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comparison libtomcrypt/src/encauth/ccm/ccm_add_aad.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 Add AAD to the CCM state
15 @param ccm The CCM state
16 @param adata The additional authentication data to add to the CCM state
17 @param adatalen The length of the AAD data.
18 @return CRYPT_OK on success
19 */
20 int ccm_add_aad(ccm_state *ccm,
21 const unsigned char *adata, unsigned long adatalen)
22 {
23 unsigned long y;
24 int err;
25
26 LTC_ARGCHK(ccm != NULL);
27 LTC_ARGCHK(adata != NULL);
28
29 if (ccm->aadlen < ccm->current_aadlen + adatalen) {
30 return CRYPT_INVALID_ARG;
31 }
32 ccm->current_aadlen += adatalen;
33
34 /* now add the data */
35 for (y = 0; y < adatalen; y++) {
36 if (ccm->x == 16) {
37 /* full block so let's encrypt it */
38 if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
39 return err;
40 }
41 ccm->x = 0;
42 }
43 ccm->PAD[ccm->x++] ^= adata[y];
44 }
45
46 /* remainder? */
47 if (ccm->aadlen == ccm->current_aadlen) {
48 if (ccm->x != 0) {
49 if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
50 return err;
51 }
52 }
53 ccm->x = 0;
54 }
55
56 return CRYPT_OK;
57 }
58
59 #endif
60
61 /* ref: $Format:%D$ */
62 /* git commit: $Format:%H$ */
63 /* commit time: $Format:%ai$ */