1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file pelican.c
15 Pelican MAC, initialize state, by Tom St Denis
16 */
17
18 #ifdef PELICAN
19
20 #define ENCRYPT_ONLY
21 #define PELI_TAB
22 #include "../../ciphers/aes/aes_tab.c"
23
24 /**
25 Initialize a Pelican state
26 @param pelmac The Pelican state to initialize
27 @param key The secret key
28 @param keylen The length of the secret key (octets)
29 @return CRYPT_OK if successful
30 */
pelican_init(pelican_state * pelmac,const unsigned char * key,unsigned long keylen)31 int pelican_init(pelican_state *pelmac, const unsigned char *key, unsigned long keylen)
32 {
33 int err;
34
35 LTC_ARGCHK(pelmac != NULL);
36 LTC_ARGCHK(key != NULL);
37
38 #ifdef LTC_FAST
39 if (16 % sizeof(LTC_FAST_TYPE)) {
40 return CRYPT_INVALID_ARG;
41 }
42 #endif
43
44 if ((err = aes_setup(key, keylen, 0, &pelmac->K)) != CRYPT_OK) {
45 return err;
46 }
47
48 zeromem(pelmac->state, 16);
49 aes_ecb_encrypt(pelmac->state, pelmac->state, &pelmac->K);
50 pelmac->buflen = 0;
51
52 return CRYPT_OK;
53 }
54
four_rounds(pelican_state * pelmac)55 static void four_rounds(pelican_state *pelmac)
56 {
57 ulong32 s0, s1, s2, s3, t0, t1, t2, t3;
58 int r;
59
60 LOAD32H(s0, pelmac->state );
61 LOAD32H(s1, pelmac->state + 4);
62 LOAD32H(s2, pelmac->state + 8);
63 LOAD32H(s3, pelmac->state + 12);
64 for (r = 0; r < 4; r++) {
65 t0 =
66 Te0(byte(s0, 3)) ^
67 Te1(byte(s1, 2)) ^
68 Te2(byte(s2, 1)) ^
69 Te3(byte(s3, 0));
70 t1 =
71 Te0(byte(s1, 3)) ^
72 Te1(byte(s2, 2)) ^
73 Te2(byte(s3, 1)) ^
74 Te3(byte(s0, 0));
75 t2 =
76 Te0(byte(s2, 3)) ^
77 Te1(byte(s3, 2)) ^
78 Te2(byte(s0, 1)) ^
79 Te3(byte(s1, 0));
80 t3 =
81 Te0(byte(s3, 3)) ^
82 Te1(byte(s0, 2)) ^
83 Te2(byte(s1, 1)) ^
84 Te3(byte(s2, 0));
85 s0 = t0; s1 = t1; s2 = t2; s3 = t3;
86 }
87 STORE32H(s0, pelmac->state );
88 STORE32H(s1, pelmac->state + 4);
89 STORE32H(s2, pelmac->state + 8);
90 STORE32H(s3, pelmac->state + 12);
91 }
92
93 /**
94 Process a block of text through Pelican
95 @param pelmac The Pelican MAC state
96 @param in The input
97 @param inlen The length input (octets)
98 @return CRYPT_OK on success
99 */
pelican_process(pelican_state * pelmac,const unsigned char * in,unsigned long inlen)100 int pelican_process(pelican_state *pelmac, const unsigned char *in, unsigned long inlen)
101 {
102
103 LTC_ARGCHK(pelmac != NULL);
104 LTC_ARGCHK(in != NULL);
105
106 /* check range */
107 if (pelmac->buflen < 0 || pelmac->buflen > 15) {
108 return CRYPT_INVALID_ARG;
109 }
110
111 #ifdef LTC_FAST
112 if (pelmac->buflen == 0) {
113 while (inlen & ~15) {
114 int x;
115 for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
116 *((LTC_FAST_TYPE*)((unsigned char *)pelmac->state + x)) ^= *((LTC_FAST_TYPE*)((unsigned char *)in + x));
117 }
118 four_rounds(pelmac);
119 in += 16;
120 inlen -= 16;
121 }
122 }
123 #endif
124
125 while (inlen--) {
126 pelmac->state[pelmac->buflen++] ^= *in++;
127 if (pelmac->buflen == 16) {
128 four_rounds(pelmac);
129 pelmac->buflen = 0;
130 }
131 }
132 return CRYPT_OK;
133 }
134
135 /**
136 Terminate Pelican MAC
137 @param pelmac The Pelican MAC state
138 @param out [out] The TAG
139 @return CRYPT_OK on sucess
140 */
pelican_done(pelican_state * pelmac,unsigned char * out)141 int pelican_done(pelican_state *pelmac, unsigned char *out)
142 {
143 LTC_ARGCHK(pelmac != NULL);
144 LTC_ARGCHK(out != NULL);
145
146 /* check range */
147 if (pelmac->buflen < 0 || pelmac->buflen > 16) {
148 return CRYPT_INVALID_ARG;
149 }
150
151 if (pelmac->buflen == 16) {
152 four_rounds(pelmac);
153 pelmac->buflen = 0;
154 }
155 pelmac->state[pelmac->buflen++] ^= 0x80;
156 aes_ecb_encrypt(pelmac->state, out, &pelmac->K);
157 aes_done(&pelmac->K);
158 return CRYPT_OK;
159 }
160
161 #endif
162
163 /* $Source: /cvs/libtom/libtomcrypt/src/mac/pelican/pelican.c,v $ */
164 /* $Revision: 1.18 $ */
165 /* $Date: 2006/04/02 13:19:10 $ */
166