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 "rtw_crypto_wrap.h"
18
19 #include "aes_i.h"
20
rijndaelEncrypt(const u32 rk[],int Nr,const u8 pt[16],u8 ct[16])21 static void rijndaelEncrypt(const u32 rk[], int Nr, const u8 pt[16], u8 ct[16])
22 {
23 u32 s0, s1, s2, s3, t0, t1, t2, t3;
24 #ifndef FULL_UNROLL
25 int r;
26 #endif /* ?FULL_UNROLL */
27
28 /*
29 * map byte array block to cipher state
30 * and add initial round key:
31 */
32 s0 = GETU32(pt ) ^ rk[0];
33 s1 = GETU32(pt + 4) ^ rk[1];
34 s2 = GETU32(pt + 8) ^ rk[2];
35 s3 = GETU32(pt + 12) ^ rk[3];
36
37 #define ROUND(i,d,s) \
38 d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
39 d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
40 d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
41 d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
42
43 #ifdef FULL_UNROLL
44
45 ROUND(1,t,s);
46 ROUND(2,s,t);
47 ROUND(3,t,s);
48 ROUND(4,s,t);
49 ROUND(5,t,s);
50 ROUND(6,s,t);
51 ROUND(7,t,s);
52 ROUND(8,s,t);
53 ROUND(9,t,s);
54 if (Nr > 10) {
55 ROUND(10,s,t);
56 ROUND(11,t,s);
57 if (Nr > 12) {
58 ROUND(12,s,t);
59 ROUND(13,t,s);
60 }
61 }
62
63 rk += Nr << 2;
64
65 #else /* !FULL_UNROLL */
66
67 /* Nr - 1 full rounds: */
68 r = Nr >> 1;
69 for (;;) {
70 ROUND(1,t,s);
71 rk += 8;
72 if (--r == 0)
73 break;
74 ROUND(0,s,t);
75 }
76
77 #endif /* ?FULL_UNROLL */
78
79 #undef ROUND
80
81 /*
82 * apply last round and
83 * map cipher state to byte array block:
84 */
85 s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
86 PUTU32(ct , s0);
87 s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
88 PUTU32(ct + 4, s1);
89 s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
90 PUTU32(ct + 8, s2);
91 s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
92 PUTU32(ct + 12, s3);
93 }
94
95
aes_encrypt_init(const u8 * key,size_t len)96 void * aes_encrypt_init(const u8 *key, size_t len)
97 {
98 u32 *rk;
99 int res;
100
101 if (TEST_FAIL())
102 return NULL;
103
104 rk = os_malloc(AES_PRIV_SIZE);
105 if (rk == NULL)
106 return NULL;
107 res = rijndaelKeySetupEnc(rk, key, len * 8);
108 if (res < 0) {
109 rtw_mfree(rk, AES_PRIV_SIZE);
110 return NULL;
111 }
112 rk[AES_PRIV_NR_POS] = res;
113 return rk;
114 }
115
116
aes_encrypt(void * ctx,const u8 * plain,u8 * crypt)117 int aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
118 {
119 u32 *rk = ctx;
120 rijndaelEncrypt(ctx, rk[AES_PRIV_NR_POS], plain, crypt);
121 return 0;
122 }
123
124
aes_encrypt_deinit(void * ctx)125 void aes_encrypt_deinit(void *ctx)
126 {
127 os_memset(ctx, 0, AES_PRIV_SIZE);
128 rtw_mfree(ctx, AES_PRIV_SIZE);
129 }
130