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/*
-------------------------------------------------------------------------
Copyright (c) 2001, Dr Brian Gladman <brg@gladman.uk.net>, Worcester, UK.
All rights reserved.
LICENSE TERMS
The free distribution and use of this software in both source and binary
form is allowed (with or without changes) provided that:
1. distributions of this source code include the above copyright
notice, this list of conditions and the following disclaimer;
2. distributions in binary form include the above copyright
notice, this list of conditions and the following disclaimer
in the documentation and/or other associated materials;
3. the copyright holder's name is not used to endorse products
built using this software without specific written permission.
DISCLAIMER
This software is provided 'as is' with no explcit or implied warranties
in respect of any properties, including, but not limited to, correctness
and fitness for purpose.
-------------------------------------------------------------------------
Issue Date: 21/01/2002
This file contains the code for implementing the key schedule for AES
(Rijndael) for block and key sizes of 16, 24, and 32 bytes.
*/
#include "aesopt.h"
#if defined(BLOCK_SIZE) && (BLOCK_SIZE & 7)
#error An illegal block size has been specified.
#endif
/* Subroutine to set the block size (if variable) in bytes, legal
values being 16, 24 and 32.
*/
#if !defined(BLOCK_SIZE) && defined(SET_BLOCK_LENGTH)
aes_rval aes_blk_len(unsigned int blen, aes_ctx cx[1])
{
#if !defined(FIXED_TABLES)
if(!tab_init) gen_tabs();
#endif
if((blen & 7) || blen < 16 || blen > 32)
{
cx->n_blk = 0; return aes_bad;
}
cx->n_blk = blen;
return aes_good;
}
#endif
/* Initialise the key schedule from the user supplied key. The key
length is now specified in bytes - 16, 24 or 32 as appropriate.
This corresponds to bit lengths of 128, 192 and 256 bits, and
to Nk values of 4, 6 and 8 respectively.
The following macros implement a single cycle in the key
schedule generation process. The number of cycles needed
for each cx->n_col and nk value is:
nk = 4 5 6 7 8
------------------------------
cx->n_col = 4 10 9 8 7 7
cx->n_col = 5 14 11 10 9 9
cx->n_col = 6 19 15 12 11 11
cx->n_col = 7 21 19 16 13 14
cx->n_col = 8 29 23 19 17 14
*/
#if defined(ENCRYPTION_KEY_SCHEDULE)
#define ke4(k,i) \
{ k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; k[4*(i)+5] = ss[1] ^= ss[0]; \
k[4*(i)+6] = ss[2] ^= ss[1]; k[4*(i)+7] = ss[3] ^= ss[2]; \
}
#define kel4(k,i) \
{ k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; k[4*(i)+5] = ss[1] ^= ss[0]; \
k[4*(i)+6] = ss[2] ^= ss[1]; k[4*(i)+7] = ss[3] ^= ss[2]; \
}
#define ke6(k,i) \
{ k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; k[6*(i)+ 7] = ss[1] ^= ss[0]; \
k[6*(i)+ 8] = ss[2] ^= ss[1]; k[6*(i)+ 9] = ss[3] ^= ss[2]; \
k[6*(i)+10] = ss[4] ^= ss[3]; k[6*(i)+11] = ss[5] ^= ss[4]; \
}
#define kel6(k,i) \
{ k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; k[6*(i)+ 7] = ss[1] ^= ss[0]; \
k[6*(i)+ 8] = ss[2] ^= ss[1]; k[6*(i)+ 9] = ss[3] ^= ss[2]; \
}
#define ke8(k,i) \
{ k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; k[8*(i)+ 9] = ss[1] ^= ss[0]; \
k[8*(i)+10] = ss[2] ^= ss[1]; k[8*(i)+11] = ss[3] ^= ss[2]; \
k[8*(i)+12] = ss[4] ^= ls_box(ss[3],0); k[8*(i)+13] = ss[5] ^= ss[4]; \
k[8*(i)+14] = ss[6] ^= ss[5]; k[8*(i)+15] = ss[7] ^= ss[6]; \
}
#define kel8(k,i) \
{ k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; k[8*(i)+ 9] = ss[1] ^= ss[0]; \
k[8*(i)+10] = ss[2] ^= ss[1]; k[8*(i)+11] = ss[3] ^= ss[2]; \
}
aes_rval aes_enc_key(const unsigned char in_key[], unsigned int klen, aes_ctx cx[1])
{ uint32_t ss[8];
#if !defined(FIXED_TABLES)
if(!tab_init) gen_tabs();
#endif
#if !defined(BLOCK_SIZE)
if(!cx->n_blk) cx->n_blk = 16;
#else
cx->n_blk = BLOCK_SIZE;
#endif
cx->n_blk = (cx->n_blk & ~3U) | 1;
cx->k_sch[0] = ss[0] = word_in(in_key );
cx->k_sch[1] = ss[1] = word_in(in_key + 4);
cx->k_sch[2] = ss[2] = word_in(in_key + 8);
cx->k_sch[3] = ss[3] = word_in(in_key + 12);
#if (BLOCK_SIZE == 16) && (ENC_UNROLL != NONE)
switch(klen)
{
case 16: ke4(cx->k_sch, 0); ke4(cx->k_sch, 1);
ke4(cx->k_sch, 2); ke4(cx->k_sch, 3);
ke4(cx->k_sch, 4); ke4(cx->k_sch, 5);
ke4(cx->k_sch, 6); ke4(cx->k_sch, 7);
ke4(cx->k_sch, 8); kel4(cx->k_sch, 9);
cx->n_rnd = 10; break;
case 24: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
ke6(cx->k_sch, 0); ke6(cx->k_sch, 1);
ke6(cx->k_sch, 2); ke6(cx->k_sch, 3);
ke6(cx->k_sch, 4); ke6(cx->k_sch, 5);
ke6(cx->k_sch, 6); kel6(cx->k_sch, 7);
cx->n_rnd = 12; break;
case 32: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
cx->k_sch[6] = ss[6] = word_in(in_key + 24);
cx->k_sch[7] = ss[7] = word_in(in_key + 28);
ke8(cx->k_sch, 0); ke8(cx->k_sch, 1);
ke8(cx->k_sch, 2); ke8(cx->k_sch, 3);
ke8(cx->k_sch, 4); ke8(cx->k_sch, 5);
kel8(cx->k_sch, 6);
cx->n_rnd = 14; break;
default: cx->n_rnd = 0; return aes_bad;
}
#else
{ uint32_t i, l;
cx->n_rnd = ((klen >> 2) > nc ? (klen >> 2) : nc) + 6;
l = (nc * cx->n_rnd + nc - 1) / (klen >> 2);
switch(klen)
{
case 16: for(i = 0; i < l; ++i)
ke4(cx->k_sch, i);
break;
case 24: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
for(i = 0; i < l; ++i)
ke6(cx->k_sch, i);
break;
case 32: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
cx->k_sch[6] = ss[6] = word_in(in_key + 24);
cx->k_sch[7] = ss[7] = word_in(in_key + 28);
for(i = 0; i < l; ++i)
ke8(cx->k_sch, i);
break;
default: cx->n_rnd = 0; return aes_bad;
}
}
#endif
return aes_good;
}
#endif
#if defined(DECRYPTION_KEY_SCHEDULE)
#if (DEC_ROUND != NO_TABLES)
#define d_vars dec_imvars
#define ff(x) inv_mcol(x)
#else
#define ff(x) (x)
#define d_vars
#endif
#if 1
#define kdf4(k,i) \
{ ss[0] = ss[0] ^ ss[2] ^ ss[1] ^ ss[3]; ss[1] = ss[1] ^ ss[3]; ss[2] = ss[2] ^ ss[3]; ss[3] = ss[3]; \
ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; ss[i % 4] ^= ss[4]; \
ss[4] ^= k[4*(i)]; k[4*(i)+4] = ff(ss[4]); ss[4] ^= k[4*(i)+1]; k[4*(i)+5] = ff(ss[4]); \
ss[4] ^= k[4*(i)+2]; k[4*(i)+6] = ff(ss[4]); ss[4] ^= k[4*(i)+3]; k[4*(i)+7] = ff(ss[4]); \
}
#define kd4(k,i) \
{ ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; ss[i % 4] ^= ss[4]; ss[4] = ff(ss[4]); \
k[4*(i)+4] = ss[4] ^= k[4*(i)]; k[4*(i)+5] = ss[4] ^= k[4*(i)+1]; \
k[4*(i)+6] = ss[4] ^= k[4*(i)+2]; k[4*(i)+7] = ss[4] ^= k[4*(i)+3]; \
}
#define kdl4(k,i) \
{ ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i]; ss[i % 4] ^= ss[4]; \
k[4*(i)+4] = (ss[0] ^= ss[1]) ^ ss[2] ^ ss[3]; k[4*(i)+5] = ss[1] ^ ss[3]; \
k[4*(i)+6] = ss[0]; k[4*(i)+7] = ss[1]; \
}
#else
#define kdf4(k,i) \
{ ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; k[4*(i)+ 4] = ff(ss[0]); ss[1] ^= ss[0]; k[4*(i)+ 5] = ff(ss[1]); \
ss[2] ^= ss[1]; k[4*(i)+ 6] = ff(ss[2]); ss[3] ^= ss[2]; k[4*(i)+ 7] = ff(ss[3]); \
}
#define kd4(k,i) \
{ ss[4] = ls_box(ss[3],3) ^ rcon_tab[i]; \
ss[0] ^= ss[4]; ss[4] = ff(ss[4]); k[4*(i)+ 4] = ss[4] ^= k[4*(i)]; \
ss[1] ^= ss[0]; k[4*(i)+ 5] = ss[4] ^= k[4*(i)+ 1]; \
ss[2] ^= ss[1]; k[4*(i)+ 6] = ss[4] ^= k[4*(i)+ 2]; \
ss[3] ^= ss[2]; k[4*(i)+ 7] = ss[4] ^= k[4*(i)+ 3]; \
}
#define kdl4(k,i) \
{ ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i]; k[4*(i)+ 4] = ss[0]; ss[1] ^= ss[0]; k[4*(i)+ 5] = ss[1]; \
ss[2] ^= ss[1]; k[4*(i)+ 6] = ss[2]; ss[3] ^= ss[2]; k[4*(i)+ 7] = ss[3]; \
}
#endif
#define kdf6(k,i) \
{ ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; k[6*(i)+ 6] = ff(ss[0]); ss[1] ^= ss[0]; k[6*(i)+ 7] = ff(ss[1]); \
ss[2] ^= ss[1]; k[6*(i)+ 8] = ff(ss[2]); ss[3] ^= ss[2]; k[6*(i)+ 9] = ff(ss[3]); \
ss[4] ^= ss[3]; k[6*(i)+10] = ff(ss[4]); ss[5] ^= ss[4]; k[6*(i)+11] = ff(ss[5]); \
}
#define kd6(k,i) \
{ ss[6] = ls_box(ss[5],3) ^ rcon_tab[i]; \
ss[0] ^= ss[6]; ss[6] = ff(ss[6]); k[6*(i)+ 6] = ss[6] ^= k[6*(i)]; \
ss[1] ^= ss[0]; k[6*(i)+ 7] = ss[6] ^= k[6*(i)+ 1]; \
ss[2] ^= ss[1]; k[6*(i)+ 8] = ss[6] ^= k[6*(i)+ 2]; \
ss[3] ^= ss[2]; k[6*(i)+ 9] = ss[6] ^= k[6*(i)+ 3]; \
ss[4] ^= ss[3]; k[6*(i)+10] = ss[6] ^= k[6*(i)+ 4]; \
ss[5] ^= ss[4]; k[6*(i)+11] = ss[6] ^= k[6*(i)+ 5]; \
}
#define kdl6(k,i) \
{ ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i]; k[6*(i)+ 6] = ss[0]; ss[1] ^= ss[0]; k[6*(i)+ 7] = ss[1]; \
ss[2] ^= ss[1]; k[6*(i)+ 8] = ss[2]; ss[3] ^= ss[2]; k[6*(i)+ 9] = ss[3]; \
}
#define kdf8(k,i) \
{ ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; k[8*(i)+ 8] = ff(ss[0]); ss[1] ^= ss[0]; k[8*(i)+ 9] = ff(ss[1]); \
ss[2] ^= ss[1]; k[8*(i)+10] = ff(ss[2]); ss[3] ^= ss[2]; k[8*(i)+11] = ff(ss[3]); \
ss[4] ^= ls_box(ss[3],0); k[8*(i)+12] = ff(ss[4]); ss[5] ^= ss[4]; k[8*(i)+13] = ff(ss[5]); \
ss[6] ^= ss[5]; k[8*(i)+14] = ff(ss[6]); ss[7] ^= ss[6]; k[8*(i)+15] = ff(ss[7]); \
}
#define kd8(k,i) \
{ uint32_t g = ls_box(ss[7],3) ^ rcon_tab[i]; \
ss[0] ^= g; g = ff(g); k[8*(i)+ 8] = g ^= k[8*(i)]; \
ss[1] ^= ss[0]; k[8*(i)+ 9] = g ^= k[8*(i)+ 1]; \
ss[2] ^= ss[1]; k[8*(i)+10] = g ^= k[8*(i)+ 2]; \
ss[3] ^= ss[2]; k[8*(i)+11] = g ^= k[8*(i)+ 3]; \
g = ls_box(ss[3],0); \
ss[4] ^= g; g = ff(g); k[8*(i)+12] = g ^= k[8*(i)+ 4]; \
ss[5] ^= ss[4]; k[8*(i)+13] = g ^= k[8*(i)+ 5]; \
ss[6] ^= ss[5]; k[8*(i)+14] = g ^= k[8*(i)+ 6]; \
ss[7] ^= ss[6]; k[8*(i)+15] = g ^= k[8*(i)+ 7]; \
}
#define kdl8(k,i) \
{ ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i]; k[8*(i)+ 8] = ss[0]; ss[1] ^= ss[0]; k[8*(i)+ 9] = ss[1]; \
ss[2] ^= ss[1]; k[8*(i)+10] = ss[2]; ss[3] ^= ss[2]; k[8*(i)+11] = ss[3]; \
}
aes_rval aes_dec_key(const unsigned char in_key[], unsigned int klen, aes_ctx cx[1])
{ uint32_t ss[8];
d_vars
#if !defined(FIXED_TABLES)
if(!tab_init) gen_tabs();
#endif
#if !defined(BLOCK_SIZE)
if(!cx->n_blk) cx->n_blk = 16;
#else
cx->n_blk = BLOCK_SIZE;
#endif
cx->n_blk = (cx->n_blk & ~3U) | 2;
cx->k_sch[0] = ss[0] = word_in(in_key );
cx->k_sch[1] = ss[1] = word_in(in_key + 4);
cx->k_sch[2] = ss[2] = word_in(in_key + 8);
cx->k_sch[3] = ss[3] = word_in(in_key + 12);
#if (BLOCK_SIZE == 16) && (DEC_UNROLL != NONE)
switch(klen)
{
case 16: kdf4(cx->k_sch, 0); kd4(cx->k_sch, 1);
kd4(cx->k_sch, 2); kd4(cx->k_sch, 3);
kd4(cx->k_sch, 4); kd4(cx->k_sch, 5);
kd4(cx->k_sch, 6); kd4(cx->k_sch, 7);
kd4(cx->k_sch, 8); kdl4(cx->k_sch, 9);
cx->n_rnd = 10; break;
case 24: cx->k_sch[4] = ff(ss[4] = word_in(in_key + 16));
cx->k_sch[5] = ff(ss[5] = word_in(in_key + 20));
kdf6(cx->k_sch, 0); kd6(cx->k_sch, 1);
kd6(cx->k_sch, 2); kd6(cx->k_sch, 3);
kd6(cx->k_sch, 4); kd6(cx->k_sch, 5);
kd6(cx->k_sch, 6); kdl6(cx->k_sch, 7);
cx->n_rnd = 12; break;
case 32: cx->k_sch[4] = ff(ss[4] = word_in(in_key + 16));
cx->k_sch[5] = ff(ss[5] = word_in(in_key + 20));
cx->k_sch[6] = ff(ss[6] = word_in(in_key + 24));
cx->k_sch[7] = ff(ss[7] = word_in(in_key + 28));
kdf8(cx->k_sch, 0); kd8(cx->k_sch, 1);
kd8(cx->k_sch, 2); kd8(cx->k_sch, 3);
kd8(cx->k_sch, 4); kd8(cx->k_sch, 5);
kdl8(cx->k_sch, 6);
cx->n_rnd = 14; break;
default: cx->n_rnd = 0; return aes_bad;
}
#else
{ uint32_t i, l;
cx->n_rnd = ((klen >> 2) > nc ? (klen >> 2) : nc) + 6;
l = (nc * cx->n_rnd + nc - 1) / (klen >> 2);
switch(klen)
{
case 16:
for(i = 0; i < l; ++i)
ke4(cx->k_sch, i);
break;
case 24: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
for(i = 0; i < l; ++i)
ke6(cx->k_sch, i);
break;
case 32: cx->k_sch[4] = ss[4] = word_in(in_key + 16);
cx->k_sch[5] = ss[5] = word_in(in_key + 20);
cx->k_sch[6] = ss[6] = word_in(in_key + 24);
cx->k_sch[7] = ss[7] = word_in(in_key + 28);
for(i = 0; i < l; ++i)
ke8(cx->k_sch, i);
break;
default: cx->n_rnd = 0; return aes_bad;
}
#if (DEC_ROUND != NO_TABLES)
for(i = nc; i < nc * cx->n_rnd; ++i)
cx->k_sch[i] = inv_mcol(cx->k_sch[i]);
#endif
}
#endif
return aes_good;
}
#endif
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