1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5 /**
6 @file f9_done.c
7 f9 Support, terminate the state
8 */
9
10 #ifdef LTC_F9_MODE
11
12 /** Terminate the f9-MAC state
13 @param f9 f9 state to terminate
14 @param out [out] Destination for the MAC tag
15 @param outlen [in/out] Destination size and final tag size
16 Return CRYPT_OK on success
17 */
f9_done(f9_state * f9,unsigned char * out,unsigned long * outlen)18 int f9_done(f9_state *f9, unsigned char *out, unsigned long *outlen)
19 {
20 int err, x;
21 LTC_ARGCHK(f9 != NULL);
22 LTC_ARGCHK(out != NULL);
23
24 /* check structure */
25 if ((err = cipher_is_valid(f9->cipher)) != CRYPT_OK) {
26 return err;
27 }
28
29 if ((f9->blocksize > cipher_descriptor[f9->cipher]->block_length) || (f9->blocksize < 0) ||
30 (f9->buflen > f9->blocksize) || (f9->buflen < 0)) {
31 return CRYPT_INVALID_ARG;
32 }
33
34 if (f9->buflen != 0) {
35 /* encrypt */
36 cipher_descriptor[f9->cipher]->ecb_encrypt(f9->IV, f9->IV, &f9->key);
37 f9->buflen = 0;
38 for (x = 0; x < f9->blocksize; x++) {
39 f9->ACC[x] ^= f9->IV[x];
40 }
41 }
42
43 /* schedule modified key */
44 if ((err = cipher_descriptor[f9->cipher]->setup(f9->akey, f9->keylen, 0, &f9->key)) != CRYPT_OK) {
45 return err;
46 }
47
48 /* encrypt the ACC */
49 cipher_descriptor[f9->cipher]->ecb_encrypt(f9->ACC, f9->ACC, &f9->key);
50 cipher_descriptor[f9->cipher]->done(&f9->key);
51
52 /* extract tag */
53 for (x = 0; x < f9->blocksize && (unsigned long)x < *outlen; x++) {
54 out[x] = f9->ACC[x];
55 }
56 *outlen = x;
57
58 #ifdef LTC_CLEAN_STACK
59 zeromem(f9, sizeof(*f9));
60 #endif
61 return CRYPT_OK;
62 }
63
64 #endif
65
66