|
380
|
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 xcbc_init.c |
|
|
15 XCBC Support, start an XCBC state |
|
|
16 */ |
|
|
17 |
|
|
18 #ifdef LTC_XCBC |
|
|
19 |
|
|
20 /** Initialize XCBC-MAC state |
|
|
21 @param xcbc [out] XCBC state to initialize |
|
|
22 @param cipher Index of cipher to use |
|
|
23 @param key [in] Secret key |
|
|
24 @param keylen Length of secret key in octets |
|
|
25 Return CRYPT_OK on success |
|
|
26 */ |
|
|
27 int xcbc_init(xcbc_state *xcbc, int cipher, const unsigned char *key, unsigned long keylen) |
|
|
28 { |
|
|
29 int x, y, err; |
|
|
30 symmetric_key *skey; |
|
|
31 |
|
|
32 LTC_ARGCHK(xcbc != NULL); |
|
|
33 LTC_ARGCHK(key != NULL); |
|
|
34 |
|
|
35 /* schedule the key */ |
|
|
36 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { |
|
|
37 return err; |
|
|
38 } |
|
|
39 |
|
|
40 #ifdef LTC_FAST |
|
|
41 if (cipher_descriptor[cipher].block_length % sizeof(LTC_FAST_TYPE)) { |
|
|
42 return CRYPT_INVALID_ARG; |
|
|
43 } |
|
|
44 #endif |
|
|
45 |
|
|
46 /* schedule the user key */ |
|
|
47 skey = XCALLOC(1, sizeof(*skey)); |
|
|
48 if (skey == NULL) { |
|
|
49 return CRYPT_MEM; |
|
|
50 } |
|
|
51 |
|
|
52 if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, skey)) != CRYPT_OK) { |
|
|
53 goto done; |
|
|
54 } |
|
|
55 |
|
|
56 /* make the three keys */ |
|
|
57 for (y = 0; y < 3; y++) { |
|
|
58 for (x = 0; x < cipher_descriptor[cipher].block_length; x++) { |
|
|
59 xcbc->K[y][x] = y + 1; |
|
|
60 } |
|
|
61 cipher_descriptor[cipher].ecb_encrypt(xcbc->K[y], xcbc->K[y], skey); |
|
|
62 } |
|
|
63 |
|
|
64 /* setup K1 */ |
|
|
65 err = cipher_descriptor[cipher].setup(xcbc->K[0], cipher_descriptor[cipher].block_length, 0, &xcbc->key); |
|
|
66 |
|
|
67 /* setup struct */ |
|
|
68 zeromem(xcbc->IV, cipher_descriptor[cipher].block_length); |
|
|
69 xcbc->blocksize = cipher_descriptor[cipher].block_length; |
|
|
70 xcbc->cipher = cipher; |
|
|
71 xcbc->buflen = 0; |
|
|
72 done: |
|
|
73 cipher_descriptor[cipher].done(skey); |
|
|
74 #ifdef LTC_CLEAN_STACK |
|
|
75 zeromem(skey, sizeof(*skey)); |
|
|
76 #endif |
|
|
77 XFREE(skey); |
|
|
78 return err; |
|
|
79 } |
|
|
80 |
|
|
81 #endif |
|
|
82 |
|
|
83 /* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_init.c,v $ */ |
|
|
84 /* $Revision: 1.4 $ */ |
|
|
85 /* $Date: 2006/11/07 03:23:46 $ */ |
|
|
86 |
