diff --git a/core/io/aes256.cpp b/core/io/aes256.cpp index e7f465dcc6..cfdac0214d 100644 --- a/core/io/aes256.cpp +++ b/core/io/aes256.cpp @@ -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 */