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 
30 void 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) \
48 d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
49 d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
50 d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
51 d##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 
98 void * 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 
111 void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
112 {
113 	rijndaelEncrypt(ctx, plain, crypt);
114 }
115 
116 
117 void aes_encrypt_deinit(void *ctx)
118 {
119 	os_memset(ctx, 0, AES_PRIV_SIZE);
120 	os_free(ctx);
121 }
122