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00024 #include "includes.h"
00025
00026 #include "common.h"
00027 #include "crypto.h"
00028 #include "aes_i.h"
00029
00035 void rijndaelKeySetupDec(u32 rk[], const u8 cipherKey[])
00036 {
00037 int Nr = 10, i, j;
00038 u32 temp;
00039
00040
00041 rijndaelKeySetupEnc(rk, cipherKey);
00042
00043 for (i = 0, j = 4*Nr; i < j; i += 4, j -= 4) {
00044 temp = rk[i ]; rk[i ] = rk[j ]; rk[j ] = temp;
00045 temp = rk[i + 1]; rk[i + 1] = rk[j + 1]; rk[j + 1] = temp;
00046 temp = rk[i + 2]; rk[i + 2] = rk[j + 2]; rk[j + 2] = temp;
00047 temp = rk[i + 3]; rk[i + 3] = rk[j + 3]; rk[j + 3] = temp;
00048 }
00049
00050
00051 for (i = 1; i < Nr; i++) {
00052 rk += 4;
00053 for (j = 0; j < 4; j++) {
00054 rk[j] = TD0_(TE4((rk[j] >> 24) )) ^
00055 TD1_(TE4((rk[j] >> 16) & 0xff)) ^
00056 TD2_(TE4((rk[j] >> 8) & 0xff)) ^
00057 TD3_(TE4((rk[j] ) & 0xff));
00058 }
00059 }
00060 }
00061
00062 void * aes_decrypt_init(const u8 *key, size_t len)
00063 {
00064 u32 *rk;
00065 if (len != 16)
00066 return NULL;
00067 rk = os_malloc(AES_PRIV_SIZE);
00068 if (rk == NULL)
00069 return NULL;
00070 rijndaelKeySetupDec(rk, key);
00071 return rk;
00072 }
00073
00074 static void rijndaelDecrypt(const u32 rk[], const u8 ct[16], u8 pt[16])
00075 {
00076 u32 s0, s1, s2, s3, t0, t1, t2, t3;
00077 const int Nr = 10;
00078 #ifndef FULL_UNROLL
00079 int r;
00080 #endif
00081
00082
00083
00084
00085
00086 s0 = GETU32(ct ) ^ rk[0];
00087 s1 = GETU32(ct + 4) ^ rk[1];
00088 s2 = GETU32(ct + 8) ^ rk[2];
00089 s3 = GETU32(ct + 12) ^ rk[3];
00090
00091 #define ROUND(i,d,s) \
00092 d##0 = TD0(s##0) ^ TD1(s##3) ^ TD2(s##2) ^ TD3(s##1) ^ rk[4 * i]; \
00093 d##1 = TD0(s##1) ^ TD1(s##0) ^ TD2(s##3) ^ TD3(s##2) ^ rk[4 * i + 1]; \
00094 d##2 = TD0(s##2) ^ TD1(s##1) ^ TD2(s##0) ^ TD3(s##3) ^ rk[4 * i + 2]; \
00095 d##3 = TD0(s##3) ^ TD1(s##2) ^ TD2(s##1) ^ TD3(s##0) ^ rk[4 * i + 3]
00096
00097 #ifdef FULL_UNROLL
00098
00099 ROUND(1,t,s);
00100 ROUND(2,s,t);
00101 ROUND(3,t,s);
00102 ROUND(4,s,t);
00103 ROUND(5,t,s);
00104 ROUND(6,s,t);
00105 ROUND(7,t,s);
00106 ROUND(8,s,t);
00107 ROUND(9,t,s);
00108
00109 rk += Nr << 2;
00110
00111 #else
00112
00113
00114 r = Nr >> 1;
00115 for (;;) {
00116 ROUND(1,t,s);
00117 rk += 8;
00118 if (--r == 0)
00119 break;
00120 ROUND(0,s,t);
00121 }
00122
00123 #endif
00124
00125 #undef ROUND
00126
00127
00128
00129
00130
00131 s0 = TD41(t0) ^ TD42(t3) ^ TD43(t2) ^ TD44(t1) ^ rk[0];
00132 PUTU32(pt , s0);
00133 s1 = TD41(t1) ^ TD42(t0) ^ TD43(t3) ^ TD44(t2) ^ rk[1];
00134 PUTU32(pt + 4, s1);
00135 s2 = TD41(t2) ^ TD42(t1) ^ TD43(t0) ^ TD44(t3) ^ rk[2];
00136 PUTU32(pt + 8, s2);
00137 s3 = TD41(t3) ^ TD42(t2) ^ TD43(t1) ^ TD44(t0) ^ rk[3];
00138 PUTU32(pt + 12, s3);
00139 }
00140
00141 void aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
00142 {
00143 rijndaelDecrypt(ctx, crypt, plain);
00144 }
00145
00146
00147 void aes_decrypt_deinit(void *ctx)
00148 {
00149 os_memset(ctx, 0, AES_PRIV_SIZE);
00150 os_free(ctx);
00151 }