18d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt/* 28d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * AES (Rijndael) cipher - decrypt 38d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * 48d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * Modifications to public domain implementation: 58d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * - cleanup 68d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * - use C pre-processor to make it easier to change S table access 78d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at 88d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * cost of reduced throughput (quite small difference on Pentium 4, 98d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * 10-25% when using -O1 or -O2 optimization) 108d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * 119bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi> 128d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * 13c5ec7f57ead87efa365800228aa0b09a12d9e6c4Dmitry Shmidt * This software may be distributed under the terms of the BSD license. 14c5ec7f57ead87efa365800228aa0b09a12d9e6c4Dmitry Shmidt * See README for more details. 158d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt */ 168d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 178d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#include "includes.h" 188d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 198d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#include "common.h" 208d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#include "crypto.h" 218d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#include "aes_i.h" 228d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 238d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt/** 248d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * Expand the cipher key into the decryption key schedule. 258d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * 268d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * @return the number of rounds for the given cipher key size. 278d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt */ 289bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidtstatic int rijndaelKeySetupDec(u32 rk[], const u8 cipherKey[], int keyBits) 298d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt{ 309bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt int Nr, i, j; 318d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt u32 temp; 328d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 338d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* expand the cipher key: */ 349bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt Nr = rijndaelKeySetupEnc(rk, cipherKey, keyBits); 359bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt if (Nr < 0) 369bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt return Nr; 378d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* invert the order of the round keys: */ 388d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt for (i = 0, j = 4*Nr; i < j; i += 4, j -= 4) { 398d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt temp = rk[i ]; rk[i ] = rk[j ]; rk[j ] = temp; 408d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt temp = rk[i + 1]; rk[i + 1] = rk[j + 1]; rk[j + 1] = temp; 418d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt temp = rk[i + 2]; rk[i + 2] = rk[j + 2]; rk[j + 2] = temp; 428d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt temp = rk[i + 3]; rk[i + 3] = rk[j + 3]; rk[j + 3] = temp; 438d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt } 448d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* apply the inverse MixColumn transform to all round keys but the 458d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * first and the last: */ 468d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt for (i = 1; i < Nr; i++) { 478d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt rk += 4; 488d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt for (j = 0; j < 4; j++) { 498d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt rk[j] = TD0_(TE4((rk[j] >> 24) )) ^ 508d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt TD1_(TE4((rk[j] >> 16) & 0xff)) ^ 518d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt TD2_(TE4((rk[j] >> 8) & 0xff)) ^ 528d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt TD3_(TE4((rk[j] ) & 0xff)); 538d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt } 548d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt } 559bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt 569bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt return Nr; 578d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt} 588d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 598d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtvoid * aes_decrypt_init(const u8 *key, size_t len) 608d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt{ 618d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt u32 *rk; 629bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt int res; 638d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt rk = os_malloc(AES_PRIV_SIZE); 648d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt if (rk == NULL) 658d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt return NULL; 669bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt res = rijndaelKeySetupDec(rk, key, len * 8); 679bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt if (res < 0) { 689bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt os_free(rk); 699bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt return NULL; 709bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt } 719bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt rk[AES_PRIV_NR_POS] = res; 728d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt return rk; 738d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt} 748d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 759bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidtstatic void rijndaelDecrypt(const u32 rk[/*44*/], int Nr, const u8 ct[16], 769bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt u8 pt[16]) 778d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt{ 788d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt u32 s0, s1, s2, s3, t0, t1, t2, t3; 798d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#ifndef FULL_UNROLL 808d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt int r; 818d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#endif /* ?FULL_UNROLL */ 828d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 838d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* 848d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * map byte array block to cipher state 858d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * and add initial round key: 868d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt */ 878d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s0 = GETU32(ct ) ^ rk[0]; 888d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s1 = GETU32(ct + 4) ^ rk[1]; 898d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s2 = GETU32(ct + 8) ^ rk[2]; 908d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s3 = GETU32(ct + 12) ^ rk[3]; 918d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 928d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#define ROUND(i,d,s) \ 938d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtd##0 = TD0(s##0) ^ TD1(s##3) ^ TD2(s##2) ^ TD3(s##1) ^ rk[4 * i]; \ 948d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtd##1 = TD0(s##1) ^ TD1(s##0) ^ TD2(s##3) ^ TD3(s##2) ^ rk[4 * i + 1]; \ 958d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtd##2 = TD0(s##2) ^ TD1(s##1) ^ TD2(s##0) ^ TD3(s##3) ^ rk[4 * i + 2]; \ 968d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtd##3 = TD0(s##3) ^ TD1(s##2) ^ TD2(s##1) ^ TD3(s##0) ^ rk[4 * i + 3] 978d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 988d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#ifdef FULL_UNROLL 998d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1008d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(1,t,s); 1018d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(2,s,t); 1028d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(3,t,s); 1038d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(4,s,t); 1048d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(5,t,s); 1058d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(6,s,t); 1068d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(7,t,s); 1078d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(8,s,t); 1088d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(9,t,s); 1099bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt if (Nr > 10) { 1109bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt ROUND(10,s,t); 1119bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt ROUND(11,t,s); 1129bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt if (Nr > 12) { 1139bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt ROUND(12,s,t); 1149bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt ROUND(13,t,s); 1159bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt } 1169bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt } 1178d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1188d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt rk += Nr << 2; 1198d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1208d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#else /* !FULL_UNROLL */ 1218d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1228d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* Nr - 1 full rounds: */ 1238d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt r = Nr >> 1; 1248d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt for (;;) { 1258d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(1,t,s); 1268d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt rk += 8; 1278d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt if (--r == 0) 1288d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt break; 1298d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt ROUND(0,s,t); 1308d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt } 1318d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1328d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#endif /* ?FULL_UNROLL */ 1338d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1348d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt#undef ROUND 1358d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1368d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt /* 1378d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * apply last round and 1388d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt * map cipher state to byte array block: 1398d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt */ 1408d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s0 = TD41(t0) ^ TD42(t3) ^ TD43(t2) ^ TD44(t1) ^ rk[0]; 1418d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt PUTU32(pt , s0); 1428d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s1 = TD41(t1) ^ TD42(t0) ^ TD43(t3) ^ TD44(t2) ^ rk[1]; 1438d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt PUTU32(pt + 4, s1); 1448d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s2 = TD41(t2) ^ TD42(t1) ^ TD43(t0) ^ TD44(t3) ^ rk[2]; 1458d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt PUTU32(pt + 8, s2); 1468d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt s3 = TD41(t3) ^ TD42(t2) ^ TD43(t1) ^ TD44(t0) ^ rk[3]; 1478d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt PUTU32(pt + 12, s3); 1488d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt} 1498d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1508d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtvoid aes_decrypt(void *ctx, const u8 *crypt, u8 *plain) 1518d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt{ 1529bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt u32 *rk = ctx; 1539bce59c7fef20e34a05f04d1e33a4076083dca0cDmitry Shmidt rijndaelDecrypt(ctx, rk[AES_PRIV_NR_POS], crypt, plain); 1548d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt} 1558d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1568d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt 1578d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidtvoid aes_decrypt_deinit(void *ctx) 1588d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt{ 1598d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt os_memset(ctx, 0, AES_PRIV_SIZE); 1608d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt os_free(ctx); 1618d520ff1dc2da35cdca849e982051b86468016d8Dmitry Shmidt} 162