aes-internal-enc.c revision 9bce59c7fef20e34a05f04d1e33a4076083dca0c 
1/*
2 * AES (Rijndael) cipher - encrypt
3 *
4 * Modifications to public domain implementation:
5 * - cleanup
6 * - use C pre-processor to make it easier to change S table access
7 * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
8 *   cost of reduced throughput (quite small difference on Pentium 4,
9 *   10-25% when using -O1 or -O2 optimization)
10 *
11 * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
12 *
13 * This software may be distributed under the terms of the BSD license.
14 * See README for more details.
15 */
16
17#include "includes.h"
18
19#include "common.h"
20#include "crypto.h"
21#include "aes_i.h"
22
23static void rijndaelEncrypt(const u32 rk[], int Nr, const u8 pt[16], u8 ct[16])
24{
25	u32 s0, s1, s2, s3, t0, t1, t2, t3;
26#ifndef FULL_UNROLL
27	int r;
28#endif /* ?FULL_UNROLL */
29
30	/*
31	 * map byte array block to cipher state
32	 * and add initial round key:
33	 */
34	s0 = GETU32(pt     ) ^ rk[0];
35	s1 = GETU32(pt +  4) ^ rk[1];
36	s2 = GETU32(pt +  8) ^ rk[2];
37	s3 = GETU32(pt + 12) ^ rk[3];
38
39#define ROUND(i,d,s) \
40d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
41d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
42d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
43d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
44
45#ifdef FULL_UNROLL
46
47	ROUND(1,t,s);
48	ROUND(2,s,t);
49	ROUND(3,t,s);
50	ROUND(4,s,t);
51	ROUND(5,t,s);
52	ROUND(6,s,t);
53	ROUND(7,t,s);
54	ROUND(8,s,t);
55	ROUND(9,t,s);
56	if (Nr > 10) {
57		ROUND(10,s,t);
58		ROUND(11,t,s);
59		if (Nr > 12) {
60			ROUND(12,s,t);
61			ROUND(13,t,s);
62		}
63	}
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	int res;
102	rk = os_malloc(AES_PRIV_SIZE);
103	if (rk == NULL)
104		return NULL;
105	res = rijndaelKeySetupEnc(rk, key, len * 8);
106	if (res < 0) {
107		os_free(rk);
108		return NULL;
109	}
110	rk[AES_PRIV_NR_POS] = res;
111	return rk;
112}
113
114
115void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
116{
117	u32 *rk = ctx;
118	rijndaelEncrypt(ctx, rk[AES_PRIV_NR_POS], plain, crypt);
119}
120
121
122void aes_encrypt_deinit(void *ctx)
123{
124	os_memset(ctx, 0, AES_PRIV_SIZE);
125	os_free(ctx);
126}
127