/**************************************************************************** * crypto/aes.c * * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ * Extracted from the CC3000 Host Driver Implementation. * * 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 Texas Instruments Incorporated 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include /**************************************************************************** * Private Data ****************************************************************************/ /* Forward sbox */ static const uint8_t g_sbox[256] = { /* 0 1 2 3 4 5 6 7 8 9 * A B C D E F */ 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, /* 0 */ 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, /* 1 */ 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, /* 2 */ 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, /* 3 */ 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, /* 4 */ 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, /* 5 */ 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, /* 6 */ 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, /* 7 */ 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, /* 8 */ 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, /* 9 */ 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, /* A */ 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, /* B */ 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, /* C */ 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, /* D */ 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, /* E */ 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 /* F */ }; /* Inverse sbox */ static const uint8_t g_rsbox[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 }; /* Round constant */ static const uint8_t g_rcon[11] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; static struct aes_state_s g_aes_state; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: expand_key * * Description: * Expend a 16 bytes key for AES128 implementation * * Input Parameters: * key AES128 key - 16 bytes * expanded_key expanded AES128 key * * Returned Value: * None * ****************************************************************************/ static void expand_key(FAR uint8_t *expanded_key, FAR const uint8_t *key) { uint16_t buf1; uint16_t ii; for (ii = 0; ii < 16; ii++) { expanded_key[ii] = key[ii]; } for (ii = 1; ii < 11; ii++) { buf1 = expanded_key[ii * 16 - 4]; expanded_key[ii * 16 + 0] = g_sbox[expanded_key[ii *16 - 3]] ^ expanded_key[(ii - 1) * 16 + 0] ^ g_rcon[ii]; expanded_key[ii * 16 + 1] = g_sbox[expanded_key[ii *16 - 2]] ^ expanded_key[(ii - 1) * 16 + 1]; expanded_key[ii * 16 + 2] = g_sbox[expanded_key[ii *16 - 1]] ^ expanded_key[(ii - 1) * 16 + 2]; expanded_key[ii * 16 + 3] = g_sbox[buf1] ^ expanded_key[(ii - 1) * 16 + 3]; expanded_key[ii * 16 + 4] = expanded_key[(ii - 1) * 16 + 4] ^ expanded_key[ii * 16 + 0]; expanded_key[ii * 16 + 5] = expanded_key[(ii - 1) * 16 + 5] ^ expanded_key[ii * 16 + 1]; expanded_key[ii * 16 + 6] = expanded_key[(ii - 1) * 16 + 6] ^ expanded_key[ii * 16 + 2]; expanded_key[ii * 16 + 7] = expanded_key[(ii - 1) * 16 + 7] ^ expanded_key[ii * 16 + 3]; expanded_key[ii * 16 + 8] = expanded_key[(ii - 1) * 16 + 8] ^ expanded_key[ii * 16 + 4]; expanded_key[ii * 16 + 9] = expanded_key[(ii - 1) * 16 + 9] ^ expanded_key[ii * 16 + 5]; expanded_key[ii * 16 +10] = expanded_key[(ii - 1) * 16 +10] ^ expanded_key[ii * 16 + 6]; expanded_key[ii * 16 +11] = expanded_key[(ii - 1) * 16 +11] ^ expanded_key[ii * 16 + 7]; expanded_key[ii * 16 +12] = expanded_key[(ii - 1) * 16 +12] ^ expanded_key[ii * 16 + 8]; expanded_key[ii * 16 +13] = expanded_key[(ii - 1) * 16 +13] ^ expanded_key[ii * 16 + 9]; expanded_key[ii * 16 +14] = expanded_key[(ii - 1) * 16 +14] ^ expanded_key[ii * 16 +10]; expanded_key[ii * 16 +15] = expanded_key[(ii - 1) * 16 +15] ^ expanded_key[ii * 16 +11]; } } /**************************************************************************** * Name: galois_mul2 * * Description: * Multiply by 2 in the galois field * * Input Parameters: * value argument to multiply * * Returned Value: * Multiplied argument * ****************************************************************************/ static uint8_t galois_mul2(uint8_t value) { if (value >> 7) { value = value << 1; return (value ^ 0x1b); } else { return value << 1; } } /**************************************************************************** * Name: aes_encr * * Description: * Internal implementation of AES128 encryption. * Straight forward aes encryption implementation. First the group of * operations: * * - addRoundKey * - subbytes * - shiftrows * - mixcolums * * is executed 9 times, after this addroundkey to finish the 9th round, * after that the 10th round without mixcolums no further subfunctions * to save cycles for function calls no structuring with "for (....)" * to save cycles. * * Input Parameters: * expanded_key expanded AES128 key * state 16 bytes of plain text and cipher text * * Returned Value: * None * ****************************************************************************/ static void aes_encr(FAR uint8_t *state, FAR const uint8_t *expanded_key) { uint8_t buf1; uint8_t buf2; uint8_t buf3; uint8_t round; for (round = 0; round < 9; round ++) { /* addroundkey, sbox and shiftrows */ /* Row 0 */ state[0] = g_sbox[(state[0] ^ expanded_key[(round * 16)])]; state[4] = g_sbox[(state[4] ^ expanded_key[(round * 16) + 4])]; state[8] = g_sbox[(state[8] ^ expanded_key[(round * 16) + 8])]; state[12] = g_sbox[(state[12] ^ expanded_key[(round * 16) + 12])]; /* Row 1 */ buf1 = state[1] ^ expanded_key[(round * 16) + 1]; state[1] = g_sbox[(state[5] ^ expanded_key[(round * 16) + 5])]; state[5] = g_sbox[(state[9] ^ expanded_key[(round * 16) + 9])]; state[9] = g_sbox[(state[13] ^ expanded_key[(round * 16) + 13])]; state[13] = g_sbox[buf1]; /* Row 2 */ buf1 = state[2] ^ expanded_key[(round * 16) + 2]; buf2 = state[6] ^ expanded_key[(round * 16) + 6]; state[2] = g_sbox[(state[10] ^ expanded_key[(round * 16) + 10])]; state[6] = g_sbox[(state[14] ^ expanded_key[(round * 16) + 14])]; state[10] = g_sbox[buf1]; state[14] = g_sbox[buf2]; /* Row 3 */ buf1 = state[15] ^ expanded_key[(round * 16) + 15]; state[15] = g_sbox[(state[11] ^ expanded_key[(round * 16) + 11])]; state[11] = g_sbox[(state[7] ^ expanded_key[(round * 16) + 7])]; state[7] = g_sbox[(state[3] ^ expanded_key[(round * 16) + 3])]; state[3] = g_sbox[buf1]; /* mixcolums */ /* Col1 */ buf1 = state[0] ^ state[1] ^ state[2] ^ state[3]; buf2 = state[0]; buf3 = state[0] ^ state[1]; buf3 = galois_mul2(buf3); state[0] = state[0] ^ buf3 ^ buf1; buf3 = state[1] ^ state[2]; buf3 = galois_mul2(buf3); state[1] = state[1] ^ buf3 ^ buf1; buf3 = state[2] ^ state[3]; buf3 = galois_mul2(buf3); state[2] = state[2] ^ buf3 ^ buf1; buf3 = state[3] ^ buf2; buf3 = galois_mul2(buf3); state[3] = state[3] ^ buf3 ^ buf1; /* Col2 */ buf1 = state[4] ^ state[5] ^ state[6] ^ state[7]; buf2 = state[4]; buf3 = state[4] ^ state[5]; buf3 = galois_mul2(buf3); state[4] = state[4] ^ buf3 ^ buf1; buf3 = state[5] ^ state[6]; buf3 = galois_mul2(buf3); state[5] = state[5] ^ buf3 ^ buf1; buf3 = state[6] ^ state[7]; buf3 = galois_mul2(buf3); state[6] = state[6] ^ buf3 ^ buf1; buf3 = state[7] ^ buf2; buf3 = galois_mul2(buf3); state[7] = state[7] ^ buf3 ^ buf1; /* Col3 */ buf1 = state[8] ^ state[9] ^ state[10] ^ state[11]; buf2 = state[8]; buf3 = state[8] ^ state[9]; buf3 = galois_mul2(buf3); state[8] = state[8] ^ buf3 ^ buf1; buf3 = state[9] ^ state[10]; buf3 = galois_mul2(buf3); state[9] = state[9] ^ buf3 ^ buf1; buf3 = state[10] ^ state[11]; buf3 = galois_mul2(buf3); state[10] = state[10] ^ buf3 ^ buf1; buf3 = state[11] ^ buf2; buf3 = galois_mul2(buf3); state[11] = state[11] ^ buf3 ^ buf1; /* Col4 */ buf1 = state[12] ^ state[13] ^ state[14] ^ state[15]; buf2 = state[12]; buf3 = state[12] ^ state[13]; buf3 = galois_mul2(buf3); state[12] = state[12] ^ buf3 ^ buf1; buf3 = state[13] ^ state[14]; buf3 = galois_mul2(buf3); state[13] = state[13] ^ buf3 ^ buf1; buf3 = state[14] ^ state[15]; buf3 = galois_mul2(buf3); state[14] = state[14] ^ buf3 ^ buf1; buf3 = state[15] ^ buf2; buf3 = galois_mul2(buf3); state[15] = state[15] ^ buf3 ^ buf1; } /* 10th round without mixcols */ state[0] = g_sbox[(state[0] ^ expanded_key[(round * 16)])]; state[4] = g_sbox[(state[4] ^ expanded_key[(round * 16) + 4])]; state[8] = g_sbox[(state[8] ^ expanded_key[(round * 16) + 8])]; state[12] = g_sbox[(state[12] ^ expanded_key[(round * 16) + 12])]; /* Row 1 */ buf1 = state[1] ^ expanded_key[(round * 16) + 1]; state[1] = g_sbox[(state[5] ^ expanded_key[(round * 16) + 5])]; state[5] = g_sbox[(state[9] ^ expanded_key[(round * 16) + 9])]; state[9] = g_sbox[(state[13] ^ expanded_key[(round * 16) + 13])]; state[13] = g_sbox[buf1]; /* Row 2 */ buf1 = state[2] ^ expanded_key[(round * 16) + 2]; buf2 = state[6] ^ expanded_key[(round * 16) + 6]; state[2] = g_sbox[(state[10] ^ expanded_key[(round * 16) + 10])]; state[6] = g_sbox[(state[14] ^ expanded_key[(round * 16) + 14])]; state[10] = g_sbox[buf1]; state[14] = g_sbox[buf2]; /* Row 3 */ buf1 = state[15] ^ expanded_key[(round * 16) + 15]; state[15] = g_sbox[(state[11] ^ expanded_key[(round * 16) + 11])]; state[11] = g_sbox[(state[7] ^ expanded_key[(round * 16) + 7])]; state[7] = g_sbox[(state[3] ^ expanded_key[(round * 16) + 3])]; state[3] = g_sbox[buf1]; /* Last addroundkey */ state[0] ^= expanded_key[160]; state[1] ^= expanded_key[161]; state[2] ^= expanded_key[162]; state[3] ^= expanded_key[163]; state[4] ^= expanded_key[164]; state[5] ^= expanded_key[165]; state[6] ^= expanded_key[166]; state[7] ^= expanded_key[167]; state[8] ^= expanded_key[168]; state[9] ^= expanded_key[169]; state[10] ^= expanded_key[170]; state[11] ^= expanded_key[171]; state[12] ^= expanded_key[172]; state[13] ^= expanded_key[173]; state[14] ^= expanded_key[174]; state[15] ^= expanded_key[175]; } /**************************************************************************** * Name: aes_decr * * Description: * Internal implementation of AES128 decryption. * Straight forward aes decryption implementation. The order of substeps is * the exact reverse of decryption inverse functions: * * - addRoundKey is its own inverse * - rsbox is inverse of sbox * - rightshift instead of leftshift * - invMixColumns = barreto + mixColumns * * No further subfunctions to save cycles for function calls no structuring * with "for (....)" to save cycles * * Input Parameters: * expanded_key expanded AES128 key * state 16 bytes of cipher text and plain text * * Returned Value: * None * ****************************************************************************/ static void aes_decr(FAR uint8_t *state, FAR const uint8_t *expanded_key) { uint8_t buf1; uint8_t buf2; uint8_t buf3; int8_t round; round = 9; /* Initial addroundkey */ state[0] ^= expanded_key[160]; state[1] ^= expanded_key[161]; state[2] ^= expanded_key[162]; state[3] ^= expanded_key[163]; state[4] ^= expanded_key[164]; state[5] ^= expanded_key[165]; state[6] ^= expanded_key[166]; state[7] ^= expanded_key[167]; state[8] ^= expanded_key[168]; state[9] ^= expanded_key[169]; state[10] ^= expanded_key[170]; state[11] ^= expanded_key[171]; state[12] ^= expanded_key[172]; state[13] ^= expanded_key[173]; state[14] ^= expanded_key[174]; state[15] ^= expanded_key[175]; /* 10th round without mixcols */ state[0] = g_rsbox[state[0]] ^ expanded_key[(round * 16)]; state[4] = g_rsbox[state[4]] ^ expanded_key[(round * 16) + 4]; state[8] = g_rsbox[state[8]] ^ expanded_key[(round * 16) + 8]; state[12] = g_rsbox[state[12]] ^ expanded_key[(round * 16) + 12]; /* Row 1 */ buf1 = g_rsbox[state[13]] ^ expanded_key[(round * 16) + 1]; state[13] = g_rsbox[state[9]] ^ expanded_key[(round * 16) + 13]; state[9] = g_rsbox[state[5]] ^ expanded_key[(round * 16) + 9]; state[5] = g_rsbox[state[1]] ^ expanded_key[(round * 16) + 5]; state[1] = buf1; /* Row 2 */ buf1 = g_rsbox[state[2]] ^ expanded_key[(round * 16) + 10]; buf2 = g_rsbox[state[6]] ^ expanded_key[(round * 16) + 14]; state[2] = g_rsbox[state[10]] ^ expanded_key[(round * 16) + 2]; state[6] = g_rsbox[state[14]] ^ expanded_key[(round * 16) + 6]; state[10] = buf1; state[14] = buf2; /* Row 3 */ buf1 = g_rsbox[state[3]] ^ expanded_key[(round * 16) + 15]; state[3] = g_rsbox[state[7]] ^ expanded_key[(round * 16) + 3]; state[7] = g_rsbox[state[11]] ^ expanded_key[(round * 16) + 7]; state[11] = g_rsbox[state[15]] ^ expanded_key[(round * 16) + 11]; state[15] = buf1; for (round = 8; round >= 0; round--) { /* barreto */ /* Col1 */ buf1 = galois_mul2(galois_mul2(state[0] ^ state[2])); buf2 = galois_mul2(galois_mul2(state[1] ^ state[3])); state[0] ^= buf1; state[1] ^= buf2; state[2] ^= buf1; state[3] ^= buf2; /* Col2 */ buf1 = galois_mul2(galois_mul2(state[4] ^ state[6])); buf2 = galois_mul2(galois_mul2(state[5] ^ state[7])); state[4] ^= buf1; state[5] ^= buf2; state[6] ^= buf1; state[7] ^= buf2; /* Col3 */ buf1 = galois_mul2(galois_mul2(state[8] ^ state[10])); buf2 = galois_mul2(galois_mul2(state[9] ^ state[11])); state[8] ^= buf1; state[9] ^= buf2; state[10] ^= buf1; state[11] ^= buf2; /* Col4 */ buf1 = galois_mul2(galois_mul2(state[12] ^ state[14])); buf2 = galois_mul2(galois_mul2(state[13] ^ state[15])); state[12] ^= buf1; state[13] ^= buf2; state[14] ^= buf1; state[15] ^= buf2; /* mixcolums */ /* Col1 */ buf1 = state[0] ^ state[1] ^ state[2] ^ state[3]; buf2 = state[0]; buf3 = state[0] ^ state[1]; buf3 = galois_mul2(buf3); state[0] = state[0] ^ buf3 ^ buf1; buf3 = state[1] ^ state[2]; buf3 = galois_mul2(buf3); state[1] = state[1] ^ buf3 ^ buf1; buf3 = state[2] ^ state[3]; buf3 = galois_mul2(buf3); state[2] = state[2] ^ buf3 ^ buf1; buf3 = state[3] ^ buf2; buf3 = galois_mul2(buf3); state[3] = state[3] ^ buf3 ^ buf1; /* Col2 */ buf1 = state[4] ^ state[5] ^ state[6] ^ state[7]; buf2 = state[4]; buf3 = state[4] ^ state[5]; buf3 = galois_mul2(buf3); state[4] = state[4] ^ buf3 ^ buf1; buf3 = state[5] ^ state[6]; buf3 = galois_mul2(buf3); state[5] = state[5] ^ buf3 ^ buf1; buf3 = state[6] ^ state[7]; buf3 = galois_mul2(buf3); state[6] = state[6] ^ buf3 ^ buf1; buf3 = state[7] ^ buf2; buf3 = galois_mul2(buf3); state[7] = state[7] ^ buf3 ^ buf1; /* Col3 */ buf1 = state[8] ^ state[9] ^ state[10] ^ state[11]; buf2 = state[8]; buf3 = state[8] ^ state[9]; buf3 = galois_mul2(buf3); state[8] = state[8] ^ buf3 ^ buf1; buf3 = state[9] ^ state[10]; buf3 = galois_mul2(buf3); state[9] = state[9] ^ buf3 ^ buf1; buf3 = state[10] ^ state[11]; buf3 = galois_mul2(buf3); state[10] = state[10] ^ buf3 ^ buf1; buf3 = state[11] ^ buf2; buf3 = galois_mul2(buf3); state[11] = state[11] ^ buf3 ^ buf1; /* Col4 */ buf1 = state[12] ^ state[13] ^ state[14] ^ state[15]; buf2 = state[12]; buf3 = state[12] ^ state[13]; buf3 = galois_mul2(buf3); state[12] = state[12] ^ buf3 ^ buf1; buf3 = state[13] ^ state[14]; buf3 = galois_mul2(buf3); state[13] = state[13] ^ buf3 ^ buf1; buf3 = state[14] ^ state[15]; buf3 = galois_mul2(buf3); state[14] = state[14] ^ buf3 ^ buf1; buf3 = state[15] ^ buf2; buf3 = galois_mul2(buf3); state[15] = state[15] ^ buf3 ^ buf1; /* addroundkey, rsbox and shiftrows */ /* Row 0 */ state[0] = g_rsbox[state[0]] ^ expanded_key[(round * 16)]; state[4] = g_rsbox[state[4]] ^ expanded_key[(round * 16) + 4]; state[8] = g_rsbox[state[8]] ^ expanded_key[(round * 16) + 8]; state[12] = g_rsbox[state[12]] ^ expanded_key[(round * 16) + 12]; /* Row 1 */ buf1 = g_rsbox[state[13]] ^ expanded_key[(round * 16) + 1]; state[13] = g_rsbox[state[9]] ^ expanded_key[(round * 16) + 13]; state[9] = g_rsbox[state[5]] ^ expanded_key[(round * 16) + 9]; state[5] = g_rsbox[state[1]] ^ expanded_key[(round * 16) + 5]; state[1] = buf1; /* Row 2 */ buf1 = g_rsbox[state[2]] ^ expanded_key[(round * 16) + 10]; buf2 = g_rsbox[state[6]] ^ expanded_key[(round * 16) + 14]; state[2] = g_rsbox[state[10]] ^ expanded_key[(round * 16) + 2]; state[6] = g_rsbox[state[14]] ^ expanded_key[(round * 16) + 6]; state[10] = buf1; state[14] = buf2; /* Row 3 */ buf1 = g_rsbox[state[3]] ^ expanded_key[(round * 16) + 15]; state[3] = g_rsbox[state[7]] ^ expanded_key[(round * 16) + 3]; state[7] = g_rsbox[state[11]] ^ expanded_key[(round * 16) + 7]; state[11] = g_rsbox[state[15]] ^ expanded_key[(round * 16) + 11]; state[15] = buf1; } } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: aes_setupkey * * Description: * Configure the given AES context for operation with the selected key. * * Input Parameters: * state an AES context that can be used for AES operations * key a pointer to a 16-byte buffer holding the AES-128 key * len length of the key, must be 16 * * TODO: Support other key lengths of 24 (AES-192) and 32 (AES-256) * * Returned Value: * 0 if OK * -EINVAL if len is not 16 * ****************************************************************************/ int aes_setupkey(FAR struct aes_state_s *state, FAR const uint8_t *key, int len) { if (len != 16) { return -EINVAL; } expand_key(state->expanded_key, key); return 0; } /**************************************************************************** * Name: aes_encipher * * Description: * Encipher some 16-byte blocks (without any operation mode) using the * previously defined key. The function can be called multiple times with * the same state parameter. * * Returned Value: * None * ****************************************************************************/ void aes_encipher(FAR struct aes_state_s *state, FAR uint8_t *blocks, int nblk) { int i; uint32_t off = 0; for (i = 0; i < nblk; i++) { aes_encr(blocks + off, state->expanded_key); off += 16; } } /**************************************************************************** * Name: aes_decipher * * Description: * Decipher some 16-byte blocks (without any operation mode) using the * previously defined key. The function can be called multiple times with * the same state parameter. * * Returned Value: * None * ****************************************************************************/ void aes_decipher(FAR struct aes_state_s *state, FAR uint8_t *blocks, int nblk) { int i; uint32_t off = 0; for (i = 0; i < nblk; i++) { aes_decr(blocks + off, state->expanded_key); off += 16; } } /**************************************************************************** * Name: aes_encrypt * * Description: * AES128 encryption: Given AES128 key and 16 bytes plain text, cipher * text of 16 bytes is computed. The AES implementation is in mode ECB * (Electronic Code Book). * * Input Parameters: * key AES128 key of size 16 bytes * state 16 bytes of plain text and cipher text * * Returned Value: * None * ****************************************************************************/ void aes_encrypt(FAR uint8_t *state, FAR const uint8_t *key) { /* Expand the key into 176 bytes */ aes_setupkey(&g_aes_state, key, 16); aes_encr(state, g_aes_state.expanded_key); } /**************************************************************************** * Name: aes_decrypt * * Description: * AES128 decryption: Given AES128 key and 16 bytes cipher text, plain * text of 16 bytes is computed The AES implementation is in mode ECB * (Electronic Code Book). * * Input Parameters: * key AES128 key of size 16 bytes * state 16 bytes of plain text and cipher text * * Returned Value: * None * ****************************************************************************/ void aes_decrypt(FAR uint8_t *state, FAR const uint8_t *key) { /* Expand the key into 176 bytes */ aes_setupkey(&g_aes_state, key, 16); aes_decr(state, g_aes_state.expanded_key); }