-
Notifications
You must be signed in to change notification settings - Fork 62
/
aes_keyschedule.c
280 lines (255 loc) · 12.1 KB
/
aes_keyschedule.c
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
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
/* ===================================================================== */
/* This file is a little helper to compute AES key scheduling */
/* from any round key */
/* Original author: Philippe Teuwen <[email protected]> 2016 */
/* */
/* Usage: */
/* aes_keyschedule AES_key_in_hex */
/* aes_keyschedule Round_key_in_hex Round_key_number_between_0_and_10 */
/* */
/* Examples: */
/* aes_keyschedule 11223344556677881122334455667788 */
/* aes_keyschedule 23D7F7B876B180306793B37432F5C4FC 1 */
/* aes_keyschedule 43EDA420DD033E7627347DC2CC6E0B4E 9 */
/* aes_keyschedule EAC68B6B37C5B51D10F1C8DFDC9FC391 10 */
/* */
/* Based on the Tiny AES128 in C https://github.com/kokke/tiny-AES128-C */
/* and released under the same licensing terms: */
/* */
/* This is free and unencumbered software released into the public domain*/
/* */
/* Anyone is free to copy, modify, publish, use, compile, sell, or */
/* distribute this software, either in source code form or as a compiled */
/* binary, for any purpose, commercial or non-commercial, and by any */
/* means. */
/* */
/* In jurisdictions that recognize copyright laws, the author or authors */
/* of this software dedicate any and all copyright interest in the */
/* software to the public domain. We make this dedication for the benefit*/
/* of the public at large and to the detriment of our heirs and */
/* successors. We intend this dedication to be an overt act of */
/* relinquishment in perpetuity of all present and future rights to this */
/* software under copyright law. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR */
/* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, */
/* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR */
/* OTHER DEALINGS IN THE SOFTWARE. */
/* */
/* For more information, please refer to <http://unlicense.org/> */
/* ===================================================================== */
/*****************************************************************************/
/* Includes: */
/*****************************************************************************/
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/*****************************************************************************/
/* Defines: */
/*****************************************************************************/
// The number of columns comprising a state in AES. This is a constant in AES. Value=4
#define Nb 4
/*****************************************************************************/
/* Private variables: */
/*****************************************************************************/
// state - array holding the intermediate results during decryption.
// The array that stores the round keys.
static uint8_t RoundKey[240];
// The Key input to the AES Program
static uint8_t Key[32];
// The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
// The numbers below can be computed dynamically trading ROM for RAM -
// This can be useful in (embedded) bootloader applications, where ROM is often limited.
static const uint8_t sbox[256] = {
//0 1 2 3 4 5 6 7 8 9 A B C D E F
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
// The round constant word array, Rcon[i], contains the values given by
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
// Note that i starts at 1, not 0).
static const uint8_t Rcon[11] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
void KeyExpansion(uint8_t start, uint16_t AesSize)
{
uint32_t i, j, k;
uint8_t tempa[4]; // Used for the column/row operations
uint8_t Nk = AesSize / 32;
// Nr: The number of rounds in AES Cipher: 10, 12 or 14
uint8_t Nr = Nk+6;
start *=4;
// The first round key is the key itself.
for(i = start; i < (Nk+start); ++i)
{
RoundKey[(i * 4) + 0] = Key[((i-start) * 4) + 0];
RoundKey[(i * 4) + 1] = Key[((i-start) * 4) + 1];
RoundKey[(i * 4) + 2] = Key[((i-start) * 4) + 2];
RoundKey[(i * 4) + 3] = Key[((i-start) * 4) + 3];
}
// All other round keys are found from the previous round keys.
for(; (i < (Nb * (Nr + 1))); ++i)
{
for(j = 0; j < 4; ++j)
{
tempa[j]=RoundKey[(i-1) * 4 + j];
}
if (i % Nk == 0)
{
// This function rotates the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
// Function RotWord()
{
k = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = k;
}
// SubWord() is a function that takes a four-byte input word and
// applies the S-box to each of the four bytes to produce an output word.
// Function Subword()
{
tempa[0] = sbox[tempa[0]];
tempa[1] = sbox[tempa[1]];
tempa[2] = sbox[tempa[2]];
tempa[3] = sbox[tempa[3]];
}
tempa[0] = tempa[0] ^ Rcon[i/Nk];
}
else if (Nk > 6 && i % Nk == 4)
{
// Function Subword()
{
tempa[0] = sbox[tempa[0]];
tempa[1] = sbox[tempa[1]];
tempa[2] = sbox[tempa[2]];
tempa[3] = sbox[tempa[3]];
}
}
RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0];
RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1];
RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
}
for(i=(Nk+start-1); i>(Nk-1); i--)
{
for(j = 0; j < 4; ++j)
{
tempa[j]=RoundKey[(i-1) * 4 + j];
}
if (i % Nk == 0)
{
// This function rotates the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
// Function RotWord()
{
k = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = k;
}
// SubWord() is a function that takes a four-byte input word and
// applies the S-box to each of the four bytes to produce an output word.
// Function Subword()
{
tempa[0] = sbox[tempa[0]];
tempa[1] = sbox[tempa[1]];
tempa[2] = sbox[tempa[2]];
tempa[3] = sbox[tempa[3]];
}
tempa[0] = tempa[0] ^ Rcon[i/Nk];
}
else if (Nk > 6 && i % Nk == 4)
{
// Function Subword()
{
tempa[0] = sbox[tempa[0]];
tempa[1] = sbox[tempa[1]];
tempa[2] = sbox[tempa[2]];
tempa[3] = sbox[tempa[3]];
}
}
RoundKey[(i - Nk) * 4 + 0] = RoundKey[i * 4 + 0] ^ tempa[0];
RoundKey[(i - Nk) * 4 + 1] = RoundKey[i * 4 + 1] ^ tempa[1];
RoundKey[(i - Nk) * 4 + 2] = RoundKey[i * 4 + 2] ^ tempa[2];
RoundKey[(i - Nk) * 4 + 3] = RoundKey[i * 4 + 3] ^ tempa[3];
}
for(j = 0; j < 16*(Nr+1); ++j)
{
if (j%16==0)
printf("K%02i: ", j/16);
printf("%02X", RoundKey[j]);
if (j%16==15)
printf("\n");
}
}
unsigned char is_hex_char(char c)
{
return (
(c >= '0' && c <= '9') ||
(c >= 'a' && c <= 'f') ||
(c >= 'A' && c <= 'F')
);
}
int main(int argc, char *argv[])
{
uint8_t i;
uint8_t round=0;
if (argc<2) {
printf("Usage: \n%s AES_key_in_hex\n", argv[0]);
printf("%s Round_key(s)_in_hex Initial_round_key_number_between_0_and_10#11#13\n", argv[0]);
printf("Examples:\n");
printf("- AES-128: (provide 1 round key)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A\n", argv[0]);
printf(" %s 97F926D5677B324AC439D77C8B03FDF8 5\n", argv[0]);
printf(" %s FAEF63792F9A97A1FB78C88C4CA7048F 10\n", argv[0]);
printf("- AES-192: (provide 1.5 round keys)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1\n", argv[0]);
printf(" %s D42AAFEB1510F368D8AA1354A707697696D6CC20F7737995 5\n", argv[0]);
printf(" %s 504B601C4EEB5C33B3D208B8E4966BA37B07118538961350 11\n", argv[0]);
printf(" Tip: check if the second half round key is the same as yours. If not => AES-256\n");
printf("- AES-256: (provide 2 round keys)\n");
printf(" %s B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1BB39F261BAC4729C\n", argv[0]);
printf(" %s F2E96B6FD53C1BBB49D0990E6FF86927DF8F909C21310695C43D2751C133AC12 5\n", argv[0]);
printf(" %s 4D69A4975189FCA00DB0AC8F686EE58C033BE6307A3C13C226DF38591EEAC857 13\n", argv[0]);
return EXIT_FAILURE;
}
uint32_t arglen = strlen(argv[1]);
if( (arglen != 32) && (arglen != 48) && (arglen != 64)) {
printf("Error: AES_key must be 16, 24 or 32-byte long\n");
return EXIT_FAILURE;
}
uint16_t AesSize = arglen * 4;
for(i = 0; i < arglen; i += 2)
{
if(is_hex_char(argv[1][i]) == 0 || is_hex_char(argv[1][i + 1]) == 0)
return EXIT_FAILURE;
unsigned char str_bytes[3] = {
argv[1][i],
argv[1][i + 1],
0
};
Key[ i / 2] = strtoul((const char*)str_bytes, NULL, 16);
}
if (argc > 2)
round = atoi(argv[2]);
KeyExpansion(round, AesSize);
}