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comparison libtomcrypt/src/mac/pmac/pmac_init.c @ 389:5ff8218bcee9

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e) to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 03:14:55 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
comparison
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388:fb54020f78e1 389:5ff8218bcee9
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, [email protected], http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file pmac_init.c
15 PMAC implementation, initialize state, by Tom St Denis
16 */
17
18 #ifdef LTC_PMAC
19
20 static const struct {
21 int len;
22 unsigned char poly_div[MAXBLOCKSIZE],
23 poly_mul[MAXBLOCKSIZE];
24 } polys[] = {
25 {
26 8,
27 { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0D },
28 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1B }
29 }, {
30 16,
31 { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
32 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x43 },
33 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
34 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x87 }
35 }
36 };
37
38 /**
39 Initialize a PMAC state
40 @param pmac The PMAC state to initialize
41 @param cipher The index of the desired cipher
42 @param key The secret key
43 @param keylen The length of the secret key (octets)
44 @return CRYPT_OK if successful
45 */
46 int pmac_init(pmac_state *pmac, int cipher, const unsigned char *key, unsigned long keylen)
47 {
48 int poly, x, y, m, err;
49 unsigned char *L;
50
51 LTC_ARGCHK(pmac != NULL);
52 LTC_ARGCHK(key != NULL);
53
54 /* valid cipher? */
55 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
56 return err;
57 }
58
59 /* determine which polys to use */
60 pmac->block_len = cipher_descriptor[cipher].block_length;
61 for (poly = 0; poly < (int)(sizeof(polys)/sizeof(polys[0])); poly++) {
62 if (polys[poly].len == pmac->block_len) {
63 break;
64 }
65 }
66 if (polys[poly].len != pmac->block_len) {
67 return CRYPT_INVALID_ARG;
68 }
69
70 #ifdef LTC_FAST
71 if (pmac->block_len % sizeof(LTC_FAST_TYPE)) {
72 return CRYPT_INVALID_ARG;
73 }
74 #endif
75
76
77 /* schedule the key */
78 if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, &pmac->key)) != CRYPT_OK) {
79 return err;
80 }
81
82 /* allocate L */
83 L = XMALLOC(pmac->block_len);
84 if (L == NULL) {
85 return CRYPT_MEM;
86 }
87
88 /* find L = E[0] */
89 zeromem(L, pmac->block_len);
90 if ((err = cipher_descriptor[cipher].ecb_encrypt(L, L, &pmac->key)) != CRYPT_OK) {
91 goto error;
92 }
93
94 /* find Ls[i] = L << i for i == 0..31 */
95 XMEMCPY(pmac->Ls[0], L, pmac->block_len);
96 for (x = 1; x < 32; x++) {
97 m = pmac->Ls[x-1][0] >> 7;
98 for (y = 0; y < pmac->block_len-1; y++) {
99 pmac->Ls[x][y] = ((pmac->Ls[x-1][y] << 1) | (pmac->Ls[x-1][y+1] >> 7)) & 255;
100 }
101 pmac->Ls[x][pmac->block_len-1] = (pmac->Ls[x-1][pmac->block_len-1] << 1) & 255;
102
103 if (m == 1) {
104 for (y = 0; y < pmac->block_len; y++) {
105 pmac->Ls[x][y] ^= polys[poly].poly_mul[y];
106 }
107 }
108 }
109
110 /* find Lr = L / x */
111 m = L[pmac->block_len-1] & 1;
112
113 /* shift right */
114 for (x = pmac->block_len - 1; x > 0; x--) {
115 pmac->Lr[x] = ((L[x] >> 1) | (L[x-1] << 7)) & 255;
116 }
117 pmac->Lr[0] = L[0] >> 1;
118
119 if (m == 1) {
120 for (x = 0; x < pmac->block_len; x++) {
121 pmac->Lr[x] ^= polys[poly].poly_div[x];
122 }
123 }
124
125 /* zero buffer, counters, etc... */
126 pmac->block_index = 1;
127 pmac->cipher_idx = cipher;
128 pmac->buflen = 0;
129 zeromem(pmac->block, sizeof(pmac->block));
130 zeromem(pmac->Li, sizeof(pmac->Li));
131 zeromem(pmac->checksum, sizeof(pmac->checksum));
132 err = CRYPT_OK;
133 error:
134 #ifdef LTC_CLEAN_STACK
135 zeromem(L, pmac->block_len);
136 #endif
137
138 XFREE(L);
139
140 return err;
141 }
142
143 #endif
144
145 /* $Source: /cvs/libtom/libtomcrypt/src/mac/pmac/pmac_init.c,v $ */
146 /* $Revision: 1.7 $ */
147 /* $Date: 2006/11/03 00:39:49 $ */