diff options
Diffstat (limited to 'third_party/srtp/crypto/cipher/aes.c')
| -rw-r--r-- | third_party/srtp/crypto/cipher/aes.c | 393 |
1 files changed, 296 insertions, 97 deletions
diff --git a/third_party/srtp/crypto/cipher/aes.c b/third_party/srtp/crypto/cipher/aes.c index f1286c36..e91e5254 100644 --- a/third_party/srtp/crypto/cipher/aes.c +++ b/third_party/srtp/crypto/cipher/aes.c @@ -43,6 +43,9 @@ * */ +#ifdef HAVE_CONFIG_H + #include <config.h> +#endif #include "aes.h" #include "err.h" @@ -1358,51 +1361,50 @@ static uint32_t U4[256] = { extern debug_module_t mod_aes_icm; -void -aes_expand_encryption_key(const v128_t *key, - aes_expanded_key_t expanded_key) { +static void +aes_128_expand_encryption_key(const uint8_t *key, + aes_expanded_key_t *expanded_key) { int i; gf2_8 rc; /* initialize round constant */ rc = 1; - expanded_key[0].v32[0] = key->v32[0]; - expanded_key[0].v32[1] = key->v32[1]; - expanded_key[0].v32[2] = key->v32[2]; - expanded_key[0].v32[3] = key->v32[3]; + expanded_key->num_rounds = 10; + + v128_copy_octet_string(&expanded_key->round[0], key); #if 0 debug_print(mod_aes_icm, - "expanded key[0]: %s", v128_hex_string(&expanded_key[0])); + "expanded key[0]: %s", v128_hex_string(&expanded_key->round[0])); #endif /* loop over round keys */ for (i=1; i < 11; i++) { /* munge first word of round key */ - expanded_key[i].v8[0] = aes_sbox[expanded_key[i-1].v8[13]] ^ rc; - expanded_key[i].v8[1] = aes_sbox[expanded_key[i-1].v8[14]]; - expanded_key[i].v8[2] = aes_sbox[expanded_key[i-1].v8[15]]; - expanded_key[i].v8[3] = aes_sbox[expanded_key[i-1].v8[12]]; + expanded_key->round[i].v8[0] = aes_sbox[expanded_key->round[i-1].v8[13]] ^ rc; + expanded_key->round[i].v8[1] = aes_sbox[expanded_key->round[i-1].v8[14]]; + expanded_key->round[i].v8[2] = aes_sbox[expanded_key->round[i-1].v8[15]]; + expanded_key->round[i].v8[3] = aes_sbox[expanded_key->round[i-1].v8[12]]; - expanded_key[i].v32[0] ^= expanded_key[i-1].v32[0]; + expanded_key->round[i].v32[0] ^= expanded_key->round[i-1].v32[0]; /* set remaining 32 bit words to the exor of the one previous with * the one four words previous */ - expanded_key[i].v32[1] = - expanded_key[i].v32[0] ^ expanded_key[i-1].v32[1]; + expanded_key->round[i].v32[1] = + expanded_key->round[i].v32[0] ^ expanded_key->round[i-1].v32[1]; - expanded_key[i].v32[2] = - expanded_key[i].v32[1] ^ expanded_key[i-1].v32[2]; + expanded_key->round[i].v32[2] = + expanded_key->round[i].v32[1] ^ expanded_key->round[i-1].v32[2]; - expanded_key[i].v32[3] = - expanded_key[i].v32[2] ^ expanded_key[i-1].v32[3]; + expanded_key->round[i].v32[3] = + expanded_key->round[i].v32[2] ^ expanded_key->round[i-1].v32[3]; #if 0 debug_print2(mod_aes_icm, - "expanded key[%d]: %s", i,v128_hex_string(&expanded_key[i])); + "expanded key[%d]: %s", i,v128_hex_string(&expanded_key->round[i])); #endif /* modify round constant */ @@ -1411,19 +1413,107 @@ aes_expand_encryption_key(const v128_t *key, } } -void -aes_expand_decryption_key(const v128_t *key, - aes_expanded_key_t expanded_key) { +static void +aes_256_expand_encryption_key(const unsigned char *key, + aes_expanded_key_t *expanded_key) { + int i; + gf2_8 rc; + + /* initialize round constant */ + rc = 1; + + expanded_key->num_rounds = 14; + + v128_copy_octet_string(&expanded_key->round[0], key); + v128_copy_octet_string(&expanded_key->round[1], key+16); + +#if 0 + debug_print(mod_aes_icm, + "expanded key[0]: %s", v128_hex_string(&expanded_key->round[0])); + debug_print(mod_aes_icm, + "expanded key[1]: %s", v128_hex_string(&expanded_key->round[1])); +#endif + + /* loop over rest of round keys */ + for (i=2; i < 15; i++) { + + /* munge first word of round key */ + if ((i & 1) == 0) { + expanded_key->round[i].v8[0] = aes_sbox[expanded_key->round[i-1].v8[13]] ^ rc; + expanded_key->round[i].v8[1] = aes_sbox[expanded_key->round[i-1].v8[14]]; + expanded_key->round[i].v8[2] = aes_sbox[expanded_key->round[i-1].v8[15]]; + expanded_key->round[i].v8[3] = aes_sbox[expanded_key->round[i-1].v8[12]]; + + /* modify round constant */ + rc = gf2_8_shift(rc); + } + else { + expanded_key->round[i].v8[0] = aes_sbox[expanded_key->round[i-1].v8[12]]; + expanded_key->round[i].v8[1] = aes_sbox[expanded_key->round[i-1].v8[13]]; + expanded_key->round[i].v8[2] = aes_sbox[expanded_key->round[i-1].v8[14]]; + expanded_key->round[i].v8[3] = aes_sbox[expanded_key->round[i-1].v8[15]]; + } + + expanded_key->round[i].v32[0] ^= expanded_key->round[i-2].v32[0]; + + /* set remaining 32 bit words to the exor of the one previous with + * the one eight words previous */ + + expanded_key->round[i].v32[1] = + expanded_key->round[i].v32[0] ^ expanded_key->round[i-2].v32[1]; + + expanded_key->round[i].v32[2] = + expanded_key->round[i].v32[1] ^ expanded_key->round[i-2].v32[2]; + + expanded_key->round[i].v32[3] = + expanded_key->round[i].v32[2] ^ expanded_key->round[i-2].v32[3]; + +#if 0 + debug_print2(mod_aes_icm, + "expanded key[%d]: %s", i,v128_hex_string(&expanded_key->round[i])); +#endif + + } +} + +err_status_t +aes_expand_encryption_key(const uint8_t *key, + int key_len, + aes_expanded_key_t *expanded_key) { + if (key_len == 16) { + aes_128_expand_encryption_key(key, expanded_key); + return err_status_ok; + } + else if (key_len == 24) { + /* AES-192 not yet supported */ + return err_status_bad_param; + } + else if (key_len == 32) { + aes_256_expand_encryption_key(key, expanded_key); + return err_status_ok; + } + else + return err_status_bad_param; +} + +err_status_t +aes_expand_decryption_key(const uint8_t *key, + int key_len, + aes_expanded_key_t *expanded_key) { int i; + err_status_t status; + int num_rounds = expanded_key->num_rounds; - aes_expand_encryption_key(key, expanded_key); + status = aes_expand_encryption_key(key, key_len, expanded_key); + if (status) + return status; /* invert the order of the round keys */ - for (i=0; i < 5; i++) { + for (i=0; i < num_rounds/2; i++) { v128_t tmp; - v128_copy(&tmp, &expanded_key[10-i]); - v128_copy(&expanded_key[10-i], &expanded_key[i]); - v128_copy(&expanded_key[i], &tmp); + v128_copy(&tmp, &expanded_key->round[num_rounds-i]); + v128_copy(&expanded_key->round[num_rounds-i], &expanded_key->round[i]); + v128_copy(&expanded_key->round[i], &tmp); } /* @@ -1434,68 +1524,101 @@ aes_expand_decryption_key(const v128_t *key, * followed by the T4 table (which cancels out the use of the sbox * in the U-tables) */ - for (i=1; i < 10; i++) { + for (i=1; i < num_rounds; i++) { #ifdef CPU_RISC uint32_t tmp; - tmp = expanded_key[i].v32[0]; - expanded_key[i].v32[0] = +#ifdef WORDS_BIGENDIAN + tmp = expanded_key->round[i].v32[0]; + expanded_key->round[i].v32[0] = U0[T4[(tmp >> 24) ] & 0xff] ^ U1[T4[(tmp >> 16) & 0xff] & 0xff] ^ U2[T4[(tmp >> 8) & 0xff] & 0xff] ^ U3[T4[(tmp) & 0xff] & 0xff]; - tmp = expanded_key[i].v32[1]; - expanded_key[i].v32[1] = + tmp = expanded_key->round[i].v32[1]; + expanded_key->round[i].v32[1] = U0[T4[(tmp >> 24) ] & 0xff] ^ U1[T4[(tmp >> 16) & 0xff] & 0xff] ^ U2[T4[(tmp >> 8) & 0xff] & 0xff] ^ U3[T4[(tmp) & 0xff] & 0xff]; - tmp = expanded_key[i].v32[2]; - expanded_key[i].v32[2] = + tmp = expanded_key->round[i].v32[2]; + expanded_key->round[i].v32[2] = U0[T4[(tmp >> 24) ] & 0xff] ^ U1[T4[(tmp >> 16) & 0xff] & 0xff] ^ U2[T4[(tmp >> 8) & 0xff] & 0xff] ^ U3[T4[(tmp) & 0xff] & 0xff]; - tmp = expanded_key[i].v32[3]; - expanded_key[i].v32[3] = + tmp = expanded_key->round[i].v32[3]; + expanded_key->round[i].v32[3] = U0[T4[(tmp >> 24) ] & 0xff] ^ U1[T4[(tmp >> 16) & 0xff] & 0xff] ^ U2[T4[(tmp >> 8) & 0xff] & 0xff] ^ U3[T4[(tmp) & 0xff] & 0xff]; +#else + tmp = expanded_key->round[i].v32[0]; + expanded_key->round[i].v32[0] = + U3[T4[(tmp >> 24) ] & 0xff] ^ + U2[T4[(tmp >> 16) & 0xff] & 0xff] ^ + U1[T4[(tmp >> 8) & 0xff] & 0xff] ^ + U0[T4[(tmp) & 0xff] & 0xff]; + + tmp = expanded_key->round[i].v32[1]; + expanded_key->round[i].v32[1] = + U3[T4[(tmp >> 24) ] & 0xff] ^ + U2[T4[(tmp >> 16) & 0xff] & 0xff] ^ + U1[T4[(tmp >> 8) & 0xff] & 0xff] ^ + U0[T4[(tmp) & 0xff] & 0xff]; + + tmp = expanded_key->round[i].v32[2]; + expanded_key->round[i].v32[2] = + U3[T4[(tmp >> 24) ] & 0xff] ^ + U2[T4[(tmp >> 16) & 0xff] & 0xff] ^ + U1[T4[(tmp >> 8) & 0xff] & 0xff] ^ + U0[T4[(tmp) & 0xff] & 0xff]; + + tmp = expanded_key->round[i].v32[3]; + expanded_key->round[i].v32[3] = + U3[T4[(tmp >> 24) ] & 0xff] ^ + U2[T4[(tmp >> 16) & 0xff] & 0xff] ^ + U1[T4[(tmp >> 8) & 0xff] & 0xff] ^ + U0[T4[(tmp) & 0xff] & 0xff]; +#endif /* WORDS_BIGENDIAN */ + #else /* assume CPU_CISC */ uint32_t c0, c1, c2, c3; - c0 = U0[aes_sbox[expanded_key[i].v8[0]]] - ^ U1[aes_sbox[expanded_key[i].v8[1]]] - ^ U2[aes_sbox[expanded_key[i].v8[2]]] - ^ U3[aes_sbox[expanded_key[i].v8[3]]]; + c0 = U0[aes_sbox[expanded_key->round[i].v8[0]]] + ^ U1[aes_sbox[expanded_key->round[i].v8[1]]] + ^ U2[aes_sbox[expanded_key->round[i].v8[2]]] + ^ U3[aes_sbox[expanded_key->round[i].v8[3]]]; - c1 = U0[aes_sbox[expanded_key[i].v8[4]]] - ^ U1[aes_sbox[expanded_key[i].v8[5]]] - ^ U2[aes_sbox[expanded_key[i].v8[6]]] - ^ U3[aes_sbox[expanded_key[i].v8[7]]]; + c1 = U0[aes_sbox[expanded_key->round[i].v8[4]]] + ^ U1[aes_sbox[expanded_key->round[i].v8[5]]] + ^ U2[aes_sbox[expanded_key->round[i].v8[6]]] + ^ U3[aes_sbox[expanded_key->round[i].v8[7]]]; - c2 = U0[aes_sbox[expanded_key[i].v8[8]]] - ^ U1[aes_sbox[expanded_key[i].v8[9]]] - ^ U2[aes_sbox[expanded_key[i].v8[10]]] - ^ U3[aes_sbox[expanded_key[i].v8[11]]]; + c2 = U0[aes_sbox[expanded_key->round[i].v8[8]]] + ^ U1[aes_sbox[expanded_key->round[i].v8[9]]] + ^ U2[aes_sbox[expanded_key->round[i].v8[10]]] + ^ U3[aes_sbox[expanded_key->round[i].v8[11]]]; - c3 = U0[aes_sbox[expanded_key[i].v8[12]]] - ^ U1[aes_sbox[expanded_key[i].v8[13]]] - ^ U2[aes_sbox[expanded_key[i].v8[14]]] - ^ U3[aes_sbox[expanded_key[i].v8[15]]]; + c3 = U0[aes_sbox[expanded_key->round[i].v8[12]]] + ^ U1[aes_sbox[expanded_key->round[i].v8[13]]] + ^ U2[aes_sbox[expanded_key->round[i].v8[14]]] + ^ U3[aes_sbox[expanded_key->round[i].v8[15]]]; - expanded_key[i].v32[0] = c0; - expanded_key[i].v32[1] = c1; - expanded_key[i].v32[2] = c2; - expanded_key[i].v32[3] = c3; + expanded_key->round[i].v32[0] = c0; + expanded_key->round[i].v32[1] = c1; + expanded_key->round[i].v32[2] = c2; + expanded_key->round[i].v32[3] = c3; #endif } + + return err_status_ok; } #ifdef CPU_CISC @@ -1676,7 +1799,6 @@ aes_inv_round(v128_t *state, const v128_t *round_key) { of state, using the tables U0, U1, U2, U3 */ #ifdef WORDS_BIGENDIAN - /* FIX! WRong indexes */ column0 = U0[state->v32[0] >> 24] ^ U1[(state->v32[3] >> 16) & 0xff] ^ U2[(state->v32[2] >> 8) & 0xff] ^ U3[state->v32[1] & 0xff]; @@ -1689,17 +1811,17 @@ aes_inv_round(v128_t *state, const v128_t *round_key) { column3 = U0[state->v32[3] >> 24] ^ U1[(state->v32[2] >> 16) & 0xff] ^ U2[(state->v32[1] >> 8) & 0xff] ^ U3[state->v32[0] & 0xff]; #else - column0 = U0[state->v32[0] & 0xff] ^ U1[(state->v32[1] >> 8) & 0xff] - ^ U2[(state->v32[2] >> 16) & 0xff] ^ U3[state->v32[3] >> 24]; + column0 = U0[state->v32[0] & 0xff] ^ U1[(state->v32[3] >> 8) & 0xff] + ^ U2[(state->v32[2] >> 16) & 0xff] ^ U3[(state->v32[1] >> 24) & 0xff]; - column1 = U0[state->v32[1] & 0xff] ^ U1[(state->v32[2] >> 8) & 0xff] - ^ U2[(state->v32[3] >> 16) & 0xff] ^ U3[state->v32[0] >> 24]; + column1 = U0[state->v32[1] & 0xff] ^ U1[(state->v32[0] >> 8) & 0xff] + ^ U2[(state->v32[3] >> 16) & 0xff] ^ U3[(state->v32[2] >> 24) & 0xff]; - column2 = U0[state->v32[2] & 0xff] ^ U1[(state->v32[3] >> 8) & 0xff] - ^ U2[(state->v32[0] >> 16) & 0xff] ^ U3[state->v32[1] >> 24]; + column2 = U0[state->v32[2] & 0xff] ^ U1[(state->v32[1] >> 8) & 0xff] + ^ U2[(state->v32[0] >> 16) & 0xff] ^ U3[(state->v32[3] >> 24) & 0xff]; - column3 = U0[state->v32[3] & 0xff] ^ U1[(state->v32[0] >> 8) & 0xff] - ^ U2[(state->v32[1] >> 16) & 0xff] ^ U3[state->v32[2] >> 24]; + column3 = U0[state->v32[3] & 0xff] ^ U1[(state->v32[2] >> 8) & 0xff] + ^ U2[(state->v32[1] >> 16) & 0xff] ^ U3[(state->v32[0] >> 24) & 0xff]; #endif /* WORDS_BIGENDIAN */ state->v32[0] = column0 ^ round_key->v32[0]; @@ -1713,6 +1835,7 @@ static inline void aes_final_round(v128_t *state, const v128_t *round_key) { uint32_t tmp0, tmp1, tmp2, tmp3; +#ifdef WORDS_BIGENDIAN tmp0 = (T4[(state->v32[0] >> 24)] & 0xff000000) ^ (T4[(state->v32[1] >> 16) & 0xff] & 0x00ff0000) ^ (T4[(state->v32[2] >> 8) & 0xff] & 0x0000ff00) @@ -1736,6 +1859,31 @@ aes_final_round(v128_t *state, const v128_t *round_key) { ^ (T4[(state->v32[1] >> 8) & 0xff] & 0x0000ff00) ^ (T4[(state->v32[2] ) & 0xff] & 0x000000ff) ^ round_key->v32[3]; +#else + tmp0 = (T4[(state->v32[3] >> 24)] & 0xff000000) + ^ (T4[(state->v32[2] >> 16) & 0xff] & 0x00ff0000) + ^ (T4[(state->v32[1] >> 8) & 0xff] & 0x0000ff00) + ^ (T4[(state->v32[0] ) & 0xff] & 0x000000ff) + ^ round_key->v32[0]; + + tmp1 = (T4[(state->v32[0] >> 24)] & 0xff000000) + ^ (T4[(state->v32[3] >> 16) & 0xff] & 0x00ff0000) + ^ (T4[(state->v32[2] >> 8) & 0xff] & 0x0000ff00) + ^ (T4[(state->v32[1] ) & 0xff] & 0x000000ff) + ^ round_key->v32[1]; + + tmp2 = (T4[(state->v32[1] >> 24)] & 0xff000000) + ^ (T4[(state->v32[0] >> 16) & 0xff] & 0x00ff0000) + ^ (T4[(state->v32[3] >> 8) & 0xff] & 0x0000ff00) + ^ (T4[(state->v32[2] ) & 0xff] & 0x000000ff) + ^ round_key->v32[2]; + + tmp3 = (T4[(state->v32[2] >> 24)] & 0xff000000) + ^ (T4[(state->v32[1] >> 16) & 0xff] & 0x00ff0000) + ^ (T4[(state->v32[0] >> 8) & 0xff] & 0x0000ff00) + ^ (T4[(state->v32[3] ) & 0xff] & 0x000000ff) + ^ round_key->v32[3]; +#endif /* WORDS_BIGENDIAN */ state->v32[0] = tmp0; state->v32[1] = tmp1; @@ -1748,6 +1896,7 @@ static inline void aes_inv_final_round(v128_t *state, const v128_t *round_key) { uint32_t tmp0, tmp1, tmp2, tmp3; +#ifdef WORDS_BIGENDIAN tmp0 = (U4[(state->v32[0] >> 24)] & 0xff000000) ^ (U4[(state->v32[3] >> 16) & 0xff] & 0x00ff0000) ^ (U4[(state->v32[2] >> 8) & 0xff] & 0x0000ff00) @@ -1771,6 +1920,31 @@ aes_inv_final_round(v128_t *state, const v128_t *round_key) { ^ (U4[(state->v32[1] >> 8) & 0xff] & 0x0000ff00) ^ (U4[(state->v32[0] ) & 0xff] & 0x000000ff) ^ round_key->v32[3]; +#else + tmp0 = (U4[(state->v32[1] >> 24)] & 0xff000000) + ^ (U4[(state->v32[2] >> 16) & 0xff] & 0x00ff0000) + ^ (U4[(state->v32[3] >> 8) & 0xff] & 0x0000ff00) + ^ (U4[(state->v32[0] ) & 0xff] & 0x000000ff) + ^ round_key->v32[0]; + + tmp1 = (U4[(state->v32[2] >> 24)] & 0xff000000) + ^ (U4[(state->v32[3] >> 16) & 0xff] & 0x00ff0000) + ^ (U4[(state->v32[0] >> 8) & 0xff] & 0x0000ff00) + ^ (U4[(state->v32[1] ) & 0xff] & 0x000000ff) + ^ round_key->v32[1]; + + tmp2 = (U4[(state->v32[3] >> 24)] & 0xff000000) + ^ (U4[(state->v32[0] >> 16) & 0xff] & 0x00ff0000) + ^ (U4[(state->v32[1] >> 8) & 0xff] & 0x0000ff00) + ^ (U4[(state->v32[2] ) & 0xff] & 0x000000ff) + ^ round_key->v32[2]; + + tmp3 = (U4[(state->v32[0] >> 24)] & 0xff000000) + ^ (U4[(state->v32[1] >> 16) & 0xff] & 0x00ff0000) + ^ (U4[(state->v32[2] >> 8) & 0xff] & 0x0000ff00) + ^ (U4[(state->v32[3] ) & 0xff] & 0x000000ff) + ^ round_key->v32[3]; +#endif /* WORDS_BIGENDIAN */ state->v32[0] = tmp0; state->v32[1] = tmp1; @@ -1910,42 +2084,67 @@ aes_inv_final_round(v128_t *state, const v128_t *round_key) { void -aes_encrypt(v128_t *plaintext, const aes_expanded_key_t exp_key) { +aes_encrypt(v128_t *plaintext, const aes_expanded_key_t *exp_key) { /* add in the subkey */ - v128_xor_eq(plaintext, exp_key + 0); - - /* now do nine rounds */ - aes_round(plaintext, exp_key + 1); - aes_round(plaintext, exp_key + 2); - aes_round(plaintext, exp_key + 3); - aes_round(plaintext, exp_key + 4); - aes_round(plaintext, exp_key + 5); - aes_round(plaintext, exp_key + 6); - aes_round(plaintext, exp_key + 7); - aes_round(plaintext, exp_key + 8); - aes_round(plaintext, exp_key + 9); - /* the last round is different */ - - aes_final_round(plaintext, exp_key + 10); + v128_xor_eq(plaintext, &exp_key->round[0]); + + /* now do the rounds */ + aes_round(plaintext, &exp_key->round[1]); + aes_round(plaintext, &exp_key->round[2]); + aes_round(plaintext, &exp_key->round[3]); + aes_round(plaintext, &exp_key->round[4]); + aes_round(plaintext, &exp_key->round[5]); + aes_round(plaintext, &exp_key->round[6]); + aes_round(plaintext, &exp_key->round[7]); + aes_round(plaintext, &exp_key->round[8]); + aes_round(plaintext, &exp_key->round[9]); + if (exp_key->num_rounds == 10) { + aes_final_round(plaintext, &exp_key->round[10]); + } + else if (exp_key->num_rounds == 12) { + aes_round(plaintext, &exp_key->round[10]); + aes_round(plaintext, &exp_key->round[11]); + aes_final_round(plaintext, &exp_key->round[12]); + } + else if (exp_key->num_rounds == 14) { + aes_round(plaintext, &exp_key->round[10]); + aes_round(plaintext, &exp_key->round[11]); + aes_round(plaintext, &exp_key->round[12]); + aes_round(plaintext, &exp_key->round[13]); + aes_final_round(plaintext, &exp_key->round[14]); + } } void -aes_decrypt(v128_t *plaintext, const aes_expanded_key_t exp_key) { +aes_decrypt(v128_t *plaintext, const aes_expanded_key_t *exp_key) { /* add in the subkey */ - v128_xor_eq(plaintext, exp_key + 0); - - /* now do nine rounds */ - aes_inv_round(plaintext, exp_key + 1); - aes_inv_round(plaintext, exp_key + 2); - aes_inv_round(plaintext, exp_key + 3); - aes_inv_round(plaintext, exp_key + 4); - aes_inv_round(plaintext, exp_key + 5); - aes_inv_round(plaintext, exp_key + 6); - aes_inv_round(plaintext, exp_key + 7); - aes_inv_round(plaintext, exp_key + 8); - aes_inv_round(plaintext, exp_key + 9); - /* the last round is different */ - aes_inv_final_round(plaintext, exp_key + 10); + v128_xor_eq(plaintext, &exp_key->round[0]); + + /* now do the rounds */ + aes_inv_round(plaintext, &exp_key->round[1]); + aes_inv_round(plaintext, &exp_key->round[2]); + aes_inv_round(plaintext, &exp_key->round[3]); + aes_inv_round(plaintext, &exp_key->round[4]); + aes_inv_round(plaintext, &exp_key->round[5]); + aes_inv_round(plaintext, &exp_key->round[6]); + aes_inv_round(plaintext, &exp_key->round[7]); + aes_inv_round(plaintext, &exp_key->round[8]); + aes_inv_round(plaintext, &exp_key->round[9]); + if (exp_key->num_rounds == 10) { + aes_inv_final_round(plaintext, &exp_key->round[10]); + } + else if (exp_key->num_rounds == 12) { + aes_inv_round(plaintext, &exp_key->round[10]); + aes_inv_round(plaintext, &exp_key->round[11]); + aes_inv_final_round(plaintext, &exp_key->round[12]); + } + else if (exp_key->num_rounds == 14) { + aes_inv_round(plaintext, &exp_key->round[10]); + aes_inv_round(plaintext, &exp_key->round[11]); + aes_inv_round(plaintext, &exp_key->round[12]); + aes_inv_round(plaintext, &exp_key->round[13]); + aes_inv_final_round(plaintext, &exp_key->round[14]); + } } |