/src/nettle/salsa20-core-internal.c
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1 | | /* salsa20-core-internal.c |
2 | | |
3 | | Internal interface to the Salsa20 core function. |
4 | | |
5 | | Copyright (C) 2012 Simon Josefsson, Niels Möller |
6 | | |
7 | | This file is part of GNU Nettle. |
8 | | |
9 | | GNU Nettle is free software: you can redistribute it and/or |
10 | | modify it under the terms of either: |
11 | | |
12 | | * the GNU Lesser General Public License as published by the Free |
13 | | Software Foundation; either version 3 of the License, or (at your |
14 | | option) any later version. |
15 | | |
16 | | or |
17 | | |
18 | | * the GNU General Public License as published by the Free |
19 | | Software Foundation; either version 2 of the License, or (at your |
20 | | option) any later version. |
21 | | |
22 | | or both in parallel, as here. |
23 | | |
24 | | GNU Nettle is distributed in the hope that it will be useful, |
25 | | but WITHOUT ANY WARRANTY; without even the implied warranty of |
26 | | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
27 | | General Public License for more details. |
28 | | |
29 | | You should have received copies of the GNU General Public License and |
30 | | the GNU Lesser General Public License along with this program. If |
31 | | not, see http://www.gnu.org/licenses/. |
32 | | */ |
33 | | |
34 | | /* Based on: |
35 | | salsa20-ref.c version 20051118 |
36 | | D. J. Bernstein |
37 | | Public domain. |
38 | | */ |
39 | | |
40 | | #if HAVE_CONFIG_H |
41 | | # include "config.h" |
42 | | #endif |
43 | | |
44 | | #include <assert.h> |
45 | | #include <string.h> |
46 | | |
47 | | #include "salsa20.h" |
48 | | #include "salsa20-internal.h" |
49 | | |
50 | | #include "bswap-internal.h" |
51 | | #include "macros.h" |
52 | | |
53 | | /* For fat builds */ |
54 | | #if HAVE_NATIVE_salsa20_core |
55 | | void |
56 | | _nettle_salsa20_core_c(uint32_t *dst, const uint32_t *src, unsigned rounds); |
57 | | #define _nettle_salsa20_core _nettle_salsa20_core_c |
58 | | #endif |
59 | | |
60 | | #ifndef SALSA20_DEBUG |
61 | | # define SALSA20_DEBUG 0 |
62 | | #endif |
63 | | |
64 | | #if SALSA20_DEBUG |
65 | | # include <stdio.h> |
66 | | # define DEBUG(i) do { \ |
67 | | unsigned debug_j; \ |
68 | | for (debug_j = 0; debug_j < 16; debug_j++) \ |
69 | | { \ |
70 | | if (debug_j == 0) \ |
71 | | fprintf(stderr, "%2d:", (i)); \ |
72 | | else if (debug_j % 4 == 0) \ |
73 | | fprintf(stderr, "\n "); \ |
74 | | fprintf(stderr, " %8x", x[debug_j]); \ |
75 | | } \ |
76 | | fprintf(stderr, "\n"); \ |
77 | | } while (0) |
78 | | #else |
79 | | # define DEBUG(i) |
80 | | #endif |
81 | | |
82 | 0 | #define QROUND(x0, x1, x2, x3) do { \ |
83 | 0 | x1 ^= ROTL32(7, x0 + x3); \ |
84 | 0 | x2 ^= ROTL32(9, x1 + x0); \ |
85 | 0 | x3 ^= ROTL32(13, x2 + x1); \ |
86 | 0 | x0 ^= ROTL32(18, x3 + x2); \ |
87 | 0 | } while(0) |
88 | | |
89 | | void |
90 | | _nettle_salsa20_core(uint32_t *dst, const uint32_t *src, unsigned rounds) |
91 | 0 | { |
92 | 0 | uint32_t x[_SALSA20_INPUT_LENGTH]; |
93 | 0 | unsigned i; |
94 | |
|
95 | 0 | assert ( (rounds & 1) == 0); |
96 | | |
97 | 0 | memcpy (x, src, sizeof(x)); |
98 | 0 | for (i = 0; i < rounds;i += 2) |
99 | 0 | { |
100 | 0 | DEBUG (i); |
101 | 0 | QROUND(x[0], x[4], x[8], x[12]); |
102 | 0 | QROUND(x[5], x[9], x[13], x[1]); |
103 | 0 | QROUND(x[10], x[14], x[2], x[6]); |
104 | 0 | QROUND(x[15], x[3], x[7], x[11]); |
105 | |
|
106 | 0 | DEBUG (i+1); |
107 | 0 | QROUND(x[0], x[1], x[2], x[3]); |
108 | 0 | QROUND(x[5], x[6], x[7], x[4]); |
109 | 0 | QROUND(x[10], x[11], x[8], x[9]); |
110 | 0 | QROUND(x[15], x[12], x[13], x[14]); |
111 | 0 | } |
112 | 0 | DEBUG (i); |
113 | |
|
114 | 0 | for (i = 0; i < _SALSA20_INPUT_LENGTH; i++) |
115 | 0 | { |
116 | 0 | uint32_t t = x[i] + src[i]; |
117 | 0 | dst[i] = bswap32_if_be (t); |
118 | 0 | } |
119 | 0 | } |