4 * AES Cipher Algorithm.
6 * Based on Brian Gladman's code.
9 * Alexander Kjeldaas <astor@fast.no>
10 * Herbert Valerio Riedel <hvr@hvrlab.org>
11 * Kyle McMartin <kyle@debian.org>
12 * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API).
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * ---------------------------------------------------------------------------
20 * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
21 * All rights reserved.
25 * The free distribution and use of this software in both source and binary
26 * form is allowed (with or without changes) provided that:
28 * 1. distributions of this source code include the above copyright
29 * notice, this list of conditions and the following disclaimer;
31 * 2. distributions in binary form include the above copyright
32 * notice, this list of conditions and the following disclaimer
33 * in the documentation and/or other associated materials;
35 * 3. the copyright holder's name is not used to endorse products
36 * built using this software without specific written permission.
38 * ALTERNATIVELY, provided that this notice is retained in full, this product
39 * may be distributed under the terms of the GNU General Public License (GPL),
40 * in which case the provisions of the GPL apply INSTEAD OF those given above.
44 * This software is provided 'as is' with no explicit or implied warranties
45 * in respect of its properties, including, but not limited to, correctness
46 * and/or fitness for purpose.
47 * ---------------------------------------------------------------------------
50 /* Some changes from the Gladman version:
51 s/RIJNDAEL(e_key)/E_KEY/g
52 s/RIJNDAEL(d_key)/D_KEY/g
55 #include <crypto/aes.h>
56 #include <linux/module.h>
57 #include <linux/init.h>
58 #include <linux/types.h>
59 #include <linux/errno.h>
60 #include <linux/crypto.h>
61 #include <asm/byteorder.h>
64 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
66 static inline u8 byte(const u32 x, const unsigned n)
76 #define E_KEY (&ctx->buf[0])
77 #define D_KEY (&ctx->buf[60])
79 static u8 pow_tab[256] __initdata;
80 static u8 log_tab[256] __initdata;
81 static u8 sbx_tab[256] __initdata;
82 static u8 isb_tab[256] __initdata;
83 static u32 rco_tab[10];
84 static u32 ft_tab[4][256];
85 static u32 it_tab[4][256];
87 static u32 fl_tab[4][256];
88 static u32 il_tab[4][256];
90 static inline u8 __init f_mult(u8 a, u8 b)
92 u8 aa = log_tab[a], cc = aa + log_tab[b];
94 return pow_tab[cc + (cc < aa ? 1 : 0)];
97 #define ff_mult(a, b) (a && b ? f_mult(a, b) : 0)
99 static void __init gen_tabs(void)
105 * log and power tables for GF(2**8) finite field with
106 * 0x011b as modular polynomial - the simplest primitive
107 * root is 0x03, used here to generate the tables
110 for (i = 0, p = 1; i < 256; ++i) {
114 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
119 for (i = 0, p = 1; i < 10; ++i) {
122 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
125 for (i = 0; i < 256; ++i) {
126 p = (i ? pow_tab[255 - log_tab[i]] : 0);
127 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
128 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
133 for (i = 0; i < 256; ++i) {
138 fl_tab[1][i] = rol32(t, 8);
139 fl_tab[2][i] = rol32(t, 16);
140 fl_tab[3][i] = rol32(t, 24);
142 t = ((u32) ff_mult(2, p)) |
144 ((u32) p << 16) | ((u32) ff_mult(3, p) << 24);
147 ft_tab[1][i] = rol32(t, 8);
148 ft_tab[2][i] = rol32(t, 16);
149 ft_tab[3][i] = rol32(t, 24);
155 il_tab[1][i] = rol32(t, 8);
156 il_tab[2][i] = rol32(t, 16);
157 il_tab[3][i] = rol32(t, 24);
159 t = ((u32) ff_mult(14, p)) |
160 ((u32) ff_mult(9, p) << 8) |
161 ((u32) ff_mult(13, p) << 16) |
162 ((u32) ff_mult(11, p) << 24);
165 it_tab[1][i] = rol32(t, 8);
166 it_tab[2][i] = rol32(t, 16);
167 it_tab[3][i] = rol32(t, 24);
171 /* initialise the key schedule from the user supplied key */
173 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
175 #define imix_col(y,x) do { \
181 (y) ^= ror32(u ^ t, 8) ^ \
187 fl_tab[0][byte(x, 0)] ^ \
188 fl_tab[1][byte(x, 1)] ^ \
189 fl_tab[2][byte(x, 2)] ^ \
190 fl_tab[3][byte(x, 3)]
192 #define loop4(i) do { \
194 t = ls_box(t) ^ rco_tab[i]; \
196 E_KEY[4 * i + 4] = t; \
197 t ^= E_KEY[4 * i + 1]; \
198 E_KEY[4 * i + 5] = t; \
199 t ^= E_KEY[4 * i + 2]; \
200 E_KEY[4 * i + 6] = t; \
201 t ^= E_KEY[4 * i + 3]; \
202 E_KEY[4 * i + 7] = t; \
205 #define loop6(i) do { \
207 t = ls_box(t) ^ rco_tab[i]; \
209 E_KEY[6 * i + 6] = t; \
210 t ^= E_KEY[6 * i + 1]; \
211 E_KEY[6 * i + 7] = t; \
212 t ^= E_KEY[6 * i + 2]; \
213 E_KEY[6 * i + 8] = t; \
214 t ^= E_KEY[6 * i + 3]; \
215 E_KEY[6 * i + 9] = t; \
216 t ^= E_KEY[6 * i + 4]; \
217 E_KEY[6 * i + 10] = t; \
218 t ^= E_KEY[6 * i + 5]; \
219 E_KEY[6 * i + 11] = t; \
222 #define loop8(i) do { \
224 t = ls_box(t) ^ rco_tab[i]; \
226 E_KEY[8 * i + 8] = t; \
227 t ^= E_KEY[8 * i + 1]; \
228 E_KEY[8 * i + 9] = t; \
229 t ^= E_KEY[8 * i + 2]; \
230 E_KEY[8 * i + 10] = t; \
231 t ^= E_KEY[8 * i + 3]; \
232 E_KEY[8 * i + 11] = t; \
233 t = E_KEY[8 * i + 4] ^ ls_box(t); \
234 E_KEY[8 * i + 12] = t; \
235 t ^= E_KEY[8 * i + 5]; \
236 E_KEY[8 * i + 13] = t; \
237 t ^= E_KEY[8 * i + 6]; \
238 E_KEY[8 * i + 14] = t; \
239 t ^= E_KEY[8 * i + 7]; \
240 E_KEY[8 * i + 15] = t; \
243 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
244 unsigned int key_len)
246 struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
247 const __le32 *key = (const __le32 *)in_key;
248 u32 *flags = &tfm->crt_flags;
252 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
256 ctx->key_length = key_len;
258 E_KEY[0] = le32_to_cpu(key[0]);
259 E_KEY[1] = le32_to_cpu(key[1]);
260 E_KEY[2] = le32_to_cpu(key[2]);
261 E_KEY[3] = le32_to_cpu(key[3]);
266 for (i = 0; i < 10; ++i)
271 E_KEY[4] = le32_to_cpu(key[4]);
272 t = E_KEY[5] = le32_to_cpu(key[5]);
273 for (i = 0; i < 8; ++i)
278 E_KEY[4] = le32_to_cpu(key[4]);
279 E_KEY[5] = le32_to_cpu(key[5]);
280 E_KEY[6] = le32_to_cpu(key[6]);
281 t = E_KEY[7] = le32_to_cpu(key[7]);
282 for (i = 0; i < 7; ++i)
292 for (i = 4; i < key_len + 24; ++i) {
293 imix_col(D_KEY[i], E_KEY[i]);
299 /* encrypt a block of text */
301 #define f_rn(bo, bi, n, k) do { \
302 bo[n] = ft_tab[0][byte(bi[n], 0)] ^ \
303 ft_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \
304 ft_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
305 ft_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \
308 #define f_nround(bo, bi, k) do {\
309 f_rn(bo, bi, 0, k); \
310 f_rn(bo, bi, 1, k); \
311 f_rn(bo, bi, 2, k); \
312 f_rn(bo, bi, 3, k); \
316 #define f_rl(bo, bi, n, k) do { \
317 bo[n] = fl_tab[0][byte(bi[n], 0)] ^ \
318 fl_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \
319 fl_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
320 fl_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \
323 #define f_lround(bo, bi, k) do {\
324 f_rl(bo, bi, 0, k); \
325 f_rl(bo, bi, 1, k); \
326 f_rl(bo, bi, 2, k); \
327 f_rl(bo, bi, 3, k); \
330 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
332 const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
333 const __le32 *src = (const __le32 *)in;
334 __le32 *dst = (__le32 *)out;
336 const u32 *kp = E_KEY + 4;
338 b0[0] = le32_to_cpu(src[0]) ^ E_KEY[0];
339 b0[1] = le32_to_cpu(src[1]) ^ E_KEY[1];
340 b0[2] = le32_to_cpu(src[2]) ^ E_KEY[2];
341 b0[3] = le32_to_cpu(src[3]) ^ E_KEY[3];
343 if (ctx->key_length > 24) {
344 f_nround(b1, b0, kp);
345 f_nround(b0, b1, kp);
348 if (ctx->key_length > 16) {
349 f_nround(b1, b0, kp);
350 f_nround(b0, b1, kp);
353 f_nround(b1, b0, kp);
354 f_nround(b0, b1, kp);
355 f_nround(b1, b0, kp);
356 f_nround(b0, b1, kp);
357 f_nround(b1, b0, kp);
358 f_nround(b0, b1, kp);
359 f_nround(b1, b0, kp);
360 f_nround(b0, b1, kp);
361 f_nround(b1, b0, kp);
362 f_lround(b0, b1, kp);
364 dst[0] = cpu_to_le32(b0[0]);
365 dst[1] = cpu_to_le32(b0[1]);
366 dst[2] = cpu_to_le32(b0[2]);
367 dst[3] = cpu_to_le32(b0[3]);
370 /* decrypt a block of text */
372 #define i_rn(bo, bi, n, k) do { \
373 bo[n] = it_tab[0][byte(bi[n], 0)] ^ \
374 it_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \
375 it_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
376 it_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \
379 #define i_nround(bo, bi, k) do {\
380 i_rn(bo, bi, 0, k); \
381 i_rn(bo, bi, 1, k); \
382 i_rn(bo, bi, 2, k); \
383 i_rn(bo, bi, 3, k); \
387 #define i_rl(bo, bi, n, k) do { \
388 bo[n] = il_tab[0][byte(bi[n], 0)] ^ \
389 il_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \
390 il_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \
391 il_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \
394 #define i_lround(bo, bi, k) do {\
395 i_rl(bo, bi, 0, k); \
396 i_rl(bo, bi, 1, k); \
397 i_rl(bo, bi, 2, k); \
398 i_rl(bo, bi, 3, k); \
401 static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
403 const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
404 const __le32 *src = (const __le32 *)in;
405 __le32 *dst = (__le32 *)out;
407 const int key_len = ctx->key_length;
408 const u32 *kp = D_KEY + key_len + 20;
410 b0[0] = le32_to_cpu(src[0]) ^ E_KEY[key_len + 24];
411 b0[1] = le32_to_cpu(src[1]) ^ E_KEY[key_len + 25];
412 b0[2] = le32_to_cpu(src[2]) ^ E_KEY[key_len + 26];
413 b0[3] = le32_to_cpu(src[3]) ^ E_KEY[key_len + 27];
416 i_nround(b1, b0, kp);
417 i_nround(b0, b1, kp);
421 i_nround(b1, b0, kp);
422 i_nround(b0, b1, kp);
425 i_nround(b1, b0, kp);
426 i_nround(b0, b1, kp);
427 i_nround(b1, b0, kp);
428 i_nround(b0, b1, kp);
429 i_nround(b1, b0, kp);
430 i_nround(b0, b1, kp);
431 i_nround(b1, b0, kp);
432 i_nround(b0, b1, kp);
433 i_nround(b1, b0, kp);
434 i_lround(b0, b1, kp);
436 dst[0] = cpu_to_le32(b0[0]);
437 dst[1] = cpu_to_le32(b0[1]);
438 dst[2] = cpu_to_le32(b0[2]);
439 dst[3] = cpu_to_le32(b0[3]);
442 static struct crypto_alg aes_alg = {
444 .cra_driver_name = "aes-generic",
446 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
447 .cra_blocksize = AES_BLOCK_SIZE,
448 .cra_ctxsize = sizeof(struct aes_ctx),
450 .cra_module = THIS_MODULE,
451 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
454 .cia_min_keysize = AES_MIN_KEY_SIZE,
455 .cia_max_keysize = AES_MAX_KEY_SIZE,
456 .cia_setkey = aes_set_key,
457 .cia_encrypt = aes_encrypt,
458 .cia_decrypt = aes_decrypt
463 static int __init aes_init(void)
466 return crypto_register_alg(&aes_alg);
469 static void __exit aes_fini(void)
471 crypto_unregister_alg(&aes_alg);
474 module_init(aes_init);
475 module_exit(aes_fini);
477 MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
478 MODULE_LICENSE("Dual BSD/GPL");