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Merge pull request #3022 from romulox-x/aes256

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Updated aes256 implementation
This commit is contained in:
Juan Linietsky 2015-12-08 21:16:32 -03:00
commit f86477ce93
1 changed files with 105 additions and 65 deletions
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170
core/io/aes256.cpp
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@ -1,8 +1,8 @@
/*
/*
* Byte-oriented AES-256 implementation.
* All lookup tables replaced with 'on the fly' calculations.
* All lookup tables replaced with 'on the fly' calculations.
*
* Copyright (c) 2007-2009 Ilya O. Levin, http://www.literatecode.com
* Copyright (c) 2007-2011 Ilya O. Levin, http://www.literatecode.com
* Other contributors: Hal Finney
*
* Permission to use, copy, modify, and distribute this software for any
@ -19,13 +19,33 @@
*/
#include "aes256.h"
#define F(x) (((x)<<1) ^ ((((x)>>7) & 1) * 0x1b))
#define FD(x) (((x) >> 1) ^ (((x) & 1) ? 0x8d : 0))
// #define BACK_TO_TABLES
#define BACK_TO_TABLES
static uint8_t rj_xtime(uint8_t);
static void aes_subBytes(uint8_t *);
static void aes_subBytes_inv(uint8_t *);
static void aes_addRoundKey(uint8_t *, uint8_t *);
static void aes_addRoundKey_cpy(uint8_t *, uint8_t *, uint8_t *);
static void aes_shiftRows(uint8_t *);
static void aes_shiftRows_inv(uint8_t *);
static void aes_mixColumns(uint8_t *);
static void aes_mixColumns_inv(uint8_t *);
static void aes_expandEncKey(uint8_t *, uint8_t *);
static void aes_expandDecKey(uint8_t *, uint8_t *);
#ifndef BACK_TO_TABLES
static uint8_t gf_alog(uint8_t);
static uint8_t gf_log(uint8_t);
static uint8_t gf_mulinv(uint8_t);
static uint8_t rj_sbox(uint8_t);
static uint8_t rj_sbox_inv(uint8_t);
#endif
#ifdef BACK_TO_TABLES
const uint8_t sbox[256] = {
static const uint8_t sbox[256] =
{
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
@ -59,7 +79,8 @@ const uint8_t sbox[256] = {
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
};
const uint8_t sboxinv[256] = {
static const uint8_t sboxinv[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,
@ -100,55 +121,62 @@ const uint8_t sboxinv[256] = {
#else /* tableless subroutines */
/* -------------------------------------------------------------------------- */
uint8_t gf_alog(uint8_t x) // calculate anti-logarithm gen 3
static uint8_t gf_alog(uint8_t x) // calculate anti-logarithm gen 3
{
uint8_t atb = 1, z;
uint8_t y = 1, i;
while (x--) {z = atb; atb <<= 1; if (z & 0x80) atb^= 0x1b; atb ^= z;}
for (i = 0; i < x; i++) y ^= rj_xtime(y);
return atb;
return y;
} /* gf_alog */
/* -------------------------------------------------------------------------- */
uint8_t gf_log(uint8_t x) // calculate logarithm gen 3
static uint8_t gf_log(uint8_t x) // calculate logarithm gen 3
{
uint8_t atb = 1, i = 0, z;
uint8_t y, i = 0;
do {
if (atb == x) break;
z = atb; atb <<= 1; if (z & 0x80) atb^= 0x1b; atb ^= z;
} while (++i > 0);
if (x)
for (i = 1, y = 1; i > 0; i++ )
{
y ^= rj_xtime(y);
if (y == x) break;
}
return i;
} /* gf_log */
/* -------------------------------------------------------------------------- */
uint8_t gf_mulinv(uint8_t x) // calculate multiplicative inverse
static uint8_t gf_mulinv(uint8_t x) // calculate multiplicative inverse
{
return (x) ? gf_alog(255 - gf_log(x)) : 0;
} /* gf_mulinv */
/* -------------------------------------------------------------------------- */
uint8_t rj_sbox(uint8_t x)
static uint8_t rj_sbox(uint8_t x)
{
uint8_t y, sb;
sb = y = gf_mulinv(x);
y = (y<<1)|(y>>7); sb ^= y; y = (y<<1)|(y>>7); sb ^= y;
y = (y<<1)|(y>>7); sb ^= y; y = (y<<1)|(y>>7); sb ^= y;
y = (uint8_t)(y << 1) | (y >> 7), sb ^= y;
y = (uint8_t)(y << 1) | (y >> 7), sb ^= y;
y = (uint8_t)(y << 1) | (y >> 7), sb ^= y;
y = (uint8_t)(y << 1) | (y >> 7), sb ^= y;
return (sb ^ 0x63);
} /* rj_sbox */
/* -------------------------------------------------------------------------- */
uint8_t rj_sbox_inv(uint8_t x)
static uint8_t rj_sbox_inv(uint8_t x)
{
uint8_t y, sb;
y = x ^ 0x63;
sb = y = (y<<1)|(y>>7);
y = (y<<2)|(y>>6); sb ^= y; y = (y<<3)|(y>>5); sb ^= y;
sb = y = (uint8_t)(y << 1) | (y >> 7);
y = (uint8_t)(y << 2) | (y >> 6);
sb ^= y;
y = (uint8_t)(y << 3) | (y >> 5);
sb ^= y;
return gf_mulinv(sb);
} /* rj_sbox_inv */
@ -156,13 +184,14 @@ uint8_t rj_sbox_inv(uint8_t x)
#endif
/* -------------------------------------------------------------------------- */
uint8_t rj_xtime(uint8_t x)
static uint8_t rj_xtime(uint8_t x)
{
return (x & 0x80) ? ((x << 1) ^ 0x1b) : (x << 1);
uint8_t y = (uint8_t)(x << 1);
return (x & 0x80) ? (y ^ 0x1b) : y;
} /* rj_xtime */
/* -------------------------------------------------------------------------- */
void aes_subBytes(uint8_t *buf)
static void aes_subBytes(uint8_t *buf)
{
register uint8_t i = 16;
@ -170,7 +199,7 @@ void aes_subBytes(uint8_t *buf)
} /* aes_subBytes */
/* -------------------------------------------------------------------------- */
void aes_subBytes_inv(uint8_t *buf)
static void aes_subBytes_inv(uint8_t *buf)
{
register uint8_t i = 16;
@ -178,7 +207,7 @@ void aes_subBytes_inv(uint8_t *buf)
} /* aes_subBytes_inv */
/* -------------------------------------------------------------------------- */
void aes_addRoundKey(uint8_t *buf, uint8_t *key)
static void aes_addRoundKey(uint8_t *buf, uint8_t *key)
{
register uint8_t i = 16;
@ -186,49 +215,54 @@ void aes_addRoundKey(uint8_t *buf, uint8_t *key)
} /* aes_addRoundKey */
/* -------------------------------------------------------------------------- */
void aes_addRoundKey_cpy(uint8_t *buf, uint8_t *key, uint8_t *cpk)
static void aes_addRoundKey_cpy(uint8_t *buf, uint8_t *key, uint8_t *cpk)
{
register uint8_t i = 16;
while (i--) buf[i] ^= (cpk[i] = key[i]), cpk[16+i] = key[16 + i];
while (i--) buf[i] ^= (cpk[i] = key[i]), cpk[16 + i] = key[16 + i];
} /* aes_addRoundKey_cpy */
/* -------------------------------------------------------------------------- */
void aes_shiftRows(uint8_t *buf)
static void aes_shiftRows(uint8_t *buf)
{
register uint8_t i, j; /* to make it potentially parallelable :) */
i = buf[1]; buf[1] = buf[5]; buf[5] = buf[9]; buf[9] = buf[13]; buf[13] = i;
i = buf[10]; buf[10] = buf[2]; buf[2] = i;
j = buf[3]; buf[3] = buf[15]; buf[15] = buf[11]; buf[11] = buf[7]; buf[7] = j;
j = buf[14]; buf[14] = buf[6]; buf[6] = j;
i = buf[1], buf[1] = buf[5], buf[5] = buf[9], buf[9] = buf[13], buf[13] = i;
i = buf[10], buf[10] = buf[2], buf[2] = i;
j = buf[3], buf[3] = buf[15], buf[15] = buf[11], buf[11] = buf[7], buf[7] = j;
j = buf[14], buf[14] = buf[6], buf[6] = j;
} /* aes_shiftRows */
/* -------------------------------------------------------------------------- */
void aes_shiftRows_inv(uint8_t *buf)
static void aes_shiftRows_inv(uint8_t *buf)
{
register uint8_t i, j; /* same as above :) */
i = buf[1]; buf[1] = buf[13]; buf[13] = buf[9]; buf[9] = buf[5]; buf[5] = i;
i = buf[2]; buf[2] = buf[10]; buf[10] = i;
j = buf[3]; buf[3] = buf[7]; buf[7] = buf[11]; buf[11] = buf[15]; buf[15] = j;
j = buf[6]; buf[6] = buf[14]; buf[14] = j;
i = buf[1], buf[1] = buf[13], buf[13] = buf[9], buf[9] = buf[5], buf[5] = i;
i = buf[2], buf[2] = buf[10], buf[10] = i;
j = buf[3], buf[3] = buf[7], buf[7] = buf[11], buf[11] = buf[15], buf[15] = j;
j = buf[6], buf[6] = buf[14], buf[14] = j;
} /* aes_shiftRows_inv */
/* -------------------------------------------------------------------------- */
void aes_mixColumns(uint8_t *buf)
static void aes_mixColumns(uint8_t *buf)
{
register uint8_t i, a, b, c, d, e;
for (i = 0; i < 16; i += 4)
{
a = buf[i]; b = buf[i + 1]; c = buf[i + 2]; d = buf[i + 3];
a = buf[i];
b = buf[i + 1];
c = buf[i + 2];
d = buf[i + 3];
e = a ^ b ^ c ^ d;
buf[i] ^= e ^ rj_xtime(a^b); buf[i+1] ^= e ^ rj_xtime(b^c);
buf[i+2] ^= e ^ rj_xtime(c^d); buf[i+3] ^= e ^ rj_xtime(d^a);
buf[i] ^= e ^ rj_xtime(a ^ b);
buf[i + 1] ^= e ^ rj_xtime(b ^ c);
buf[i + 2] ^= e ^ rj_xtime(c ^ d);
buf[i + 3] ^= e ^ rj_xtime(d ^ a);
}
} /* aes_mixColumns */
@ -239,17 +273,23 @@ void aes_mixColumns_inv(uint8_t *buf)
for (i = 0; i < 16; i += 4)
{
a = buf[i]; b = buf[i + 1]; c = buf[i + 2]; d = buf[i + 3];
a = buf[i];
b = buf[i + 1];
c = buf[i + 2];
d = buf[i + 3];
e = a ^ b ^ c ^ d;
z = rj_xtime(e);
x = e ^ rj_xtime(rj_xtime(z^a^c)); y = e ^ rj_xtime(rj_xtime(z^b^d));
buf[i] ^= x ^ rj_xtime(a^b); buf[i+1] ^= y ^ rj_xtime(b^c);
buf[i+2] ^= x ^ rj_xtime(c^d); buf[i+3] ^= y ^ rj_xtime(d^a);
x = e ^ rj_xtime(rj_xtime(z ^ a ^ c));
y = e ^ rj_xtime(rj_xtime(z ^ b ^ d));
buf[i] ^= x ^ rj_xtime(a ^ b);
buf[i + 1] ^= y ^ rj_xtime(b ^ c);
buf[i + 2] ^= x ^ rj_xtime(c ^ d);
buf[i + 3] ^= y ^ rj_xtime(d ^ a);
}
} /* aes_mixColumns_inv */
/* -------------------------------------------------------------------------- */
void aes_expandEncKey(uint8_t *k, uint8_t *rc)
static void aes_expandEncKey(uint8_t *k, uint8_t *rc)
{
register uint8_t i;
@ -257,35 +297,35 @@ void aes_expandEncKey(uint8_t *k, uint8_t *rc)
k[1] ^= rj_sbox(k[30]);
k[2] ^= rj_sbox(k[31]);
k[3] ^= rj_sbox(k[28]);
*rc = F( *rc);
*rc = rj_xtime( *rc);
for(i = 4; i < 16; i += 4) k[i] ^= k[i-4], k[i+1] ^= k[i-3],
k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];
for(i = 4; i < 16; i += 4) k[i] ^= k[i - 4], k[i + 1] ^= k[i - 3],
k[i + 2] ^= k[i - 2], k[i + 3] ^= k[i - 1];
k[16] ^= rj_sbox(k[12]);
k[17] ^= rj_sbox(k[13]);
k[18] ^= rj_sbox(k[14]);
k[19] ^= rj_sbox(k[15]);
for(i = 20; i < 32; i += 4) k[i] ^= k[i-4], k[i+1] ^= k[i-3],
k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];
for(i = 20; i < 32; i += 4) k[i] ^= k[i - 4], k[i + 1] ^= k[i - 3],
k[i + 2] ^= k[i - 2], k[i + 3] ^= k[i - 1];
} /* aes_expandEncKey */
/* -------------------------------------------------------------------------- */
void aes_expandDecKey(uint8_t *k, uint8_t *rc)
void aes_expandDecKey(uint8_t *k, uint8_t *rc)
{
uint8_t i;
for(i = 28; i > 16; i -= 4) k[i+0] ^= k[i-4], k[i+1] ^= k[i-3],
k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];
for(i = 28; i > 16; i -= 4) k[i + 0] ^= k[i - 4], k[i + 1] ^= k[i - 3],
k[i + 2] ^= k[i - 2], k[i + 3] ^= k[i - 1];
k[16] ^= rj_sbox(k[12]);
k[17] ^= rj_sbox(k[13]);
k[18] ^= rj_sbox(k[14]);
k[19] ^= rj_sbox(k[15]);
for(i = 12; i > 0; i -= 4) k[i+0] ^= k[i-4], k[i+1] ^= k[i-3],
k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];
for(i = 12; i > 0; i -= 4) k[i + 0] ^= k[i - 4], k[i + 1] ^= k[i - 3],
k[i + 2] ^= k[i - 2], k[i + 3] ^= k[i - 1];
*rc = FD(*rc);
k[0] ^= rj_sbox(k[29]) ^ (*rc);
@ -302,7 +342,7 @@ void aes256_init(aes256_context *ctx, uint8_t *k)
register uint8_t i;
for (i = 0; i < sizeof(ctx->key); i++) ctx->enckey[i] = ctx->deckey[i] = k[i];
for (i = 8;--i;) aes_expandEncKey(ctx->deckey, &rcon);
for (i = 8; --i;) aes_expandEncKey(ctx->deckey, &rcon);
} /* aes256_init */
/* -------------------------------------------------------------------------- */
@ -310,7 +350,7 @@ void aes256_done(aes256_context *ctx)
{
register uint8_t i;
for (i = 0; i < sizeof(ctx->key); i++)
for (i = 0; i < sizeof(ctx->key); i++)
ctx->key[i] = ctx->enckey[i] = ctx->deckey[i] = 0;
} /* aes256_done */
@ -330,7 +370,7 @@ void aes256_encrypt_ecb(aes256_context *ctx, uint8_t *buf)
}
aes_subBytes(buf);
aes_shiftRows(buf);
aes_expandEncKey(ctx->key, &rcon);
aes_expandEncKey(ctx->key, &rcon);
aes_addRoundKey(buf, ctx->key);
} /* aes256_encrypt */
@ -345,7 +385,7 @@ void aes256_decrypt_ecb(aes256_context *ctx, uint8_t *buf)
for (i = 14, rcon = 0x80; --i;)
{
if( ( i & 1 ) )
if( ( i & 1 ) )
{
aes_expandDecKey(ctx->key, &rcon);
aes_addRoundKey(buf, &ctx->key[16]);
@ -355,5 +395,5 @@ void aes256_decrypt_ecb(aes256_context *ctx, uint8_t *buf)
aes_shiftRows_inv(buf);
aes_subBytes_inv(buf);
}
aes_addRoundKey( buf, ctx->key);
aes_addRoundKey( buf, ctx->key);
} /* aes256_decrypt */