aes-internal-enc.c revision 8d520ff1dc2da35cdca849e982051b86468016d8 
1/*
2 * AES (Rijndael) cipher - encrypt
3 *
4 * Modifications to public domain implementation:
5 * - support only 128-bit keys
6 * - cleanup
7 * - use C pre-processor to make it easier to change S table access
8 * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
9 *   cost of reduced throughput (quite small difference on Pentium 4,
10 *   10-25% when using -O1 or -O2 optimization)
11 *
12 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 *
18 * Alternatively, this software may be distributed under the terms of BSD
19 * license.
20 *
21 * See README and COPYING for more details.
22 */
23
24#include "includes.h"
25
26#include "common.h"
27#include "crypto.h"
28#include "aes_i.h"
29
30void rijndaelEncrypt(const u32 rk[/*44*/], const u8 pt[16], u8 ct[16])
31{
32	u32 s0, s1, s2, s3, t0, t1, t2, t3;
33	const int Nr = 10;
34#ifndef FULL_UNROLL
35	int r;
36#endif /* ?FULL_UNROLL */
37
38	/*
39	 * map byte array block to cipher state
40	 * and add initial round key:
41	 */
42	s0 = GETU32(pt     ) ^ rk[0];
43	s1 = GETU32(pt +  4) ^ rk[1];
44	s2 = GETU32(pt +  8) ^ rk[2];
45	s3 = GETU32(pt + 12) ^ rk[3];
46
47#define ROUND(i,d,s) \
48d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
49d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
50d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
51d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
52
53#ifdef FULL_UNROLL
54
55	ROUND(1,t,s);
56	ROUND(2,s,t);
57	ROUND(3,t,s);
58	ROUND(4,s,t);
59	ROUND(5,t,s);
60	ROUND(6,s,t);
61	ROUND(7,t,s);
62	ROUND(8,s,t);
63	ROUND(9,t,s);
64
65	rk += Nr << 2;
66
67#else  /* !FULL_UNROLL */
68
69	/* Nr - 1 full rounds: */
70	r = Nr >> 1;
71	for (;;) {
72		ROUND(1,t,s);
73		rk += 8;
74		if (--r == 0)
75			break;
76		ROUND(0,s,t);
77	}
78
79#endif /* ?FULL_UNROLL */
80
81#undef ROUND
82
83	/*
84	 * apply last round and
85	 * map cipher state to byte array block:
86	 */
87	s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
88	PUTU32(ct     , s0);
89	s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
90	PUTU32(ct +  4, s1);
91	s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
92	PUTU32(ct +  8, s2);
93	s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
94	PUTU32(ct + 12, s3);
95}
96
97
98void * aes_encrypt_init(const u8 *key, size_t len)
99{
100	u32 *rk;
101	if (len != 16)
102		return NULL;
103	rk = os_malloc(AES_PRIV_SIZE);
104	if (rk == NULL)
105		return NULL;
106	rijndaelKeySetupEnc(rk, key);
107	return rk;
108}
109
110
111void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
112{
113	rijndaelEncrypt(ctx, plain, crypt);
114}
115
116
117void aes_encrypt_deinit(void *ctx)
118{
119	os_memset(ctx, 0, AES_PRIV_SIZE);
120	os_free(ctx);
121}
122