+++ /dev/null
-/*
- * AES (Rijndael) cipher - decrypt
- *
- * Modifications to public domain implementation:
- * - support only 128-bit keys
- * - cleanup
- * - use C pre-processor to make it easier to change S table access
- * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
- * cost of reduced throughput (quite small difference on Pentium 4,
- * 10-25% when using -O1 or -O2 optimization)
- *
- * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Alternatively, this software may be distributed under the terms of BSD
- * license.
- *
- * See README and COPYING for more details.
- */
-
-#include "includes.h"
-
-#include "common.h"
-#include "crypto.h"
-#include "aes_i.h"
-
-/**
- * Expand the cipher key into the decryption key schedule.
- *
- * @return the number of rounds for the given cipher key size.
- */
-void rijndaelKeySetupDec(u32 rk[/*44*/], const u8 cipherKey[])
-{
- int Nr = 10, i, j;
- u32 temp;
-
- /* expand the cipher key: */
- rijndaelKeySetupEnc(rk, cipherKey);
- /* invert the order of the round keys: */
- for (i = 0, j = 4*Nr; i < j; i += 4, j -= 4) {
- temp = rk[i ]; rk[i ] = rk[j ]; rk[j ] = temp;
- temp = rk[i + 1]; rk[i + 1] = rk[j + 1]; rk[j + 1] = temp;
- temp = rk[i + 2]; rk[i + 2] = rk[j + 2]; rk[j + 2] = temp;
- temp = rk[i + 3]; rk[i + 3] = rk[j + 3]; rk[j + 3] = temp;
- }
- /* apply the inverse MixColumn transform to all round keys but the
- * first and the last: */
- for (i = 1; i < Nr; i++) {
- rk += 4;
- for (j = 0; j < 4; j++) {
- rk[j] = TD0_(TE4((rk[j] >> 24) )) ^
- TD1_(TE4((rk[j] >> 16) & 0xff)) ^
- TD2_(TE4((rk[j] >> 8) & 0xff)) ^
- TD3_(TE4((rk[j] ) & 0xff));
- }
- }
-}
-
-void * aes_decrypt_init(const u8 *key, size_t len)
-{
- u32 *rk;
- if (len != 16)
- return NULL;
- rk = os_malloc(AES_PRIV_SIZE);
- if (rk == NULL)
- return NULL;
- rijndaelKeySetupDec(rk, key);
- return rk;
-}
-
-static void rijndaelDecrypt(const u32 rk[/*44*/], const u8 ct[16], u8 pt[16])
-{
- u32 s0, s1, s2, s3, t0, t1, t2, t3;
- const int Nr = 10;
-#ifndef FULL_UNROLL
- int r;
-#endif /* ?FULL_UNROLL */
-
- /*
- * map byte array block to cipher state
- * and add initial round key:
- */
- s0 = GETU32(ct ) ^ rk[0];
- s1 = GETU32(ct + 4) ^ rk[1];
- s2 = GETU32(ct + 8) ^ rk[2];
- s3 = GETU32(ct + 12) ^ rk[3];
-
-#define ROUND(i,d,s) \
-d##0 = TD0(s##0) ^ TD1(s##3) ^ TD2(s##2) ^ TD3(s##1) ^ rk[4 * i]; \
-d##1 = TD0(s##1) ^ TD1(s##0) ^ TD2(s##3) ^ TD3(s##2) ^ rk[4 * i + 1]; \
-d##2 = TD0(s##2) ^ TD1(s##1) ^ TD2(s##0) ^ TD3(s##3) ^ rk[4 * i + 2]; \
-d##3 = TD0(s##3) ^ TD1(s##2) ^ TD2(s##1) ^ TD3(s##0) ^ rk[4 * i + 3]
-
-#ifdef FULL_UNROLL
-
- ROUND(1,t,s);
- ROUND(2,s,t);
- ROUND(3,t,s);
- ROUND(4,s,t);
- ROUND(5,t,s);
- ROUND(6,s,t);
- ROUND(7,t,s);
- ROUND(8,s,t);
- ROUND(9,t,s);
-
- rk += Nr << 2;
-
-#else /* !FULL_UNROLL */
-
- /* Nr - 1 full rounds: */
- r = Nr >> 1;
- for (;;) {
- ROUND(1,t,s);
- rk += 8;
- if (--r == 0)
- break;
- ROUND(0,s,t);
- }
-
-#endif /* ?FULL_UNROLL */
-
-#undef ROUND
-
- /*
- * apply last round and
- * map cipher state to byte array block:
- */
- s0 = TD41(t0) ^ TD42(t3) ^ TD43(t2) ^ TD44(t1) ^ rk[0];
- PUTU32(pt , s0);
- s1 = TD41(t1) ^ TD42(t0) ^ TD43(t3) ^ TD44(t2) ^ rk[1];
- PUTU32(pt + 4, s1);
- s2 = TD41(t2) ^ TD42(t1) ^ TD43(t0) ^ TD44(t3) ^ rk[2];
- PUTU32(pt + 8, s2);
- s3 = TD41(t3) ^ TD42(t2) ^ TD43(t1) ^ TD44(t0) ^ rk[3];
- PUTU32(pt + 12, s3);
-}
-
-void aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
-{
- rijndaelDecrypt(ctx, crypt, plain);
-}
-
-
-void aes_decrypt_deinit(void *ctx)
-{
- os_memset(ctx, 0, AES_PRIV_SIZE);
- os_free(ctx);
-}
projects / mech_eap.git / blobdiff