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0c1f3509 MG |
1 | /*- |
2 | * Copyright 2009 Colin Percival | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * | |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |
15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
24 | * SUCH DAMAGE. | |
25 | * | |
26 | * This file was originally written by Colin Percival as part of the Tarsnap | |
27 | * online backup system. | |
28 | */ | |
29 | #include <stdint.h> | |
30 | ||
31 | #include "sysendian.h" | |
32 | ||
33 | #include "crypto_scrypt_smix.h" | |
34 | ||
35 | static void blkcpy(void *, const void *, size_t); | |
36 | static void blkxor(void *, const void *, size_t); | |
37 | static void salsa20_8(uint32_t[16]); | |
38 | static void blockmix_salsa8(const uint32_t *, uint32_t *, uint32_t *, size_t); | |
39 | static uint64_t integerify(const void *, size_t); | |
40 | ||
41 | static void | |
42 | blkcpy(void * dest, const void * src, size_t len) | |
43 | { | |
44 | size_t * D = dest; | |
45 | const size_t * S = src; | |
46 | size_t L = len / sizeof(size_t); | |
47 | size_t i; | |
48 | ||
49 | for (i = 0; i < L; i++) | |
50 | D[i] = S[i]; | |
51 | } | |
52 | ||
53 | static void | |
54 | blkxor(void * dest, const void * src, size_t len) | |
55 | { | |
56 | size_t * D = dest; | |
57 | const size_t * S = src; | |
58 | size_t L = len / sizeof(size_t); | |
59 | size_t i; | |
60 | ||
61 | for (i = 0; i < L; i++) | |
62 | D[i] ^= S[i]; | |
63 | } | |
64 | ||
65 | /** | |
66 | * salsa20_8(B): | |
67 | * Apply the salsa20/8 core to the provided block. | |
68 | */ | |
69 | static void | |
70 | salsa20_8(uint32_t B[16]) | |
71 | { | |
72 | uint32_t x[16]; | |
73 | size_t i; | |
74 | ||
75 | blkcpy(x, B, 64); | |
76 | for (i = 0; i < 8; i += 2) { | |
77 | #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b)))) | |
78 | /* Operate on columns. */ | |
79 | x[ 4] ^= R(x[ 0]+x[12], 7); x[ 8] ^= R(x[ 4]+x[ 0], 9); | |
80 | x[12] ^= R(x[ 8]+x[ 4],13); x[ 0] ^= R(x[12]+x[ 8],18); | |
81 | ||
82 | x[ 9] ^= R(x[ 5]+x[ 1], 7); x[13] ^= R(x[ 9]+x[ 5], 9); | |
83 | x[ 1] ^= R(x[13]+x[ 9],13); x[ 5] ^= R(x[ 1]+x[13],18); | |
84 | ||
85 | x[14] ^= R(x[10]+x[ 6], 7); x[ 2] ^= R(x[14]+x[10], 9); | |
86 | x[ 6] ^= R(x[ 2]+x[14],13); x[10] ^= R(x[ 6]+x[ 2],18); | |
87 | ||
88 | x[ 3] ^= R(x[15]+x[11], 7); x[ 7] ^= R(x[ 3]+x[15], 9); | |
89 | x[11] ^= R(x[ 7]+x[ 3],13); x[15] ^= R(x[11]+x[ 7],18); | |
90 | ||
91 | /* Operate on rows. */ | |
92 | x[ 1] ^= R(x[ 0]+x[ 3], 7); x[ 2] ^= R(x[ 1]+x[ 0], 9); | |
93 | x[ 3] ^= R(x[ 2]+x[ 1],13); x[ 0] ^= R(x[ 3]+x[ 2],18); | |
94 | ||
95 | x[ 6] ^= R(x[ 5]+x[ 4], 7); x[ 7] ^= R(x[ 6]+x[ 5], 9); | |
96 | x[ 4] ^= R(x[ 7]+x[ 6],13); x[ 5] ^= R(x[ 4]+x[ 7],18); | |
97 | ||
98 | x[11] ^= R(x[10]+x[ 9], 7); x[ 8] ^= R(x[11]+x[10], 9); | |
99 | x[ 9] ^= R(x[ 8]+x[11],13); x[10] ^= R(x[ 9]+x[ 8],18); | |
100 | ||
101 | x[12] ^= R(x[15]+x[14], 7); x[13] ^= R(x[12]+x[15], 9); | |
102 | x[14] ^= R(x[13]+x[12],13); x[15] ^= R(x[14]+x[13],18); | |
103 | #undef R | |
104 | } | |
105 | for (i = 0; i < 16; i++) | |
106 | B[i] += x[i]; | |
107 | } | |
108 | ||
109 | /** | |
110 | * blockmix_salsa8(Bin, Bout, X, r): | |
111 | * Compute Bout = BlockMix_{salsa20/8, r}(Bin). The input Bin must be 128r | |
112 | * bytes in length; the output Bout must also be the same size. The | |
113 | * temporary space X must be 64 bytes. | |
114 | */ | |
115 | static void | |
116 | blockmix_salsa8(const uint32_t * Bin, uint32_t * Bout, uint32_t * X, size_t r) | |
117 | { | |
118 | size_t i; | |
119 | ||
120 | /* 1: X <-- B_{2r - 1} */ | |
121 | blkcpy(X, &Bin[(2 * r - 1) * 16], 64); | |
122 | ||
123 | /* 2: for i = 0 to 2r - 1 do */ | |
124 | for (i = 0; i < 2 * r; i += 2) { | |
125 | /* 3: X <-- H(X \xor B_i) */ | |
126 | blkxor(X, &Bin[i * 16], 64); | |
127 | salsa20_8(X); | |
128 | ||
129 | /* 4: Y_i <-- X */ | |
130 | /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */ | |
131 | blkcpy(&Bout[i * 8], X, 64); | |
132 | ||
133 | /* 3: X <-- H(X \xor B_i) */ | |
134 | blkxor(X, &Bin[i * 16 + 16], 64); | |
135 | salsa20_8(X); | |
136 | ||
137 | /* 4: Y_i <-- X */ | |
138 | /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */ | |
139 | blkcpy(&Bout[i * 8 + r * 16], X, 64); | |
140 | } | |
141 | } | |
142 | ||
143 | /** | |
144 | * integerify(B, r): | |
145 | * Return the result of parsing B_{2r-1} as a little-endian integer. | |
146 | */ | |
147 | static uint64_t | |
148 | integerify(const void * B, size_t r) | |
149 | { | |
150 | const uint32_t * X = (const void *)((uintptr_t)(B) + (2 * r - 1) * 64); | |
151 | ||
152 | return (((uint64_t)(X[1]) << 32) + X[0]); | |
153 | } | |
154 | ||
155 | /** | |
156 | * crypto_scrypt_smix(B, r, N, V, XY): | |
157 | * Compute B = SMix_r(B, N). The input B must be 128r bytes in length; | |
158 | * the temporary storage V must be 128rN bytes in length; the temporary | |
159 | * storage XY must be 256r + 64 bytes in length. The value N must be a | |
160 | * power of 2 greater than 1. The arrays B, V, and XY must be aligned to a | |
161 | * multiple of 64 bytes. | |
162 | */ | |
163 | void | |
164 | crypto_scrypt_smix(uint8_t * B, size_t r, uint64_t N, void * _V, void * XY) | |
165 | { | |
166 | uint32_t * X = XY; | |
167 | uint32_t * Y = (void *)((uint8_t *)(XY) + 128 * r); | |
168 | uint32_t * Z = (void *)((uint8_t *)(XY) + 256 * r); | |
169 | uint32_t * V = _V; | |
170 | uint64_t i; | |
171 | uint64_t j; | |
172 | size_t k; | |
173 | ||
174 | /* 1: X <-- B */ | |
175 | for (k = 0; k < 32 * r; k++) | |
176 | X[k] = le32dec(&B[4 * k]); | |
177 | ||
178 | /* 2: for i = 0 to N - 1 do */ | |
179 | for (i = 0; i < N; i += 2) { | |
180 | /* 3: V_i <-- X */ | |
181 | blkcpy(&V[i * (32 * r)], X, 128 * r); | |
182 | ||
183 | /* 4: X <-- H(X) */ | |
184 | blockmix_salsa8(X, Y, Z, r); | |
185 | ||
186 | /* 3: V_i <-- X */ | |
187 | blkcpy(&V[(i + 1) * (32 * r)], Y, 128 * r); | |
188 | ||
189 | /* 4: X <-- H(X) */ | |
190 | blockmix_salsa8(Y, X, Z, r); | |
191 | } | |
192 | ||
193 | /* 6: for i = 0 to N - 1 do */ | |
194 | for (i = 0; i < N; i += 2) { | |
195 | /* 7: j <-- Integerify(X) mod N */ | |
196 | j = integerify(X, r) & (N - 1); | |
197 | ||
198 | /* 8: X <-- H(X \xor V_j) */ | |
199 | blkxor(X, &V[j * (32 * r)], 128 * r); | |
200 | blockmix_salsa8(X, Y, Z, r); | |
201 | ||
202 | /* 7: j <-- Integerify(X) mod N */ | |
203 | j = integerify(Y, r) & (N - 1); | |
204 | ||
205 | /* 8: X <-- H(X \xor V_j) */ | |
206 | blkxor(Y, &V[j * (32 * r)], 128 * r); | |
207 | blockmix_salsa8(Y, X, Z, r); | |
208 | } | |
209 | ||
210 | /* 10: B' <-- X */ | |
211 | for (k = 0; k < 32 * r; k++) | |
212 | le32enc(&B[4 * k], X[k]); | |
213 | } |