 0x23BFA5B2, 0x02036ABA, 0xED16825C, 0x8ACF1C2B, 0xA779B492,
67 0xF307F2F0, 0x4E69E2A1, 0x65DAF4CD, 0x0605BED5, 0xD134621F, 0xC4A6FE8A,
68 0x342E539D, 0xA2F355A0, 0x058AE132, 0xA4F6EB75, 0x0B83EC39, 0x4060EFAA,
69 0x5E719F06, 0xBD6E1051, 0x3E218AF9, 0x96DD063D, 0xDD3E05AE, 0x4DE6BD46,
70 0x91548DB5, 0x71C45D05, 0x0406D46F, 0x605015FF, 0x1998FB24, 0xD6BDE997,
71 0x894043CC, 0x67D99E77, 0xB0E842BD, 0x07898B88, 0xE7195B38, 0x79C8EEDB,
72 0xA17C0A47, 0x7C420FE9, 0xF8841EC9, 0x00000000, 0x09808683, 0x322BED48,
73 0x1E1170AC, 0x6C5A724E, 0xFD0EFFFB, 0x0F853856, 0x3DAED51E, 0x362D3927,
74 0x0A0FD964, 0x685CA621, 0x9B5B54D1, 0x24362E3A, 0x0C0A67B1, 0x9357E70F,
75 0xB4EE96D2, 0x1B9B919E, 0x80C0C54F, 0x61DC20A2, 0x5A774B69, 0x1C121A16,
76 0xE293BA0A, 0xC0A02AE5, 0x3C22E043, 0x121B171D, 0x0E090D0B, 0xF28BC7AD,
77 0x2DB6A8B9, 0x141EA9C8, 0x57F11985, 0xAF75074C, 0xEE99DDBB, 0xA37F60FD,
78 0xF701269F, 0x5C72F5BC, 0x44663BC5, 0x5BFB7E34, 0x8B432976, 0xCB23C6DC,
79 0xB6EDFC68, 0xB8E4F163, 0xD731DCCA, 0x42638510, 0x13972240, 0x84C61120,
80 0x854A247D, 0xD2BB3DF8, 0xAEF93211, 0xC729A16D, 0x1D9E2F4B, 0xDCB230F3,
81 0x0D8652EC, 0x77C1E3D0, 0x2BB3166C, 0xA970B999, 0x119448FA, 0x47E96422,
82 0xA8FC8CC4, 0xA0F03F1A, 0x567D2CD8, 0x223390EF, 0x87494EC7, 0xD938D1C1,
83 0x8CCAA2FE, 0x98D40B36, 0xA6F581CF, 0xA57ADE28, 0xDAB78E26, 0x3FADBFA4,
84 0x2C3A9DE4, 0x5078920D, 0x6A5FCC9B, 0x547E4662, 0xF68D13C2, 0x90D8B8E8,
85 0x2E39F75E, 0x82C3AFF5, 0x9F5D80BE, 0x69D0937C, 0x6FD52DA9, 0xCF2512B3,
86 0xC8AC993B, 0x10187DA7, 0xE89C636E, 0xDB3BBB7B, 0xCD267809, 0x6E5918F4,
87 0xEC9AB701, 0x834F9AA8, 0xE6956E65, 0xAAFFE67E, 0x21BCCF08, 0xEF15E8E6,
88 0xBAE79BD9, 0x4A6F36CE, 0xEA9F09D4, 0x29B07CD6, 0x31A4B2AF, 0x2A3F2331,
89 0xC6A59430, 0x35A266C0, 0x744EBC37, 0xFC82CAA6, 0xE090D0B0, 0x33A7D815,
90 0xF104984A, 0x41ECDAF7, 0x7FCD500E, 0x1791F62F, 0x764DD68D, 0x43EFB04D,
91 0xCCAA4D54, 0xE49604DF, 0x9ED1B5E3, 0x4C6A881B, 0xC12C1FB8, 0x4665517F,
92 0x9D5EEA04, 0x018C355D, 0xFA877473, 0xFB0B412E, 0xB3671D5A, 0x92DBD252,
93 0xE9105633, 0x6DD64713, 0x9AD7618C, 0x37A10C7A, 0x59F8148E, 0xEB133C89,
94 0xCEA927EE, 0xB761C935, 0xE11CE5ED, 0x7A47B13C, 0x9CD2DF59, 0x55F2733F,
95 0x1814CE79, 0x73C737BF, 0x53F7CDEA, 0x5FFDAA5B, 0xDF3D6F14, 0x7844DB86,
96 0xCAAFF381, 0xB968C43E, 0x3824342C, 0xC2A3405F, 0x161DC372, 0xBCE2250C,
97 0x283C498B, 0xFF0D9541, 0x39A80171, 0x080CB3DE, 0xD8B4E49C, 0x6456C190,
98 0x7BCB8461, 0xD532B670, 0x486C5C74, 0xD0B85742
99 };
100
101 static unsigned
mul2(unsigned x)102 mul2(unsigned x)
103 {
104 x <<= 1;
105 return x ^ ((unsigned)(-(int)(x >> 8)) & 0x11B);
106 }
107
108 static unsigned
mul9(unsigned x)109 mul9(unsigned x)
110 {
111 return x ^ mul2(mul2(mul2(x)));
112 }
113
114 static unsigned
mulb(unsigned x)115 mulb(unsigned x)
116 {
117 unsigned x2;
118
119 x2 = mul2(x);
120 return x ^ x2 ^ mul2(mul2(x2));
121 }
122
123 static unsigned
muld(unsigned x)124 muld(unsigned x)
125 {
126 unsigned x4;
127
128 x4 = mul2(mul2(x));
129 return x ^ x4 ^ mul2(x4);
130 }
131
132 static unsigned
mule(unsigned x)133 mule(unsigned x)
134 {
135 unsigned x2, x4;
136
137 x2 = mul2(x);
138 x4 = mul2(x2);
139 return x2 ^ x4 ^ mul2(x4);
140 }
141
142 /* see inner.h */
143 unsigned
br_aes_big_keysched_inv(uint32_t * skey,const void * key,size_t key_len)144 br_aes_big_keysched_inv(uint32_t *skey, const void *key, size_t key_len)
145 {
146 unsigned num_rounds;
147 int i, m;
148
149 /*
150 * Sub-keys for decryption are distinct from encryption sub-keys
151 * in that InvMixColumns() is already applied for the inner
152 * rounds.
153 */
154 num_rounds = br_aes_keysched(skey, key, key_len);
155 m = (int)(num_rounds << 2);
156 for (i = 4; i < m; i ++) {
157 uint32_t p;
158 unsigned p0, p1, p2, p3;
159 uint32_t q0, q1, q2, q3;
160
161 p = skey[i];
162 p0 = p >> 24;
163 p1 = (p >> 16) & 0xFF;
164 p2 = (p >> 8) & 0xFF;
165 p3 = p & 0xFF;
166 q0 = mule(p0) ^ mulb(p1) ^ muld(p2) ^ mul9(p3);
167 q1 = mul9(p0) ^ mule(p1) ^ mulb(p2) ^ muld(p3);
168 q2 = muld(p0) ^ mul9(p1) ^ mule(p2) ^ mulb(p3);
169 q3 = mulb(p0) ^ muld(p1) ^ mul9(p2) ^ mule(p3);
170 skey[i] = (q0 << 24) | (q1 << 16) | (q2 << 8) | q3;
171 }
172 return num_rounds;
173 }
174
175 static inline uint32_t
rotr(uint32_t x,int n)176 rotr(uint32_t x, int n)
177 {
178 return (x << (32 - n)) | (x >> n);
179 }
180
181 #define iSboxExt0(x) (iSsm0[x])
182 #define iSboxExt1(x) (rotr(iSsm0[x], 8))
183 #define iSboxExt2(x) (rotr(iSsm0[x], 16))
184 #define iSboxExt3(x) (rotr(iSsm0[x], 24))
185
186 /* see bearssl.h */
187 void
br_aes_big_decrypt(unsigned num_rounds,const uint32_t * skey,void * data)188 br_aes_big_decrypt(unsigned num_rounds, const uint32_t *skey, void *data)
189 {
190 unsigned char *buf;
191 uint32_t s0, s1, s2, s3;
192 uint32_t t0, t1, t2, t3;
193 unsigned u;
194
195 buf = data;
196 s0 = br_dec32be(buf);
197 s1 = br_dec32be(buf + 4);
198 s2 = br_dec32be(buf + 8);
199 s3 = br_dec32be(buf + 12);
200 s0 ^= skey[(num_rounds << 2) + 0];
201 s1 ^= skey[(num_rounds << 2) + 1];
202 s2 ^= skey[(num_rounds << 2) + 2];
203 s3 ^= skey[(num_rounds << 2) + 3];
204 for (u = num_rounds - 1; u > 0; u --) {
205 uint32_t v0 = iSboxExt0(s0 >> 24)
206 ^ iSboxExt1((s3 >> 16) & 0xFF)
207 ^ iSboxExt2((s2 >> 8) & 0xFF)
208 ^ iSboxExt3(s1 & 0xFF);
209 uint32_t v1 = iSboxExt0(s1 >> 24)
210 ^ iSboxExt1((s0 >> 16) & 0xFF)
211 ^ iSboxExt2((s3 >> 8) & 0xFF)
212 ^ iSboxExt3(s2 & 0xFF);
213 uint32_t v2 = iSboxExt0(s2 >> 24)
214 ^ iSboxExt1((s1 >> 16) & 0xFF)
215 ^ iSboxExt2((s0 >> 8) & 0xFF)
216 ^ iSboxExt3(s3 & 0xFF);
217 uint32_t v3 = iSboxExt0(s3 >> 24)
218 ^ iSboxExt1((s2 >> 16) & 0xFF)
219 ^ iSboxExt2((s1 >> 8) & 0xFF)
220 ^ iSboxExt3(s0 & 0xFF);
221 s0 = v0;
222 s1 = v1;
223 s2 = v2;
224 s3 = v3;
225 s0 ^= skey[u << 2];
226 s1 ^= skey[(u << 2) + 1];
227 s2 ^= skey[(u << 2) + 2];
228 s3 ^= skey[(u << 2) + 3];
229 }
230 t0 = ((uint32_t)iS[s0 >> 24] << 24)
231 | ((uint32_t)iS[(s3 >> 16) & 0xFF] << 16)
232 | ((uint32_t)iS[(s2 >> 8) & 0xFF] << 8)
233 | (uint32_t)iS[s1 & 0xFF];
234 t1 = ((uint32_t)iS[s1 >> 24] << 24)
235 | ((uint32_t)iS[(s0 >> 16) & 0xFF] << 16)
236 | ((uint32_t)iS[(s3 >> 8) & 0xFF] << 8)
237 | (uint32_t)iS[s2 & 0xFF];
238 t2 = ((uint32_t)iS[s2 >> 24] << 24)
239 | ((uint32_t)iS[(s1 >> 16) & 0xFF] << 16)
240 | ((uint32_t)iS[(s0 >> 8) & 0xFF] << 8)
241 | (uint32_t)iS[s3 & 0xFF];
242 t3 = ((uint32_t)iS[s3 >> 24] << 24)
243 | ((uint32_t)iS[(s2 >> 16) & 0xFF] << 16)
244 | ((uint32_t)iS[(s1 >> 8) & 0xFF] << 8)
245 | (uint32_t)iS[s0 & 0xFF];
246 s0 = t0 ^ skey[0];
247 s1 = t1 ^ skey[1];
248 s2 = t2 ^ skey[2];
249 s3 = t3 ^ skey[3];
250 br_enc32be(buf, s0);
251 br_enc32be(buf + 4, s1);
252 br_enc32be(buf + 8, s2);
253 br_enc32be(buf + 12, s3);
254 }
255