| 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 | } |