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comparison libtomcrypt/src/encauth/chachapoly/chacha20poly1305_setiv_rfc7905.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
10 #include "tomcrypt.h"
11
12 #ifdef LTC_CHACHA20POLY1305_MODE
13
14 /**
15 Set IV + counter data (with RFC7905-magic) to the ChaCha20Poly1305 state and reset the context
16 @param st The ChaCha20Poly1305 state
17 @param iv The IV data to add
18 @param ivlen The length of the IV (must be 12 or 8)
19 @param sequence_number 64bit sequence number which is incorporated into IV as described in RFC7905
20 @return CRYPT_OK on success
21 */
22 int chacha20poly1305_setiv_rfc7905(chacha20poly1305_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 sequence_number)
23 {
24 int i;
25 unsigned char combined_iv[12] = { 0 };
26
27 LTC_ARGCHK(st != NULL);
28 LTC_ARGCHK(iv != NULL);
29 LTC_ARGCHK(ivlen == 12);
30
31 STORE64L(sequence_number, combined_iv + 4);
32 for (i = 0; i < 12; i++) combined_iv[i] = iv[i] ^ combined_iv[i];
33 return chacha20poly1305_setiv(st, combined_iv, 12);
34 }
35
36 #endif
37
38 /* ref: $Format:%D$ */
39 /* git commit: $Format:%H$ */
40 /* commit time: $Format:%ai$ */