2 * Copyright 2009 Colin Percival
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
26 * This file was originally written by Colin Percival as part of the Tarsnap
27 * online backup system.
29 #include "scrypt_platform.h"
37 #include "sysendian.h"
39 #include "crypto_scrypt.h"
41 static void blkcpy(uint8_t *, uint8_t *, size_t);
42 static void blkxor(uint8_t *, uint8_t *, size_t);
43 static void salsa20_8(uint8_t[64]);
44 static void blockmix_salsa8(uint8_t *, uint8_t *, size_t);
45 static uint64_t integerify(uint8_t *, size_t);
46 static void smix(uint8_t *, size_t, uint64_t, uint8_t *, uint8_t *);
49 blkcpy(uint8_t * dest, uint8_t * src, size_t len)
53 for (i = 0; i < len; i++)
58 blkxor(uint8_t * dest, uint8_t * src, size_t len)
62 for (i = 0; i < len; i++)
68 * Apply the salsa20/8 core to the provided block.
71 salsa20_8(uint8_t B[64])
77 /* Convert little-endian values in. */
78 for (i = 0; i < 16; i++)
79 B32[i] = le32dec(&B[i * 4]);
81 /* Compute x = doubleround^4(B32). */
82 for (i = 0; i < 16; i++)
84 for (i = 0; i < 8; i += 2) {
85 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
86 /* Operate on columns. */
87 x[ 4] ^= R(x[ 0]+x[12], 7); x[ 8] ^= R(x[ 4]+x[ 0], 9);
88 x[12] ^= R(x[ 8]+x[ 4],13); x[ 0] ^= R(x[12]+x[ 8],18);
90 x[ 9] ^= R(x[ 5]+x[ 1], 7); x[13] ^= R(x[ 9]+x[ 5], 9);
91 x[ 1] ^= R(x[13]+x[ 9],13); x[ 5] ^= R(x[ 1]+x[13],18);
93 x[14] ^= R(x[10]+x[ 6], 7); x[ 2] ^= R(x[14]+x[10], 9);
94 x[ 6] ^= R(x[ 2]+x[14],13); x[10] ^= R(x[ 6]+x[ 2],18);
96 x[ 3] ^= R(x[15]+x[11], 7); x[ 7] ^= R(x[ 3]+x[15], 9);
97 x[11] ^= R(x[ 7]+x[ 3],13); x[15] ^= R(x[11]+x[ 7],18);
99 /* Operate on rows. */
100 x[ 1] ^= R(x[ 0]+x[ 3], 7); x[ 2] ^= R(x[ 1]+x[ 0], 9);
101 x[ 3] ^= R(x[ 2]+x[ 1],13); x[ 0] ^= R(x[ 3]+x[ 2],18);
103 x[ 6] ^= R(x[ 5]+x[ 4], 7); x[ 7] ^= R(x[ 6]+x[ 5], 9);
104 x[ 4] ^= R(x[ 7]+x[ 6],13); x[ 5] ^= R(x[ 4]+x[ 7],18);
106 x[11] ^= R(x[10]+x[ 9], 7); x[ 8] ^= R(x[11]+x[10], 9);
107 x[ 9] ^= R(x[ 8]+x[11],13); x[10] ^= R(x[ 9]+x[ 8],18);
109 x[12] ^= R(x[15]+x[14], 7); x[13] ^= R(x[12]+x[15], 9);
110 x[14] ^= R(x[13]+x[12],13); x[15] ^= R(x[14]+x[13],18);
114 /* Compute B32 = B32 + x. */
115 for (i = 0; i < 16; i++)
118 /* Convert little-endian values out. */
119 for (i = 0; i < 16; i++)
120 le32enc(&B[4 * i], B32[i]);
124 * blockmix_salsa8(B, Y, r):
125 * Compute B = BlockMix_{salsa20/8, r}(B). The input B must be 128r bytes in
126 * length; the temporary space Y must also be the same size.
129 blockmix_salsa8(uint8_t * B, uint8_t * Y, size_t r)
134 /* 1: X <-- B_{2r - 1} */
135 blkcpy(X, &B[(2 * r - 1) * 64], 64);
137 /* 2: for i = 0 to 2r - 1 do */
138 for (i = 0; i < 2 * r; i++) {
139 /* 3: X <-- H(X \xor B_i) */
140 blkxor(X, &B[i * 64], 64);
144 blkcpy(&Y[i * 64], X, 64);
147 /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */
148 for (i = 0; i < r; i++)
149 blkcpy(&B[i * 64], &Y[(i * 2) * 64], 64);
150 for (i = 0; i < r; i++)
151 blkcpy(&B[(i + r) * 64], &Y[(i * 2 + 1) * 64], 64);
156 * Return the result of parsing B_{2r-1} as a little-endian integer.
159 integerify(uint8_t * B, size_t r)
161 uint8_t * X = &B[(2 * r - 1) * 64];
167 * smix(B, r, N, V, XY):
168 * Compute B = SMix_r(B, N). The input B must be 128r bytes in length; the
169 * temporary storage V must be 128rN bytes in length; the temporary storage
170 * XY must be 256r bytes in length. The value N must be a power of 2.
173 smix(uint8_t * B, size_t r, uint64_t N, uint8_t * V, uint8_t * XY)
176 uint8_t * Y = &XY[128 * r];
181 blkcpy(X, B, 128 * r);
183 /* 2: for i = 0 to N - 1 do */
184 for (i = 0; i < N; i++) {
186 blkcpy(&V[i * (128 * r)], X, 128 * r);
189 blockmix_salsa8(X, Y, r);
192 /* 6: for i = 0 to N - 1 do */
193 for (i = 0; i < N; i++) {
194 /* 7: j <-- Integerify(X) mod N */
195 j = integerify(X, r) & (N - 1);
197 /* 8: X <-- H(X \xor V_j) */
198 blkxor(X, &V[j * (128 * r)], 128 * r);
199 blockmix_salsa8(X, Y, r);
203 blkcpy(B, X, 128 * r);
207 * crypto_scrypt(passwd, passwdlen, salt, saltlen, N, r, p, buf, buflen):
208 * Compute scrypt(passwd[0 .. passwdlen - 1], salt[0 .. saltlen - 1], N, r,
209 * p, buflen) and write the result into buf. The parameters r, p, and buflen
210 * must satisfy r * p < 2^30 and buflen <= (2^32 - 1) * 32. The parameter N
211 * must be a power of 2.
213 * Return 0 on success; or -1 on error.
216 crypto_scrypt(const uint8_t * passwd, size_t passwdlen,
217 const uint8_t * salt, size_t saltlen, uint64_t N, uint32_t r, uint32_t p,
218 uint8_t * buf, size_t buflen)
225 /* Sanity-check parameters. */
226 #if SIZE_MAX > UINT32_MAX
227 if (buflen > (((uint64_t)(1) << 32) - 1) * 32) {
232 if ((uint64_t)(r) * (uint64_t)(p) >= (1 << 30)) {
236 if (((N & (N - 1)) != 0) || (N == 0)) {
240 if ((r > SIZE_MAX / 128 / p) ||
241 #if SIZE_MAX / 256 <= UINT32_MAX
242 (r > SIZE_MAX / 256) ||
244 (N > SIZE_MAX / 128 / r)) {
249 /* Allocate memory. */
250 if ((B = malloc(128 * r * p)) == NULL)
252 if ((XY = malloc(256 * r)) == NULL)
254 if ((V = malloc(128 * r * N)) == NULL)
257 /* 1: (B_0 ... B_{p-1}) <-- PBKDF2(P, S, 1, p * MFLen) */
258 PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, 1, B, p * 128 * r);
260 /* 2: for i = 0 to p - 1 do */
261 for (i = 0; i < p; i++) {
262 /* 3: B_i <-- MF(B_i, N) */
263 smix(&B[i * 128 * r], r, N, V, XY);
266 /* 5: DK <-- PBKDF2(P, B, 1, dkLen) */
267 PBKDF2_SHA256(passwd, passwdlen, B, p * 128 * r, 1, buf, buflen);