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1 /* | |
2 * Chacha stream algorithm. | |
3 * | |
4 * Created on: Jun, 2013 | |
5 * Author: Elie Bursztein (elieb@google.com) | |
6 * | |
7 * Adapted from the estream code by D. Bernstein. | |
8 */ | |
9 /* ==================================================================== | |
10 * Copyright (c) 2011-2013 The OpenSSL Project. All rights reserved. | |
11 * | |
12 * Redistribution and use in source and binary forms, with or without | |
13 * modification, are permitted provided that the following conditions | |
14 * are met: | |
15 * | |
16 * 1. Redistributions of source code must retain the above copyright | |
17 * notice, this list of conditions and the following disclaimer. | |
18 * | |
19 * 2. Redistributions in binary form must reproduce the above copyright | |
20 * notice, this list of conditions and the following disclaimer in | |
21 * the documentation and/or other materials provided with the | |
22 * distribution. | |
23 * | |
24 * 3. All advertising materials mentioning features or use of this | |
25 * software must display the following acknowledgment: | |
26 * "This product includes software developed by the OpenSSL Project | |
27 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" | |
28 * | |
29 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
30 * endorse or promote products derived from this software without | |
31 * prior written permission. For written permission, please contact | |
32 * licensing@OpenSSL.org. | |
33 * | |
34 * 5. Products derived from this software may not be called "OpenSSL" | |
35 * nor may "OpenSSL" appear in their names without prior written | |
36 * permission of the OpenSSL Project. | |
37 * | |
38 * 6. Redistributions of any form whatsoever must retain the following | |
39 * acknowledgment: | |
40 * "This product includes software developed by the OpenSSL Project | |
41 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" | |
42 * | |
43 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
44 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
46 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
47 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
48 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
49 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
50 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
52 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
53 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
54 * OF THE POSSIBILITY OF SUCH DAMAGE. | |
55 * ==================================================================== | |
56 */ | |
57 | |
58 #include <stdint.h> | |
59 #include <string.h> | |
60 #include <openssl/opensslconf.h> | |
61 | |
62 #if !defined(OPENSSL_NO_CHACHA) | |
63 | |
64 #include <openssl/crypto.h> | |
65 #include <openssl/chacha.h> | |
66 | |
67 /* sigma contains the ChaCha constants, which happen to be an ASCII string. */ | |
68 static const char sigma[16] = "expand 32-byte k"; | |
69 | |
70 #define ROTATE(v, n) (((v) << (n)) | ((v) >> (32 - (n)))) | |
71 #define XOR(v, w) ((v) ^ (w)) | |
72 #define PLUS(x, y) ((x) + (y)) | |
73 #define PLUSONE(v) (PLUS((v), 1)) | |
74 | |
75 #define U32TO8_LITTLE(p, v) \ | |
76 { (p)[0] = (v >> 0) & 0xff; (p)[1] = (v >> 8) & 0xff; \ | |
77 (p)[2] = (v >> 16) & 0xff; (p)[3] = (v >> 24) & 0xff; } | |
78 #define U8TO32_LITTLE(p) \ | |
79 (((uint32_t)((p)[0]) ) | ((uint32_t)((p)[1]) << 8) | \ | |
80 ((uint32_t)((p)[2]) << 16) | ((uint32_t)((p)[3]) << 24) ) | |
81 | |
82 /* QUARTERROUND updates a, b, c, d with a ChaCha "quarter" round. */ | |
83 #define QUARTERROUND(a,b,c,d) \ | |
84 x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \ | |
85 x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \ | |
86 x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \ | |
87 x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7); | |
88 | |
89 typedef unsigned int uint32_t; | |
90 | |
91 #if __arm__ | |
92 /* Defined in chacha_vec.c */ | |
93 void CRYPTO_chacha_20_neon(unsigned char *out, | |
94 const unsigned char *in, size_t in_len, | |
95 const unsigned char key[32], | |
96 const unsigned char nonce[8], | |
97 size_t counter); | |
98 #endif | |
99 | |
100 /* chacha_core performs |num_rounds| rounds of ChaCha20 on the input words in | |
101 * |input| and writes the 64 output bytes to |output|. */ | |
102 static void chacha_core(unsigned char output[64], const uint32_t input[16], | |
103 int num_rounds) | |
104 { | |
105 uint32_t x[16]; | |
106 int i; | |
107 | |
108 memcpy(x, input, sizeof(uint32_t) * 16); | |
109 for (i = 20; i > 0; i -= 2) | |
110 { | |
111 QUARTERROUND( 0, 4, 8,12) | |
112 QUARTERROUND( 1, 5, 9,13) | |
113 QUARTERROUND( 2, 6,10,14) | |
114 QUARTERROUND( 3, 7,11,15) | |
115 QUARTERROUND( 0, 5,10,15) | |
116 QUARTERROUND( 1, 6,11,12) | |
117 QUARTERROUND( 2, 7, 8,13) | |
118 QUARTERROUND( 3, 4, 9,14) | |
119 } | |
120 | |
121 for (i = 0; i < 16; ++i) | |
122 x[i] = PLUS(x[i], input[i]); | |
123 for (i = 0; i < 16; ++i) | |
124 U32TO8_LITTLE(output + 4 * i, x[i]); | |
125 } | |
126 | |
127 void CRYPTO_chacha_20(unsigned char *out, | |
128 const unsigned char *in, size_t in_len, | |
129 const unsigned char key[32], | |
130 const unsigned char nonce[8], | |
131 size_t counter) | |
132 { | |
133 uint32_t input[16]; | |
134 unsigned char buf[64]; | |
135 size_t todo, i; | |
136 | |
137 #if __arm__ | |
138 if (CRYPTO_is_NEON_capable() && | |
139 ((intptr_t)in & 15) == 0 && | |
140 ((intptr_t)out & 15) == 0) | |
141 { | |
142 CRYPTO_chacha_20_neon(out, in, in_len, key, nonce, counter); | |
143 return; | |
144 } | |
145 #endif | |
146 | |
147 input[0] = U8TO32_LITTLE(sigma + 0); | |
148 input[1] = U8TO32_LITTLE(sigma + 4); | |
149 input[2] = U8TO32_LITTLE(sigma + 8); | |
150 input[3] = U8TO32_LITTLE(sigma + 12); | |
151 | |
152 input[4] = U8TO32_LITTLE(key + 0); | |
153 input[5] = U8TO32_LITTLE(key + 4); | |
154 input[6] = U8TO32_LITTLE(key + 8); | |
155 input[7] = U8TO32_LITTLE(key + 12); | |
156 | |
157 input[8] = U8TO32_LITTLE(key + 16); | |
158 input[9] = U8TO32_LITTLE(key + 20); | |
159 input[10] = U8TO32_LITTLE(key + 24); | |
160 input[11] = U8TO32_LITTLE(key + 28); | |
161 | |
162 input[12] = counter; | |
163 input[13] = ((uint64_t) counter) >> 32; | |
164 input[14] = U8TO32_LITTLE(nonce + 0); | |
165 input[15] = U8TO32_LITTLE(nonce + 4); | |
166 | |
167 while (in_len > 0) | |
168 { | |
169 todo = sizeof(buf); | |
170 if (in_len < todo) | |
171 todo = in_len; | |
172 | |
173 chacha_core(buf, input, 20); | |
174 for (i = 0; i < todo; i++) | |
175 out[i] = in[i] ^ buf[i]; | |
176 | |
177 out += todo; | |
178 in += todo; | |
179 in_len -= todo; | |
180 | |
181 input[12]++; | |
182 if (input[12] == 0) | |
183 input[13]++; | |
184 } | |
185 } | |
186 | |
187 #endif /* !OPENSSL_NO_CHACHA */ | |
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