aes-internal-enc.c revision c5ec7f57ead87efa365800228aa0b09a12d9e6c4 
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 software may be distributed under the terms of the BSD license.
15 * See README for more details.
16 */
17
18#include "includes.h"
19
20#include "common.h"
21#include "crypto.h"
22#include "aes_i.h"
23
24static void rijndaelEncrypt(const u32 rk[/*44*/], const u8 pt[16], u8 ct[16])
25{
26	u32 s0, s1, s2, s3, t0, t1, t2, t3;
27	const int Nr = 10;
28#ifndef FULL_UNROLL
29	int r;
30#endif /* ?FULL_UNROLL */
31
32	/*
33	 * map byte array block to cipher state
34	 * and add initial round key:
35	 */
36	s0 = GETU32(pt     ) ^ rk[0];
37	s1 = GETU32(pt +  4) ^ rk[1];
38	s2 = GETU32(pt +  8) ^ rk[2];
39	s3 = GETU32(pt + 12) ^ rk[3];
40
41#define ROUND(i,d,s) \
42d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
43d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
44d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
45d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
46
47#ifdef FULL_UNROLL
48
49	ROUND(1,t,s);
50	ROUND(2,s,t);
51	ROUND(3,t,s);
52	ROUND(4,s,t);
53	ROUND(5,t,s);
54	ROUND(6,s,t);
55	ROUND(7,t,s);
56	ROUND(8,s,t);
57	ROUND(9,t,s);
58
59	rk += Nr << 2;
60
61#else  /* !FULL_UNROLL */
62
63	/* Nr - 1 full rounds: */
64	r = Nr >> 1;
65	for (;;) {
66		ROUND(1,t,s);
67		rk += 8;
68		if (--r == 0)
69			break;
70		ROUND(0,s,t);
71	}
72
73#endif /* ?FULL_UNROLL */
74
75#undef ROUND
76
77	/*
78	 * apply last round and
79	 * map cipher state to byte array block:
80	 */
81	s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
82	PUTU32(ct     , s0);
83	s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
84	PUTU32(ct +  4, s1);
85	s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
86	PUTU32(ct +  8, s2);
87	s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
88	PUTU32(ct + 12, s3);
89}
90
91
92void * aes_encrypt_init(const u8 *key, size_t len)
93{
94	u32 *rk;
95	if (len != 16)
96		return NULL;
97	rk = os_malloc(AES_PRIV_SIZE);
98	if (rk == NULL)
99		return NULL;
100	rijndaelKeySetupEnc(rk, key);
101	return rk;
102}
103
104
105void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
106{
107	rijndaelEncrypt(ctx, plain, crypt);
108}
109
110
111void aes_encrypt_deinit(void *ctx)
112{
113	os_memset(ctx, 0, AES_PRIV_SIZE);
114	os_free(ctx);
115}
116