/** * Copyright (c) 2007, Cameron Rich * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the axTLS project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <stdlib.h> #include "sw_aes.h" /** * AES implementation - this is a small code version. There are much faster * versions around but they are much larger in size (i.e. they use large * submix tables). */ #include <string.h> #include <stdint.h> #include "sw_aes.h" #ifndef htonl #define htonl(a) ((((a) >> 24) & 0x000000ff) | (((a) >> 8) & 0x0000ff00) | (((a) << 8) & 0x00ff0000) | (((a) << 24) & 0xff000000)) #endif #ifndef ntohl #define ntohl(a) htonl((a)) #endif #ifndef htons #define htons(a) ((((a) >> 8) & 0x00ff) | (((a) << 8) & 0xff00)) #endif #ifndef ntohs #define ntohs(a) htons((a)) #endif #define rot1(x) (((x) << 24) | ((x) >> 8)) #define rot2(x) (((x) << 16) | ((x) >> 16)) #define rot3(x) (((x) << 8) | ((x) >> 24)) /* * This cute trick does 4 'mul by two' at once. Stolen from * Dr B. R. Gladman <brg@gladman.uk.net> but I'm sure the u-(u>>7) is * a standard graphics trick * The key to this is that we need to xor with 0x1b if the top bit is set. * a 1xxx xxxx 0xxx 0xxx First we mask the 7bit, * b 1000 0000 0000 0000 then we shift right by 7 putting the 7bit in 0bit, * c 0000 0001 0000 0000 we then subtract (c) from (b) * d 0111 1111 0000 0000 and now we and with our mask * e 0001 1011 0000 0000 */ #define mt 0x80808080 #define ml 0x7f7f7f7f #define mh 0xfefefefe #define mm 0x1b1b1b1b #define mul2(x,t) ((t)=((x)&mt), ((((x)+(x))&mh)^(((t)-((t)>>7))&mm))) #define inv_mix_col(x,f2,f4,f8,f9) ( (f2)=mul2(x,f2), (f4)=mul2(f2,f4), (f8)=mul2(f4,f8), (f9)=(x)^(f8), (f8)=((f2)^(f4)^(f8)), (f2)^=(f9), (f4)^=(f9), (f8)^=rot3(f2), (f8)^=rot2(f4), (f8)^rot1(f9)) /* * AES S-box */ static const uint8_t aes_sbox[256] = { 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, }; /* * AES is-box */ static const uint8_t aes_isbox[256] = { 0x52,0x09,0x6a,0xd5,0x30,0x36,0xa5,0x38, 0xbf,0x40,0xa3,0x9e,0x81,0xf3,0xd7,0xfb, 0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87, 0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb, 0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d, 0xee,0x4c,0x95,0x0b,0x42,0xfa,0xc3,0x4e, 0x08,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2, 0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25, 0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16, 0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92, 0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda, 0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84, 0x90,0xd8,0xab,0x00,0x8c,0xbc,0xd3,0x0a, 0xf7,0xe4,0x58,0x05,0xb8,0xb3,0x45,0x06, 0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0x0f,0x02, 0xc1,0xaf,0xbd,0x03,0x01,0x13,0x8a,0x6b, 0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea, 0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73, 0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85, 0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e, 0x47,0xf1,0x1a,0x71,0x1d,0x29,0xc5,0x89, 0x6f,0xb7,0x62,0x0e,0xaa,0x18,0xbe,0x1b, 0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20, 0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4, 0x1f,0xdd,0xa8,0x33,0x88,0x07,0xc7,0x31, 0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f, 0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0x0d, 0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef, 0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0, 0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61, 0x17,0x2b,0x04,0x7e,0xba,0x77,0xd6,0x26, 0xe1,0x69,0x14,0x63,0x55,0x21,0x0c,0x7d }; static const unsigned char Rcon[30]= { 0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80, 0x1b,0x36,0x6c,0xd8,0xab,0x4d,0x9a,0x2f, 0x5e,0xbc,0x63,0xc6,0x97,0x35,0x6a,0xd4, 0xb3,0x7d,0xfa,0xef,0xc5,0x91, }; /* ----- no more static functions ----- */ void AES_encrypt(const AES_CTX *ctx, uint32_t *data); void AES_decrypt(const AES_CTX *ctx, uint32_t *data); /* Perform doubling in Galois Field GF(2^8) using the irreducible polynomial x^8+x^4+x^3+x+1 */ static unsigned char AES_xtime(uint32_t x) { return (x&0x80) ? (x<<1)^0x1b : x<<1; } /** * Set up AES with the key/iv and cipher size. */ void AES_set_key(AES_CTX *ctx, const uint8_t *key, const uint8_t *iv, AES_MODE mode) { int i, ii; uint32_t *W, tmp, tmp2; const unsigned char *ip; int words; switch (mode) { case AES_MODE_128: i = 10; words = 4; break; case AES_MODE_256: i = 14; words = 8; break; default: /* fail silently */ return; } ctx->rounds = i; ctx->key_size = words; W = ctx->ks; for (i = 0; i < words; i+=2) { W[i+0]= ((uint32_t)key[ 0]<<24)| ((uint32_t)key[ 1]<<16)| ((uint32_t)key[ 2]<< 8)| ((uint32_t)key[ 3] ); W[i+1]= ((uint32_t)key[ 4]<<24)| ((uint32_t)key[ 5]<<16)| ((uint32_t)key[ 6]<< 8)| ((uint32_t)key[ 7] ); key += 8; } ip = Rcon; ii = 4 * (ctx->rounds+1); for (i = words; i<ii; i++) { tmp = W[i-1]; if ((i % words) == 0) { tmp2 =(uint32_t)aes_sbox[(tmp )&0xff]<< 8; tmp2|=(uint32_t)aes_sbox[(tmp>> 8)&0xff]<<16; tmp2|=(uint32_t)aes_sbox[(tmp>>16)&0xff]<<24; tmp2|=(uint32_t)aes_sbox[(tmp>>24) ]; tmp=tmp2^(((unsigned int)*ip)<<24); ip++; } if ((words == 8) && ((i % words) == 4)) { tmp2 =(uint32_t)aes_sbox[(tmp )&0xff] ; tmp2|=(uint32_t)aes_sbox[(tmp>> 8)&0xff]<< 8; tmp2|=(uint32_t)aes_sbox[(tmp>>16)&0xff]<<16; tmp2|=(uint32_t)aes_sbox[(tmp>>24) ]<<24; tmp=tmp2; } W[i]=W[i-words]^tmp; } /* copy the iv across */ memcpy(ctx->iv, iv, 16); } /** * Change a key for decryption. */ void AES_convert_key(AES_CTX *ctx) { int i; uint32_t *k,w,t1,t2,t3,t4; k = ctx->ks; k += 4; for (i= ctx->rounds*4; i > 4; i--) { w= *k; w = inv_mix_col(w,t1,t2,t3,t4); *k++ =w; } } /** * Encrypt a byte sequence (with a block size 16) using the AES cipher. */ void AES_cbc_encrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length) { int i; uint32_t tin[4], tout[4], iv[4]; memcpy(iv, ctx->iv, AES_IV_SIZE); for (i = 0; i < 4; i++) tout[i] = ntohl(iv[i]); for (length -= AES_BLOCKSIZE; length >= 0; length -= AES_BLOCKSIZE) { uint32_t msg_32[4]; uint32_t out_32[4]; memcpy(msg_32, msg, AES_BLOCKSIZE); msg += AES_BLOCKSIZE; for (i = 0; i < 4; i++) tin[i] = ntohl(msg_32[i])^tout[i]; AES_encrypt(ctx, tin); for (i = 0; i < 4; i++) { tout[i] = tin[i]; out_32[i] = htonl(tout[i]); } memcpy(out, out_32, AES_BLOCKSIZE); out += AES_BLOCKSIZE; } for (i = 0; i < 4; i++) iv[i] = htonl(tout[i]); memcpy(ctx->iv, iv, AES_IV_SIZE); } /** * Decrypt a byte sequence (with a block size 16) using the AES cipher. */ void AES_cbc_decrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length) { int i; uint32_t tin[4], xor[4], tout[4], data[4], iv[4]; memcpy(iv, ctx->iv, AES_IV_SIZE); for (i = 0; i < 4; i++) xor[i] = ntohl(iv[i]); for (length -= 16; length >= 0; length -= 16) { uint32_t msg_32[4]; uint32_t out_32[4]; memcpy(msg_32, msg, AES_BLOCKSIZE); msg += AES_BLOCKSIZE; for (i = 0; i < 4; i++) { tin[i] = ntohl(msg_32[i]); data[i] = tin[i]; } AES_decrypt(ctx, data); for (i = 0; i < 4; i++) { tout[i] = data[i]^xor[i]; xor[i] = tin[i]; out_32[i] = htonl(tout[i]); } memcpy(out, out_32, AES_BLOCKSIZE); out += AES_BLOCKSIZE; } for (i = 0; i < 4; i++) iv[i] = htonl(xor[i]); memcpy(ctx->iv, iv, AES_IV_SIZE); } /** * Encrypt a single block (16 bytes) of data */ void AES_encrypt(const AES_CTX *ctx, uint32_t *data) { /* To make this code smaller, generate the sbox entries on the fly. * This will have a really heavy effect upon performance. */ uint32_t tmp[4]; uint32_t tmp1, old_a0, a0, a1, a2, a3, row; int curr_rnd; int rounds = ctx->rounds; const uint32_t *k = ctx->ks; /* Pre-round key addition */ for (row = 0; row < 4; row++) data[row] ^= *(k++); /* Encrypt one block. */ for (curr_rnd = 0; curr_rnd < rounds; curr_rnd++) { /* Perform ByteSub and ShiftRow operations together */ for (row = 0; row < 4; row++) { a0 = (uint32_t)aes_sbox[(data[row%4]>>24)&0xFF]; a1 = (uint32_t)aes_sbox[(data[(row+1)%4]>>16)&0xFF]; a2 = (uint32_t)aes_sbox[(data[(row+2)%4]>>8)&0xFF]; a3 = (uint32_t)aes_sbox[(data[(row+3)%4])&0xFF]; /* Perform MixColumn iff not last round */ if (curr_rnd < (rounds - 1)) { tmp1 = a0 ^ a1 ^ a2 ^ a3; old_a0 = a0; a0 ^= tmp1 ^ AES_xtime(a0 ^ a1); a1 ^= tmp1 ^ AES_xtime(a1 ^ a2); a2 ^= tmp1 ^ AES_xtime(a2 ^ a3); a3 ^= tmp1 ^ AES_xtime(a3 ^ old_a0); } tmp[row] = ((a0 << 24) | (a1 << 16) | (a2 << 8) | a3); } /* KeyAddition - note that it is vital that this loop is separate from the MixColumn operation, which must be atomic...*/ for (row = 0; row < 4; row++) data[row] = tmp[row] ^ *(k++); } } /** * Decrypt a single block (16 bytes) of data */ void AES_decrypt(const AES_CTX *ctx, uint32_t *data) { uint32_t tmp[4]; uint32_t xt0,xt1,xt2,xt3,xt4,xt5,xt6; uint32_t a0, a1, a2, a3, row; int curr_rnd; int rounds = ctx->rounds; const uint32_t *k = ctx->ks + ((rounds+1)*4); /* pre-round key addition */ for (row=4; row > 0; row--) data[row-1] ^= *(--k); /* Decrypt one block */ for (curr_rnd = 0; curr_rnd < rounds; curr_rnd++) { /* Perform ByteSub and ShiftRow operations together */ for (row = 4; row > 0; row--) { a0 = aes_isbox[(data[(row+3)%4]>>24)&0xFF]; a1 = aes_isbox[(data[(row+2)%4]>>16)&0xFF]; a2 = aes_isbox[(data[(row+1)%4]>>8)&0xFF]; a3 = aes_isbox[(data[row%4])&0xFF]; /* Perform MixColumn iff not last round */ if (curr_rnd<(rounds-1)) { /* The MDS cofefficients (0x09, 0x0B, 0x0D, 0x0E) are quite large compared to encryption; this operation slows decryption down noticeably. */ xt0 = AES_xtime(a0^a1); xt1 = AES_xtime(a1^a2); xt2 = AES_xtime(a2^a3); xt3 = AES_xtime(a3^a0); xt4 = AES_xtime(xt0^xt1); xt5 = AES_xtime(xt1^xt2); xt6 = AES_xtime(xt4^xt5); xt0 ^= a1^a2^a3^xt4^xt6; xt1 ^= a0^a2^a3^xt5^xt6; xt2 ^= a0^a1^a3^xt4^xt6; xt3 ^= a0^a1^a2^xt5^xt6; tmp[row-1] = ((xt0<<24)|(xt1<<16)|(xt2<<8)|xt3); } else tmp[row-1] = ((a0<<24)|(a1<<16)|(a2<<8)|a3); } for (row = 4; row > 0; row--) data[row-1] = tmp[row-1] ^ *(--k); } }
/* crypto/aes/aes.h -*- mode:C; c-file-style: "eay" -*- */ #ifndef HEADER_AES_H #define HEADER_AES_H #include <stdint.h> /************************************************************************** * AES declarations **************************************************************************/ #define AES_MAXROUNDS 14 #define AES_BLOCKSIZE 16 #define AES_IV_SIZE 16 #ifndef htonl #define htonl(a) ((((a) >> 24) & 0x000000ff) | (((a) >> 8) & 0x0000ff00) | (((a) << 8) & 0x00ff0000) | (((a) << 24) & 0xff000000)) #endif #ifndef ntohl #define ntohl(a) htonl((a)) #endif typedef struct aes_key_st { uint16_t rounds; uint16_t key_size; uint32_t ks[(AES_MAXROUNDS+1)*8]; uint8_t iv[AES_IV_SIZE]; } AES_CTX; typedef enum { AES_MODE_128, AES_MODE_256 } AES_MODE; /** * Set up AES with the key/iv and cipher size. */ void AES_set_key(AES_CTX *ctx, const uint8_t *key, const uint8_t *iv, AES_MODE mode); /** * Encrypt a byte sequence (with a block size 16) using the AES cipher. */ void AES_cbc_encrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length); /** * Decrypt a byte sequence (with a block size 16) using the AES cipher. */ void AES_cbc_decrypt(AES_CTX *ks, const uint8_t *in, uint8_t *out, int length); /** * Change a key for decryption. */ void AES_convert_key(AES_CTX *ctx); /** * Decrypt a single block (16 bytes) of data */ void AES_decrypt(const AES_CTX *ctx, uint32_t *data); /** * Encrypt a single block (16 bytes) of data */ void AES_encrypt(const AES_CTX *ctx, uint32_t *data); #endif /* !HEADER_AES_H */
#define AES_MAXROUNDS 14 #define AES_BLOCKSIZE 16 #define AES_IV_SIZE 16 #define KEYSIZE 16 #define MSG_SIZE KEYSIZE * 4 static const uint8_t key[KEYSIZE] = { 0xff, 0xde, 0x00, 0xad, 0xff, 0xb0, 0x00, 0x0b, 0xff, 0xde, 0x00, 0xad, 0xff, 0xb0, 0x00, 0x0b }; static const uint8_t iv[KEYSIZE] = { 0xff, 0xc0, 0x00, 0xfe, 0xff, 0xc0, 0x00, 0x7d, 0xff, 0xc0, 0x00, 0xfe, 0xff, 0xc0, 0x00, 0x7d }; static const uint8_t original_msg[MSG_SIZE] = { 0xf4, 0xfc, 0xa2, 0xf4, 0x93, 0xfa, 0x64, 0xeb, 0x87, 0xca, 0xeb, 0x62, 0x90, 0x89, 0x34, 0xdb, 0x34, 0xe3, 0xf8, 0xc6, 0xd7, 0xf6, 0x89, 0xe7, 0xc0, 0x37, 0x43, 0xcd, 0x32, 0x69, 0xcd, 0xbd, 0x05, 0xec, 0x97, 0xbf, 0x05, 0x92, 0xc9, 0xf7, 0x8d, 0x4b, 0xb0, 0x88, 0x1a, 0xc2, 0x15, 0x2e, 0xba, 0x46, 0x58, 0xf9, 0x4d, 0x1f, 0xe9, 0xef, 0xa8, 0x6b, 0x5a, 0x6f, 0x8b, 0xe6, 0x7d, 0x51 }; static uint8_t out[MSG_SIZE] ; static uint8_t msg[MSG_SIZE] ; static AES_CTX context ; void test_setup() { } void test_clear() { uint8_t i =0; memcpy(msg, original_msg, MSG_SIZE); memset(out, 0, MSG_SIZE); memset(&context, 0, sizeof(context)); printf(" original_msg[%d] ",MSG_SIZE); for(i = 0 ; i<MSG_SIZE ; i++) { printf("%02x", original_msg[i]); } printf(" "); } void test_run() { uint8_t i =0; AES_set_key(&context, key, iv, AES_MODE_128); AES_cbc_encrypt(&context, msg, out, MSG_SIZE); printf(" out[%d] ",MSG_SIZE); for(i = 0 ; i<MSG_SIZE ; i++) { printf("%02x", out[i]); } printf(" "); memset(msg, 0, MSG_SIZE); memset(&context, 0, sizeof(context)); AES_set_key(&context, key, iv, AES_MODE_128); AES_convert_key(&context); AES_cbc_decrypt(&context, out, msg, MSG_SIZE); printf(" msg[%d] ",MSG_SIZE); for(i = 0 ; i<MSG_SIZE ; i++) { printf("%02x", msg[i]); } printf(" "); } int test_check() { return 0 == memcmp(msg, original_msg, MSG_SIZE); } int main(void) { test_clear(); test_run(); test_check(); for(;;) { } }
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