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- /****************************************************************************
- * 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 <nuttx/config.h>
- #include <stdint.h>
- #include <errno.h>
- #include <nuttx/crypto/aes.h>
- /****************************************************************************
- * 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);
- }
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