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incubator-nuttx/crypto/aes.c

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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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