source: mainline/uspace/lib/crypto/aes.c@ a931b7b

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since a931b7b was d7dadcb4, checked in by Jan Kolarik <kolarik@…>, 11 years ago

RC4 and MD5 algorithm used in TKIP/WEP security suites
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1/*
2 * Copyright (c) 2015 Jan Kolarik
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @file aes.c
30 *
31 * Implementation of AES-128 symmetric cipher cryptographic algorithm.
32 *
33 * Based on FIPS 197.
34 */
35
36#include <stdbool.h>
37#include <errno.h>
38#include <mem.h>
39
40#include "crypto.h"
41
42/* Number of elements in rows/columns in AES arrays. */
43#define ELEMS 4
44
45/* Number of elements (words) in cipher. */
46#define CIPHER_ELEMS 4
47
48/* Length of AES block. */
49#define BLOCK_LEN 16
50
51/* Number of iterations in AES algorithm. */
52#define ROUNDS 10
53
54/*
55 * Irreducible polynomial used in AES algorithm.
56 *
57 * NOTE: x^8 + x^4 + x^3 + x + 1.
58 */
59#define AES_IP 0x1B
60
61/* Precomputed values for AES sub_byte transformation. */
62static const uint8_t sbox[BLOCK_LEN][BLOCK_LEN] = {
63 {
64 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
65 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76
66 },
67 {
68 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
69 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0
70 },
71 {
72 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
73 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15
74 },
75 {
76 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
77 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75
78 },
79 {
80 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
81 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84
82 },
83 {
84 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
85 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf
86 },
87 {
88 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
89 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8
90 },
91 {
92 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
93 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2
94 },
95 {
96 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
97 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73
98 },
99 {
100 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
101 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb
102 },
103 {
104 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
105 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79
106 },
107 {
108 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
109 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08
110 },
111 {
112 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
113 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a
114 },
115 {
116 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
117 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e
118 },
119 {
120 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
121 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf
122 },
123 {
124 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
125 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
126 }
127};
128
129/* Precomputed values for AES inv_sub_byte transformation. */
130static uint8_t inv_sbox[BLOCK_LEN][BLOCK_LEN] = {
131 {
132 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
133 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb
134 },
135 {
136 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
137 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb
138 },
139 {
140 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
141 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e
142 },
143 {
144 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
145 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25
146 },
147 {
148 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
149 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92
150 },
151 {
152 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
153 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84
154 },
155 {
156 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
157 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06
158 },
159 {
160 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
161 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b
162 },
163 {
164 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
165 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73
166 },
167 {
168 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
169 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e
170 },
171 {
172 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
173 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b
174 },
175 {
176 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
177 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4
178 },
179 {
180 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
181 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f
182 },
183 {
184 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
185 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef
186 },
187 {
188 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
189 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61
190 },
191 {
192 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
193 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
194 }
195};
196
197/* Precomputed values of powers of 2 in GF(2^8) left shifted by 24b. */
198static const uint32_t r_con_array[] = {
199 0x01000000, 0x02000000, 0x04000000, 0x08000000,
200 0x10000000, 0x20000000, 0x40000000, 0x80000000,
201 0x1B000000, 0x36000000
202};
203
204/**
205 * Perform substitution transformation on given byte.
206 *
207 * @param byte Input byte.
208 * @param inv Flag indicating whether to use inverse table.
209 *
210 * @return Substituted value.
211 */
212static uint8_t sub_byte(uint8_t byte, bool inv)
213{
214 uint8_t i = byte >> 4;
215 uint8_t j = byte & 0xF;
216
217 if(!inv) {
218 return sbox[i][j];
219 } else {
220 return inv_sbox[i][j];
221 }
222}
223
224/**
225 * Perform substitution transformation on state table.
226 *
227 * @param state State table to be modified.
228 * @param inv Flag indicating whether to use inverse table.
229 */
230static void sub_bytes(uint8_t state[ELEMS][ELEMS], bool inv)
231{
232 uint8_t val;
233
234 for(size_t i = 0; i < ELEMS; i++) {
235 for(size_t j = 0; j < ELEMS; j++) {
236 val = state[i][j];
237 state[i][j] = sub_byte(val, inv);
238 }
239 }
240}
241
242/**
243 * Perform shift rows transformation on state table.
244 *
245 * @param state State table to be modified.
246 */
247static void shift_rows(uint8_t state[ELEMS][ELEMS])
248{
249 uint8_t temp[ELEMS];
250
251 for(size_t i = 1; i < ELEMS; i++) {
252 memcpy(temp, state[i], i);
253 memcpy(state[i], state[i] + i, ELEMS - i);
254 memcpy(state[i] + ELEMS - i, temp, i);
255 }
256}
257
258/**
259 * Perform inverted shift rows transformation on state table.
260 *
261 * @param state State table to be modified.
262 */
263static void inv_shift_rows(uint8_t state[ELEMS][ELEMS])
264{
265 uint8_t temp[ELEMS];
266
267 for(size_t i = 1; i < ELEMS; i++) {
268 memcpy(temp, state[i], ELEMS - i);
269 memcpy(state[i], state[i] + ELEMS - i, i);
270 memcpy(state[i] + i, temp, ELEMS - i);
271 }
272}
273
274/**
275 * Multiplication in GF(2^8).
276 *
277 * @param x First factor.
278 * @param y Second factor.
279 *
280 * @return Multiplication of given factors in GF(2^8).
281 */
282static uint8_t galois_mult(uint8_t x, uint8_t y) {
283 uint8_t result = 0;
284 uint8_t F_bitH;
285
286 for(size_t i = 0; i < 8; i++) {
287 if (y & 1)
288 result ^= x;
289 F_bitH = (x & 0x80);
290 x <<= 1;
291 if (F_bitH)
292 x ^= AES_IP;
293 y >>= 1;
294 }
295
296 return result;
297}
298
299/**
300 * Perform mix columns transformation on state table.
301 *
302 * @param state State table to be modified.
303 */
304static void mix_columns(uint8_t state[ELEMS][ELEMS])
305{
306 uint8_t orig_state[ELEMS][ELEMS];
307 memcpy(orig_state, state, BLOCK_LEN);
308
309 for(size_t j = 0; j < ELEMS; j++) {
310 state[0][j] =
311 galois_mult(0x2, orig_state[0][j]) ^
312 galois_mult(0x3, orig_state[1][j]) ^
313 orig_state[2][j] ^
314 orig_state[3][j];
315 state[1][j] =
316 orig_state[0][j] ^
317 galois_mult(0x2, orig_state[1][j]) ^
318 galois_mult(0x3, orig_state[2][j]) ^
319 orig_state[3][j];
320 state[2][j] =
321 orig_state[0][j] ^
322 orig_state[1][j] ^
323 galois_mult(0x2, orig_state[2][j]) ^
324 galois_mult(0x3, orig_state[3][j]);
325 state[3][j] =
326 galois_mult(0x3, orig_state[0][j]) ^
327 orig_state[1][j] ^
328 orig_state[2][j] ^
329 galois_mult(0x2, orig_state[3][j]);
330 }
331}
332
333/**
334 * Perform inverted mix columns transformation on state table.
335 *
336 * @param state State table to be modified.
337 */
338static void inv_mix_columns(uint8_t state[ELEMS][ELEMS])
339{
340 uint8_t orig_state[ELEMS][ELEMS];
341 memcpy(orig_state, state, BLOCK_LEN);
342
343 for(size_t j = 0; j < ELEMS; j++) {
344 state[0][j] =
345 galois_mult(0x0E, orig_state[0][j]) ^
346 galois_mult(0x0B, orig_state[1][j]) ^
347 galois_mult(0x0D, orig_state[2][j]) ^
348 galois_mult(0x09, orig_state[3][j]);
349 state[1][j] =
350 galois_mult(0x09, orig_state[0][j]) ^
351 galois_mult(0x0E, orig_state[1][j]) ^
352 galois_mult(0x0B, orig_state[2][j]) ^
353 galois_mult(0x0D, orig_state[3][j]);
354 state[2][j] =
355 galois_mult(0x0D, orig_state[0][j]) ^
356 galois_mult(0x09, orig_state[1][j]) ^
357 galois_mult(0x0E, orig_state[2][j]) ^
358 galois_mult(0x0B, orig_state[3][j]);
359 state[3][j] =
360 galois_mult(0x0B, orig_state[0][j]) ^
361 galois_mult(0x0D, orig_state[1][j]) ^
362 galois_mult(0x09, orig_state[2][j]) ^
363 galois_mult(0x0E, orig_state[3][j]);
364 }
365}
366
367/**
368 * Perform round key transformation on state table.
369 *
370 * @param state State table to be modified.
371 * @param round_key Round key to be applied on state table.
372 */
373static void add_round_key(uint8_t state[ELEMS][ELEMS], uint32_t *round_key)
374{
375 uint8_t byte_round;
376 uint8_t shift;
377 uint32_t mask = 0xFF;
378
379 for(size_t j = 0; j < ELEMS; j++) {
380 for(size_t i = 0; i < ELEMS; i++) {
381 shift = 24 - 8*i;
382 byte_round = (round_key[j] & (mask << shift)) >> shift;
383 state[i][j] = state[i][j] ^ byte_round;
384 }
385 }
386}
387
388/**
389 * Perform substitution transformation on given word.
390 *
391 * @param byte Input word.
392 *
393 * @return Substituted word.
394 */
395static uint32_t sub_word(uint32_t word)
396{
397 uint32_t temp = word;
398 uint8_t *start = (uint8_t *) &temp;
399
400 for(size_t i = 0; i < 4; i++) {
401 *(start+i) = sub_byte(*(start+i), false);
402 }
403
404 return temp;
405}
406
407/**
408 * Perform left rotation by one byte on given word.
409 *
410 * @param byte Input word.
411 *
412 * @return Rotated word.
413 */
414static uint32_t rot_word(uint32_t word)
415{
416 return (word << 8 | word >> 24);
417}
418
419/**
420 * Key expansion procedure for AES algorithm.
421 *
422 * @param key Input key.
423 * @param key_exp Result key expansion.
424 */
425static void key_expansion(uint8_t *key, uint32_t *key_exp)
426{
427 uint32_t temp;
428
429 for(size_t i = 0; i < CIPHER_ELEMS; i++) {
430 key_exp[i] =
431 (key[4*i] << 24) +
432 (key[4*i+1] << 16) +
433 (key[4*i+2] << 8) +
434 (key[4*i+3]);
435 }
436
437 for(size_t i = CIPHER_ELEMS; i < ELEMS * (ROUNDS + 1); i++) {
438 temp = key_exp[i-1];
439
440 if((i % CIPHER_ELEMS) == 0) {
441 temp = sub_word(rot_word(temp)) ^
442 r_con_array[i/CIPHER_ELEMS - 1];
443 }
444
445 key_exp[i] = key_exp[i - CIPHER_ELEMS] ^ temp;
446 }
447}
448
449/**
450 * AES-128 encryption algorithm.
451 *
452 * @param key Input key.
453 * @param input Input data sequence to be encrypted.
454 * @param output Encrypted data sequence.
455 *
456 * @return EINVAL when input or key not specified, ENOMEM when pointer for
457 * output is not allocated, otherwise EOK.
458 */
459int aes_encrypt(uint8_t *key, uint8_t *input, uint8_t *output)
460{
461 if(!key || !input)
462 return EINVAL;
463
464 if(!output)
465 return ENOMEM;
466
467 /* Create key expansion. */
468 uint32_t key_exp[ELEMS * (ROUNDS+1)];
469 key_expansion(key, key_exp);
470
471 /* Copy input into state array. */
472 uint8_t state[ELEMS][ELEMS];
473 for(size_t i = 0; i < ELEMS; i++) {
474 for(size_t j = 0; j < ELEMS; j++) {
475 state[i][j] = input[i + ELEMS*j];
476 }
477 }
478
479 /* Processing loop. */
480 add_round_key(state, key_exp);
481
482 for(size_t k = 1; k <= ROUNDS; k++) {
483 sub_bytes(state, false);
484 shift_rows(state);
485 if(k < ROUNDS)
486 mix_columns(state);
487 add_round_key(state, key_exp + k*ELEMS);
488 }
489
490 /* Copy state array into output. */
491 for(size_t i = 0; i < ELEMS; i++) {
492 for(size_t j = 0; j < ELEMS; j++) {
493 output[i + j*ELEMS] = state[i][j];
494 }
495 }
496
497 return EOK;
498}
499
500/**
501 * AES-128 decryption algorithm.
502 *
503 * @param key Input key.
504 * @param input Input data sequence to be decrypted.
505 * @param output Decrypted data sequence.
506 *
507 * @return EINVAL when input or key not specified, ENOMEM when pointer for
508 * output is not allocated, otherwise EOK.
509 */
510int aes_decrypt(uint8_t *key, uint8_t *input, uint8_t *output)
511{
512 if(!key || !input)
513 return EINVAL;
514
515 if(!output)
516 return ENOMEM;
517
518 /* Create key expansion. */
519 uint32_t key_exp[ELEMS * (ROUNDS+1)];
520 key_expansion(key, key_exp);
521
522 /* Copy input into state array. */
523 uint8_t state[ELEMS][ELEMS];
524 for(size_t i = 0; i < ELEMS; i++) {
525 for(size_t j = 0; j < ELEMS; j++) {
526 state[i][j] = input[i + ELEMS*j];
527 }
528 }
529
530 /* Processing loop. */
531 add_round_key(state, key_exp + ROUNDS*ELEMS);
532
533 for(int k = ROUNDS - 1; k >= 0; k--) {
534 inv_shift_rows(state);
535 sub_bytes(state, true);
536 add_round_key(state, key_exp + k*ELEMS);
537 if(k > 0)
538 inv_mix_columns(state);
539 }
540
541 /* Copy state array into output. */
542 for(size_t i = 0; i < ELEMS; i++) {
543 for(size_t j = 0; j < ELEMS; j++) {
544 output[i + j*ELEMS] = state[i][j];
545 }
546 }
547
548 return EOK;
549}
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