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 f9_done.c
15 f9 Support, terminate the state
16 */
17
18 #ifdef LTC_F9_MODE
19
20 /** Terminate the f9-MAC state
21 @param f9 f9 state to terminate
22 @param out [out] Destination for the MAC tag
23 @param outlen [in/out] Destination size and final tag size
24 Return CRYPT_OK on success
25 */
f9_done(f9_state * f9,unsigned char * out,unsigned long * outlen)26 int f9_done(f9_state *f9, unsigned char *out, unsigned long *outlen)
27 {
28 int err, x;
29 LTC_ARGCHK(f9 != NULL);
30 LTC_ARGCHK(out != NULL);
31
32 /* check structure */
33 if ((err = cipher_is_valid(f9->cipher)) != CRYPT_OK) {
34 return err;
35 }
36
37 if ((f9->blocksize > cipher_descriptor[f9->cipher].block_length) || (f9->blocksize < 0) ||
38 (f9->buflen > f9->blocksize) || (f9->buflen < 0)) {
39 return CRYPT_INVALID_ARG;
40 }
41
42 if (f9->buflen != 0) {
43 /* encrypt */
44 cipher_descriptor[f9->cipher].ecb_encrypt(f9->IV, f9->IV, &f9->key);
45 f9->buflen = 0;
46 for (x = 0; x < f9->blocksize; x++) {
47 f9->ACC[x] ^= f9->IV[x];
48 }
49 }
50
51 /* schedule modified key */
52 if ((err = cipher_descriptor[f9->cipher].setup(f9->akey, f9->keylen, 0, &f9->key)) != CRYPT_OK) {
53 return err;
54 }
55
56 /* encrypt the ACC */
57 cipher_descriptor[f9->cipher].ecb_encrypt(f9->ACC, f9->ACC, &f9->key);
58 cipher_descriptor[f9->cipher].done(&f9->key);
59
60 /* extract tag */
61 for (x = 0; x < f9->blocksize && (unsigned long)x < *outlen; x++) {
62 out[x] = f9->ACC[x];
63 }
64 *outlen = x;
65
66 #ifdef LTC_CLEAN_STACK
67 zeromem(f9, sizeof(*f9));
68 #endif
69 return CRYPT_OK;
70 }
71
72 #endif
73
74 /* $Source: /cvs/libtom/libtomcrypt/src/mac/f9/f9_done.c,v $ */
75 /* $Revision: 1.5 $ */
76 /* $Date: 2006/11/09 01:53:32 $ */
77
78