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 <stdio.h> 30 #include <stdint.h> 31 #include <string.h> 32 #include <ByteOrder.h> 33 #include "pbkdf2.h" 34 #include "crypto_scrypt_smix.h" 35 36 static void blkcpy(void *, const void *, size_t); 37 static void blkxor(void *, const void *, size_t); 38 static void salsa20_8(uint32_t[16]); 39 static void blockmix_salsa8(const uint32_t *, uint32_t *, uint32_t *, size_t); 40 static uint64_t integerify(const void *, size_t); 41 42 static void 43 blkcpy(void * dest, const void * src, size_t len) 44 { 45 size_t * D = (size_t *)dest; 46 const size_t * S = (const size_t *)src; 47 size_t L = len / sizeof(size_t); 48 size_t i; 49 50 for (i = 0; i < L; i++) 51 D[i] = S[i]; 52 } 53 54 static void 55 blkxor(void * dest, const void * src, size_t len) 56 { 57 size_t * D = (size_t *)dest; 58 const size_t * S = (const size_t *)src; 59 size_t L = len / sizeof(size_t); 60 size_t i; 61 62 for (i = 0; i < L; i++) 63 D[i] ^= S[i]; 64 } 65 66 /** 67 * salsa20_8(B): 68 * Apply the salsa20/8 core to the provided block. 69 */ 70 static void 71 salsa20_8(uint32_t B[16]) 72 { 73 uint32_t x[16]; 74 size_t i; 75 76 blkcpy(x, B, 64); 77 for (i = 0; i < 8; i += 2) { 78 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b)))) 79 /* Operate on columns. */ 80 x[ 4] ^= R(x[ 0]+x[12], 7); x[ 8] ^= R(x[ 4]+x[ 0], 9); 81 x[12] ^= R(x[ 8]+x[ 4],13); x[ 0] ^= R(x[12]+x[ 8],18); 82 83 x[ 9] ^= R(x[ 5]+x[ 1], 7); x[13] ^= R(x[ 9]+x[ 5], 9); 84 x[ 1] ^= R(x[13]+x[ 9],13); x[ 5] ^= R(x[ 1]+x[13],18); 85 86 x[14] ^= R(x[10]+x[ 6], 7); x[ 2] ^= R(x[14]+x[10], 9); 87 x[ 6] ^= R(x[ 2]+x[14],13); x[10] ^= R(x[ 6]+x[ 2],18); 88 89 x[ 3] ^= R(x[15]+x[11], 7); x[ 7] ^= R(x[ 3]+x[15], 9); 90 x[11] ^= R(x[ 7]+x[ 3],13); x[15] ^= R(x[11]+x[ 7],18); 91 92 /* Operate on rows. */ 93 x[ 1] ^= R(x[ 0]+x[ 3], 7); x[ 2] ^= R(x[ 1]+x[ 0], 9); 94 x[ 3] ^= R(x[ 2]+x[ 1],13); x[ 0] ^= R(x[ 3]+x[ 2],18); 95 96 x[ 6] ^= R(x[ 5]+x[ 4], 7); x[ 7] ^= R(x[ 6]+x[ 5], 9); 97 x[ 4] ^= R(x[ 7]+x[ 6],13); x[ 5] ^= R(x[ 4]+x[ 7],18); 98 99 x[11] ^= R(x[10]+x[ 9], 7); x[ 8] ^= R(x[11]+x[10], 9); 100 x[ 9] ^= R(x[ 8]+x[11],13); x[10] ^= R(x[ 9]+x[ 8],18); 101 102 x[12] ^= R(x[15]+x[14], 7); x[13] ^= R(x[12]+x[15], 9); 103 x[14] ^= R(x[13]+x[12],13); x[15] ^= R(x[14]+x[13],18); 104 #undef R 105 } 106 for (i = 0; i < 16; i++) 107 B[i] += x[i]; 108 } 109 110 /** 111 * blockmix_salsa8(Bin, Bout, X, r): 112 * Compute Bout = BlockMix_{salsa20/8, r}(Bin). The input Bin must be 128r 113 * bytes in length; the output Bout must also be the same size. The 114 * temporary space X must be 64 bytes. 115 */ 116 static void 117 blockmix_salsa8(const uint32_t * Bin, uint32_t * Bout, uint32_t * X, size_t r) 118 { 119 size_t i; 120 121 /* 1: X <-- B_{2r - 1} */ 122 blkcpy(X, &Bin[(2 * r - 1) * 16], 64); 123 124 /* 2: for i = 0 to 2r - 1 do */ 125 for (i = 0; i < 2 * r; i += 2) { 126 /* 3: X <-- H(X \xor B_i) */ 127 blkxor(X, &Bin[i * 16], 64); 128 salsa20_8(X); 129 130 /* 4: Y_i <-- X */ 131 /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */ 132 blkcpy(&Bout[i * 8], X, 64); 133 134 /* 3: X <-- H(X \xor B_i) */ 135 blkxor(X, &Bin[i * 16 + 16], 64); 136 salsa20_8(X); 137 138 /* 4: Y_i <-- X */ 139 /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */ 140 blkcpy(&Bout[i * 8 + r * 16], X, 64); 141 } 142 } 143 144 /** 145 * integerify(B, r): 146 * Return the result of parsing B_{2r-1} as a little-endian integer. 147 */ 148 static uint64_t 149 integerify(const void * B, size_t r) 150 { 151 const uint32_t * X = (const uint32_t *)((uintptr_t)(B) + (2 * r - 1) * 64); 152 153 return (((uint64_t)(X[1]) << 32) + X[0]); 154 } 155 156 /** 157 * crypto_scrypt_smix(B, r, N, V, XY): 158 * Compute B = SMix_r(B, N). The input B must be 128r bytes in length; 159 * the temporary storage V must be 128rN bytes in length; the temporary 160 * storage XY must be 256r + 64 bytes in length. The value N must be a 161 * power of 2 greater than 1. The arrays B, V, and XY must be aligned to a 162 * multiple of 64 bytes. 163 */ 164 void 165 crypto_scrypt_smix(uint8_t * B, size_t r, uint64_t N, void * _V, void * XY) 166 { 167 uint32_t * X = (uint32_t *)XY; 168 uint32_t * Y = (uint32_t *)((uint8_t *)(XY) + 128 * r); 169 uint32_t * Z = (uint32_t *)((uint8_t *)(XY) + 256 * r); 170 uint32_t * V = (uint32_t *)_V; 171 uint64_t i; 172 uint64_t j; 173 size_t k; 174 175 /* 1: X <-- B */ 176 for (k = 0; k < 32 * r; k++) { 177 X[k] = B_LENDIAN_TO_HOST_INT32(((uint32_t*)B)[k]); 178 } 179 180 /* 2: for i = 0 to N - 1 do */ 181 for (i = 0; i < N; i += 2) { 182 /* 3: V_i <-- X */ 183 blkcpy(&V[i * (32 * r)], X, 128 * r); 184 185 /* 4: X <-- H(X) */ 186 blockmix_salsa8(X, Y, Z, r); 187 188 /* 3: V_i <-- X */ 189 blkcpy(&V[(i + 1) * (32 * r)], Y, 128 * r); 190 191 /* 4: X <-- H(X) */ 192 blockmix_salsa8(Y, X, Z, r); 193 } 194 195 /* 6: for i = 0 to N - 1 do */ 196 for (i = 0; i < N; i += 2) { 197 /* 7: j <-- Integerify(X) mod N */ 198 j = integerify(X, r) & (N - 1); 199 200 /* 8: X <-- H(X \xor V_j) */ 201 blkxor(X, &V[j * (32 * r)], 128 * r); 202 blockmix_salsa8(X, Y, Z, r); 203 204 /* 7: j <-- Integerify(X) mod N */ 205 j = integerify(Y, r) & (N - 1); 206 207 /* 8: X <-- H(X \xor V_j) */ 208 blkxor(Y, &V[j * (32 * r)], 128 * r); 209 blockmix_salsa8(Y, X, Z, r); 210 } 211 212 /* 10: B' <-- X */ 213 for (k = 0; k < 32 * r; k++) { 214 uint32_t* B32 = &(reinterpret_cast<uint32_t*>(B)[k]); 215 *B32 = B_HOST_TO_LENDIAN_INT32(X[k]); 216 } 217 } 218