Mercurial > dropbear
comparison libtomcrypt/src/stream/chacha/chacha_setup.c @ 1471:6dba84798cd5
Update to libtomcrypt 1.18.1, merged with Dropbear changes
author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 09 Feb 2018 21:44:05 +0800 |
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1470:8bba51a55704 | 1471:6dba84798cd5 |
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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 /* The implementation is based on: | |
11 * chacha-ref.c version 20080118 | |
12 * Public domain from D. J. Bernstein | |
13 */ | |
14 | |
15 #include "tomcrypt.h" | |
16 | |
17 #ifdef LTC_CHACHA | |
18 | |
19 static const char * const sigma = "expand 32-byte k"; | |
20 static const char * const tau = "expand 16-byte k"; | |
21 | |
22 /** | |
23 Initialize an ChaCha context (only the key) | |
24 @param st [out] The destination of the ChaCha state | |
25 @param key The secret key | |
26 @param keylen The length of the secret key (octets) | |
27 @param rounds Number of rounds (e.g. 20 for ChaCha20) | |
28 @return CRYPT_OK if successful | |
29 */ | |
30 int chacha_setup(chacha_state *st, const unsigned char *key, unsigned long keylen, int rounds) | |
31 { | |
32 const char *constants; | |
33 | |
34 LTC_ARGCHK(st != NULL); | |
35 LTC_ARGCHK(key != NULL); | |
36 LTC_ARGCHK(keylen == 32 || keylen == 16); | |
37 | |
38 if (rounds == 0) rounds = 20; | |
39 | |
40 LOAD32L(st->input[4], key + 0); | |
41 LOAD32L(st->input[5], key + 4); | |
42 LOAD32L(st->input[6], key + 8); | |
43 LOAD32L(st->input[7], key + 12); | |
44 if (keylen == 32) { /* 256bit */ | |
45 key += 16; | |
46 constants = sigma; | |
47 } else { /* 128bit */ | |
48 constants = tau; | |
49 } | |
50 LOAD32L(st->input[8], key + 0); | |
51 LOAD32L(st->input[9], key + 4); | |
52 LOAD32L(st->input[10], key + 8); | |
53 LOAD32L(st->input[11], key + 12); | |
54 LOAD32L(st->input[0], constants + 0); | |
55 LOAD32L(st->input[1], constants + 4); | |
56 LOAD32L(st->input[2], constants + 8); | |
57 LOAD32L(st->input[3], constants + 12); | |
58 st->rounds = rounds; /* e.g. 20 for chacha20 */ | |
59 st->ivlen = 0; /* will be set later by chacha_ivctr(32|64) */ | |
60 return CRYPT_OK; | |
61 } | |
62 | |
63 #endif | |
64 | |
65 /* ref: $Format:%D$ */ | |
66 /* git commit: $Format:%H$ */ | |
67 /* commit time: $Format:%ai$ */ |