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comparison libtomcrypt/src/encauth/ccm/ccm_done.c @ 1471:6dba84798cd5

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Update to libtomcrypt 1.18.1, merged with Dropbear changes
author Matt Johnston <matt@ucc.asn.au>
date Fri, 09 Feb 2018 21:44:05 +0800
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1470:8bba51a55704 1471:6dba84798cd5
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 #include "tomcrypt.h"
10
11 #ifdef LTC_CCM_MODE
12
13 /**
14 Terminate a CCM stream
15 @param ccm The CCM state
16 @param tag [out] The destination for the MAC tag
17 @param taglen [in/out] The length of the MAC tag
18 @return CRYPT_OK on success
19 */
20 int ccm_done(ccm_state *ccm,
21 unsigned char *tag, unsigned long *taglen)
22 {
23 unsigned long x, y;
24 int err;
25
26 LTC_ARGCHK(ccm != NULL);
27
28 /* Check all data have been processed */
29 if (ccm->ptlen != ccm->current_ptlen) {
30 return CRYPT_ERROR;
31 }
32
33 LTC_ARGCHK(tag != NULL);
34 LTC_ARGCHK(taglen != NULL);
35
36 if (ccm->x != 0) {
37 if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
38 return err;
39 }
40 }
41
42 /* setup CTR for the TAG (zero the count) */
43 for (y = 15; y > 15 - ccm->L; y--) {
44 ccm->ctr[y] = 0x00;
45 }
46 if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->ctr, ccm->CTRPAD, &ccm->K)) != CRYPT_OK) {
47 return err;
48 }
49
50 cipher_descriptor[ccm->cipher].done(&ccm->K);
51
52 /* store the TAG */
53 for (x = 0; x < 16 && x < *taglen; x++) {
54 tag[x] = ccm->PAD[x] ^ ccm->CTRPAD[x];
55 }
56 *taglen = x;
57
58 return CRYPT_OK;
59 }
60
61 #endif
62
63 /* ref: $Format:%D$ */
64 /* git commit: $Format:%H$ */
65 /* commit time: $Format:%ai$ */