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 
23 static 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) \
40 d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
41 d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
42 d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
43 d##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 
98 void * 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 
115 void 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 
122 void aes_encrypt_deinit(void *ctx)
123 {
124 	os_memset(ctx, 0, AES_PRIV_SIZE);
125 	os_free(ctx);
126 }
127