hostap/src/crypto/aes-internal-enc.c
Jouni Malinen d140db6adf Add support for using 192-bit and 256-bit keys with AES-GCM
This adds 192-bit and 256-bit key support to the internal AES
implementation and extends the AES-GCM functions to accept key length to
enable longer AES key use.

Signed-hostap: Jouni Malinen <j@w1.fi>
2012-09-09 13:30:51 +03:00

126 lines
2.6 KiB
C

/*
* AES (Rijndael) cipher - encrypt
*
* Modifications to public domain implementation:
* - cleanup
* - use C pre-processor to make it easier to change S table access
* - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
* cost of reduced throughput (quite small difference on Pentium 4,
* 10-25% when using -O1 or -O2 optimization)
*
* Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto.h"
#include "aes_i.h"
static void rijndaelEncrypt(const u32 rk[], int Nr, const u8 pt[16], u8 ct[16])
{
u32 s0, s1, s2, s3, t0, t1, t2, t3;
#ifndef FULL_UNROLL
int r;
#endif /* ?FULL_UNROLL */
/*
* map byte array block to cipher state
* and add initial round key:
*/
s0 = GETU32(pt ) ^ rk[0];
s1 = GETU32(pt + 4) ^ rk[1];
s2 = GETU32(pt + 8) ^ rk[2];
s3 = GETU32(pt + 12) ^ rk[3];
#define ROUND(i,d,s) \
d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
#ifdef FULL_UNROLL
ROUND(1,t,s);
ROUND(2,s,t);
ROUND(3,t,s);
ROUND(4,s,t);
ROUND(5,t,s);
ROUND(6,s,t);
ROUND(7,t,s);
ROUND(8,s,t);
ROUND(9,t,s);
if (Nr > 10) {
ROUND(10,s,t);
ROUND(11,t,s);
if (Nr > 12) {
ROUND(12,s,t);
ROUND(13,t,s);
}
}
rk += Nr << 2;
#else /* !FULL_UNROLL */
/* Nr - 1 full rounds: */
r = Nr >> 1;
for (;;) {
ROUND(1,t,s);
rk += 8;
if (--r == 0)
break;
ROUND(0,s,t);
}
#endif /* ?FULL_UNROLL */
#undef ROUND
/*
* apply last round and
* map cipher state to byte array block:
*/
s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
PUTU32(ct , s0);
s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
PUTU32(ct + 4, s1);
s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
PUTU32(ct + 8, s2);
s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
PUTU32(ct + 12, s3);
}
void * aes_encrypt_init(const u8 *key, size_t len)
{
u32 *rk;
int res;
rk = os_malloc(AES_PRIV_SIZE);
if (rk == NULL)
return NULL;
res = rijndaelKeySetupEnc(rk, key, len * 8);
if (res < 0) {
os_free(rk);
return NULL;
}
rk[AES_PRIV_NR_POS] = res;
return rk;
}
void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
{
u32 *rk = ctx;
rijndaelEncrypt(ctx, rk[AES_PRIV_NR_POS], plain, crypt);
}
void aes_encrypt_deinit(void *ctx)
{
os_memset(ctx, 0, AES_PRIV_SIZE);
os_free(ctx);
}