Annotation of embedaddon/axTLS/crypto/aes.c, revision 1.1.1.1
1.1 misho 1: /*
2: * Copyright (c) 2007, Cameron Rich
3: *
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 met:
8: *
9: * * Redistributions of source code must retain the above copyright notice,
10: * this list of conditions and the following disclaimer.
11: * * Redistributions in binary form must reproduce the above copyright notice,
12: * this list of conditions and the following disclaimer in the documentation
13: * and/or other materials provided with the distribution.
14: * * Neither the name of the axTLS project nor the names of its contributors
15: * may be used to endorse or promote products derived from this software
16: * without specific prior written permission.
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 OWNER OR
22: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27: * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29: */
30:
31: /**
32: * AES implementation - this is a small code version. There are much faster
33: * versions around but they are much larger in size (i.e. they use large
34: * submix tables).
35: */
36:
37: #include <string.h>
38: #include "os_port.h"
39: #include "crypto.h"
40:
41: /* all commented out in skeleton mode */
42: #ifndef CONFIG_SSL_SKELETON_MODE
43:
44: #define rot1(x) (((x) << 24) | ((x) >> 8))
45: #define rot2(x) (((x) << 16) | ((x) >> 16))
46: #define rot3(x) (((x) << 8) | ((x) >> 24))
47:
48: /*
49: * This cute trick does 4 'mul by two' at once. Stolen from
50: * Dr B. R. Gladman <brg@gladman.uk.net> but I'm sure the u-(u>>7) is
51: * a standard graphics trick
52: * The key to this is that we need to xor with 0x1b if the top bit is set.
53: * a 1xxx xxxx 0xxx 0xxx First we mask the 7bit,
54: * b 1000 0000 0000 0000 then we shift right by 7 putting the 7bit in 0bit,
55: * c 0000 0001 0000 0000 we then subtract (c) from (b)
56: * d 0111 1111 0000 0000 and now we and with our mask
57: * e 0001 1011 0000 0000
58: */
59: #define mt 0x80808080
60: #define ml 0x7f7f7f7f
61: #define mh 0xfefefefe
62: #define mm 0x1b1b1b1b
63: #define mul2(x,t) ((t)=((x)&mt), \
64: ((((x)+(x))&mh)^(((t)-((t)>>7))&mm)))
65:
66: #define inv_mix_col(x,f2,f4,f8,f9) (\
67: (f2)=mul2(x,f2), \
68: (f4)=mul2(f2,f4), \
69: (f8)=mul2(f4,f8), \
70: (f9)=(x)^(f8), \
71: (f8)=((f2)^(f4)^(f8)), \
72: (f2)^=(f9), \
73: (f4)^=(f9), \
74: (f8)^=rot3(f2), \
75: (f8)^=rot2(f4), \
76: (f8)^rot1(f9))
77:
78: /*
79: * AES S-box
80: */
81: static const uint8_t aes_sbox[256] =
82: {
83: 0x63,0x7C,0x77,0x7B,0xF2,0x6B,0x6F,0xC5,
84: 0x30,0x01,0x67,0x2B,0xFE,0xD7,0xAB,0x76,
85: 0xCA,0x82,0xC9,0x7D,0xFA,0x59,0x47,0xF0,
86: 0xAD,0xD4,0xA2,0xAF,0x9C,0xA4,0x72,0xC0,
87: 0xB7,0xFD,0x93,0x26,0x36,0x3F,0xF7,0xCC,
88: 0x34,0xA5,0xE5,0xF1,0x71,0xD8,0x31,0x15,
89: 0x04,0xC7,0x23,0xC3,0x18,0x96,0x05,0x9A,
90: 0x07,0x12,0x80,0xE2,0xEB,0x27,0xB2,0x75,
91: 0x09,0x83,0x2C,0x1A,0x1B,0x6E,0x5A,0xA0,
92: 0x52,0x3B,0xD6,0xB3,0x29,0xE3,0x2F,0x84,
93: 0x53,0xD1,0x00,0xED,0x20,0xFC,0xB1,0x5B,
94: 0x6A,0xCB,0xBE,0x39,0x4A,0x4C,0x58,0xCF,
95: 0xD0,0xEF,0xAA,0xFB,0x43,0x4D,0x33,0x85,
96: 0x45,0xF9,0x02,0x7F,0x50,0x3C,0x9F,0xA8,
97: 0x51,0xA3,0x40,0x8F,0x92,0x9D,0x38,0xF5,
98: 0xBC,0xB6,0xDA,0x21,0x10,0xFF,0xF3,0xD2,
99: 0xCD,0x0C,0x13,0xEC,0x5F,0x97,0x44,0x17,
100: 0xC4,0xA7,0x7E,0x3D,0x64,0x5D,0x19,0x73,
101: 0x60,0x81,0x4F,0xDC,0x22,0x2A,0x90,0x88,
102: 0x46,0xEE,0xB8,0x14,0xDE,0x5E,0x0B,0xDB,
103: 0xE0,0x32,0x3A,0x0A,0x49,0x06,0x24,0x5C,
104: 0xC2,0xD3,0xAC,0x62,0x91,0x95,0xE4,0x79,
105: 0xE7,0xC8,0x37,0x6D,0x8D,0xD5,0x4E,0xA9,
106: 0x6C,0x56,0xF4,0xEA,0x65,0x7A,0xAE,0x08,
107: 0xBA,0x78,0x25,0x2E,0x1C,0xA6,0xB4,0xC6,
108: 0xE8,0xDD,0x74,0x1F,0x4B,0xBD,0x8B,0x8A,
109: 0x70,0x3E,0xB5,0x66,0x48,0x03,0xF6,0x0E,
110: 0x61,0x35,0x57,0xB9,0x86,0xC1,0x1D,0x9E,
111: 0xE1,0xF8,0x98,0x11,0x69,0xD9,0x8E,0x94,
112: 0x9B,0x1E,0x87,0xE9,0xCE,0x55,0x28,0xDF,
113: 0x8C,0xA1,0x89,0x0D,0xBF,0xE6,0x42,0x68,
114: 0x41,0x99,0x2D,0x0F,0xB0,0x54,0xBB,0x16,
115: };
116:
117: /*
118: * AES is-box
119: */
120: static const uint8_t aes_isbox[256] =
121: {
122: 0x52,0x09,0x6a,0xd5,0x30,0x36,0xa5,0x38,
123: 0xbf,0x40,0xa3,0x9e,0x81,0xf3,0xd7,0xfb,
124: 0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87,
125: 0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb,
126: 0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d,
127: 0xee,0x4c,0x95,0x0b,0x42,0xfa,0xc3,0x4e,
128: 0x08,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2,
129: 0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25,
130: 0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16,
131: 0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92,
132: 0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda,
133: 0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84,
134: 0x90,0xd8,0xab,0x00,0x8c,0xbc,0xd3,0x0a,
135: 0xf7,0xe4,0x58,0x05,0xb8,0xb3,0x45,0x06,
136: 0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0x0f,0x02,
137: 0xc1,0xaf,0xbd,0x03,0x01,0x13,0x8a,0x6b,
138: 0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea,
139: 0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73,
140: 0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85,
141: 0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e,
142: 0x47,0xf1,0x1a,0x71,0x1d,0x29,0xc5,0x89,
143: 0x6f,0xb7,0x62,0x0e,0xaa,0x18,0xbe,0x1b,
144: 0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20,
145: 0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4,
146: 0x1f,0xdd,0xa8,0x33,0x88,0x07,0xc7,0x31,
147: 0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f,
148: 0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0x0d,
149: 0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef,
150: 0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0,
151: 0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61,
152: 0x17,0x2b,0x04,0x7e,0xba,0x77,0xd6,0x26,
153: 0xe1,0x69,0x14,0x63,0x55,0x21,0x0c,0x7d
154: };
155:
156: static const unsigned char Rcon[30]=
157: {
158: 0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,
159: 0x1b,0x36,0x6c,0xd8,0xab,0x4d,0x9a,0x2f,
160: 0x5e,0xbc,0x63,0xc6,0x97,0x35,0x6a,0xd4,
161: 0xb3,0x7d,0xfa,0xef,0xc5,0x91,
162: };
163:
164: /* ----- static functions ----- */
165: static void AES_encrypt(const AES_CTX *ctx, uint32_t *data);
166: static void AES_decrypt(const AES_CTX *ctx, uint32_t *data);
167:
168: /* Perform doubling in Galois Field GF(2^8) using the irreducible polynomial
169: x^8+x^4+x^3+x+1 */
170: static unsigned char AES_xtime(uint32_t x)
171: {
172: return (x&0x80) ? (x<<1)^0x1b : x<<1;
173: }
174:
175: /**
176: * Set up AES with the key/iv and cipher size.
177: */
178: void AES_set_key(AES_CTX *ctx, const uint8_t *key,
179: const uint8_t *iv, AES_MODE mode)
180: {
181: int i, ii;
182: uint32_t *W, tmp, tmp2;
183: const unsigned char *ip;
184: int words;
185:
186: switch (mode)
187: {
188: case AES_MODE_128:
189: i = 10;
190: words = 4;
191: break;
192:
193: case AES_MODE_256:
194: i = 14;
195: words = 8;
196: break;
197:
198: default: /* fail silently */
199: return;
200: }
201:
202: ctx->rounds = i;
203: ctx->key_size = words;
204: W = ctx->ks;
205: for (i = 0; i < words; i+=2)
206: {
207: W[i+0]= ((uint32_t)key[ 0]<<24)|
208: ((uint32_t)key[ 1]<<16)|
209: ((uint32_t)key[ 2]<< 8)|
210: ((uint32_t)key[ 3] );
211: W[i+1]= ((uint32_t)key[ 4]<<24)|
212: ((uint32_t)key[ 5]<<16)|
213: ((uint32_t)key[ 6]<< 8)|
214: ((uint32_t)key[ 7] );
215: key += 8;
216: }
217:
218: ip = Rcon;
219: ii = 4 * (ctx->rounds+1);
220: for (i = words; i<ii; i++)
221: {
222: tmp = W[i-1];
223:
224: if ((i % words) == 0)
225: {
226: tmp2 =(uint32_t)aes_sbox[(tmp )&0xff]<< 8;
227: tmp2|=(uint32_t)aes_sbox[(tmp>> 8)&0xff]<<16;
228: tmp2|=(uint32_t)aes_sbox[(tmp>>16)&0xff]<<24;
229: tmp2|=(uint32_t)aes_sbox[(tmp>>24) ];
230: tmp=tmp2^(((unsigned int)*ip)<<24);
231: ip++;
232: }
233:
234: if ((words == 8) && ((i % words) == 4))
235: {
236: tmp2 =(uint32_t)aes_sbox[(tmp )&0xff] ;
237: tmp2|=(uint32_t)aes_sbox[(tmp>> 8)&0xff]<< 8;
238: tmp2|=(uint32_t)aes_sbox[(tmp>>16)&0xff]<<16;
239: tmp2|=(uint32_t)aes_sbox[(tmp>>24) ]<<24;
240: tmp=tmp2;
241: }
242:
243: W[i]=W[i-words]^tmp;
244: }
245:
246: /* copy the iv across */
247: memcpy(ctx->iv, iv, 16);
248: }
249:
250: /**
251: * Change a key for decryption.
252: */
253: void AES_convert_key(AES_CTX *ctx)
254: {
255: int i;
256: uint32_t *k,w,t1,t2,t3,t4;
257:
258: k = ctx->ks;
259: k += 4;
260:
261: for (i= ctx->rounds*4; i > 4; i--)
262: {
263: w= *k;
264: w = inv_mix_col(w,t1,t2,t3,t4);
265: *k++ =w;
266: }
267: }
268:
269: /**
270: * Encrypt a byte sequence (with a block size 16) using the AES cipher.
271: */
272: void AES_cbc_encrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length)
273: {
274: int i;
275: uint32_t tin[4], tout[4], iv[4];
276:
277: memcpy(iv, ctx->iv, AES_IV_SIZE);
278: for (i = 0; i < 4; i++)
279: tout[i] = ntohl(iv[i]);
280:
281: for (length -= AES_BLOCKSIZE; length >= 0; length -= AES_BLOCKSIZE)
282: {
283: uint32_t msg_32[4];
284: uint32_t out_32[4];
285: memcpy(msg_32, msg, AES_BLOCKSIZE);
286: msg += AES_BLOCKSIZE;
287:
288: for (i = 0; i < 4; i++)
289: tin[i] = ntohl(msg_32[i])^tout[i];
290:
291: AES_encrypt(ctx, tin);
292:
293: for (i = 0; i < 4; i++)
294: {
295: tout[i] = tin[i];
296: out_32[i] = htonl(tout[i]);
297: }
298:
299: memcpy(out, out_32, AES_BLOCKSIZE);
300: out += AES_BLOCKSIZE;
301: }
302:
303: for (i = 0; i < 4; i++)
304: iv[i] = htonl(tout[i]);
305: memcpy(ctx->iv, iv, AES_IV_SIZE);
306: }
307:
308: /**
309: * Decrypt a byte sequence (with a block size 16) using the AES cipher.
310: */
311: void AES_cbc_decrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length)
312: {
313: int i;
314: uint32_t tin[4], xor[4], tout[4], data[4], iv[4];
315:
316: memcpy(iv, ctx->iv, AES_IV_SIZE);
317: for (i = 0; i < 4; i++)
318: xor[i] = ntohl(iv[i]);
319:
320: for (length -= 16; length >= 0; length -= 16)
321: {
322: uint32_t msg_32[4];
323: uint32_t out_32[4];
324: memcpy(msg_32, msg, AES_BLOCKSIZE);
325: msg += AES_BLOCKSIZE;
326:
327: for (i = 0; i < 4; i++)
328: {
329: tin[i] = ntohl(msg_32[i]);
330: data[i] = tin[i];
331: }
332:
333: AES_decrypt(ctx, data);
334:
335: for (i = 0; i < 4; i++)
336: {
337: tout[i] = data[i]^xor[i];
338: xor[i] = tin[i];
339: out_32[i] = htonl(tout[i]);
340: }
341:
342: memcpy(out, out_32, AES_BLOCKSIZE);
343: out += AES_BLOCKSIZE;
344: }
345:
346: for (i = 0; i < 4; i++)
347: iv[i] = htonl(xor[i]);
348: memcpy(ctx->iv, iv, AES_IV_SIZE);
349: }
350:
351: /**
352: * Encrypt a single block (16 bytes) of data
353: */
354: static void AES_encrypt(const AES_CTX *ctx, uint32_t *data)
355: {
356: /* To make this code smaller, generate the sbox entries on the fly.
357: * This will have a really heavy effect upon performance.
358: */
359: uint32_t tmp[4];
360: uint32_t tmp1, old_a0, a0, a1, a2, a3, row;
361: int curr_rnd;
362: int rounds = ctx->rounds;
363: const uint32_t *k = ctx->ks;
364:
365: /* Pre-round key addition */
366: for (row = 0; row < 4; row++)
367: data[row] ^= *(k++);
368:
369: /* Encrypt one block. */
370: for (curr_rnd = 0; curr_rnd < rounds; curr_rnd++)
371: {
372: /* Perform ByteSub and ShiftRow operations together */
373: for (row = 0; row < 4; row++)
374: {
375: a0 = (uint32_t)aes_sbox[(data[row%4]>>24)&0xFF];
376: a1 = (uint32_t)aes_sbox[(data[(row+1)%4]>>16)&0xFF];
377: a2 = (uint32_t)aes_sbox[(data[(row+2)%4]>>8)&0xFF];
378: a3 = (uint32_t)aes_sbox[(data[(row+3)%4])&0xFF];
379:
380: /* Perform MixColumn iff not last round */
381: if (curr_rnd < (rounds - 1))
382: {
383: tmp1 = a0 ^ a1 ^ a2 ^ a3;
384: old_a0 = a0;
385: a0 ^= tmp1 ^ AES_xtime(a0 ^ a1);
386: a1 ^= tmp1 ^ AES_xtime(a1 ^ a2);
387: a2 ^= tmp1 ^ AES_xtime(a2 ^ a3);
388: a3 ^= tmp1 ^ AES_xtime(a3 ^ old_a0);
389: }
390:
391: tmp[row] = ((a0 << 24) | (a1 << 16) | (a2 << 8) | a3);
392: }
393:
394: /* KeyAddition - note that it is vital that this loop is separate from
395: the MixColumn operation, which must be atomic...*/
396: for (row = 0; row < 4; row++)
397: data[row] = tmp[row] ^ *(k++);
398: }
399: }
400:
401: /**
402: * Decrypt a single block (16 bytes) of data
403: */
404: static void AES_decrypt(const AES_CTX *ctx, uint32_t *data)
405: {
406: uint32_t tmp[4];
407: uint32_t xt0,xt1,xt2,xt3,xt4,xt5,xt6;
408: uint32_t a0, a1, a2, a3, row;
409: int curr_rnd;
410: int rounds = ctx->rounds;
411: const uint32_t *k = ctx->ks + ((rounds+1)*4);
412:
413: /* pre-round key addition */
414: for (row=4; row > 0;row--)
415: data[row-1] ^= *(--k);
416:
417: /* Decrypt one block */
418: for (curr_rnd = 0; curr_rnd < rounds; curr_rnd++)
419: {
420: /* Perform ByteSub and ShiftRow operations together */
421: for (row = 4; row > 0; row--)
422: {
423: a0 = aes_isbox[(data[(row+3)%4]>>24)&0xFF];
424: a1 = aes_isbox[(data[(row+2)%4]>>16)&0xFF];
425: a2 = aes_isbox[(data[(row+1)%4]>>8)&0xFF];
426: a3 = aes_isbox[(data[row%4])&0xFF];
427:
428: /* Perform MixColumn iff not last round */
429: if (curr_rnd<(rounds-1))
430: {
431: /* The MDS cofefficients (0x09, 0x0B, 0x0D, 0x0E)
432: are quite large compared to encryption; this
433: operation slows decryption down noticeably. */
434: xt0 = AES_xtime(a0^a1);
435: xt1 = AES_xtime(a1^a2);
436: xt2 = AES_xtime(a2^a3);
437: xt3 = AES_xtime(a3^a0);
438: xt4 = AES_xtime(xt0^xt1);
439: xt5 = AES_xtime(xt1^xt2);
440: xt6 = AES_xtime(xt4^xt5);
441:
442: xt0 ^= a1^a2^a3^xt4^xt6;
443: xt1 ^= a0^a2^a3^xt5^xt6;
444: xt2 ^= a0^a1^a3^xt4^xt6;
445: xt3 ^= a0^a1^a2^xt5^xt6;
446: tmp[row-1] = ((xt0<<24)|(xt1<<16)|(xt2<<8)|xt3);
447: }
448: else
449: tmp[row-1] = ((a0<<24)|(a1<<16)|(a2<<8)|a3);
450: }
451:
452: for (row = 4; row > 0; row--)
453: data[row-1] = tmp[row-1] ^ *(--k);
454: }
455: }
456:
457: #endif
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