--- /dev/null
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package scrypt implements the scrypt key derivation function as defined in
+// Colin Percival's paper "Stronger Key Derivation via Sequential Memory-Hard
+// Functions" (https://www.tarsnap.com/scrypt/scrypt.pdf).
+package scrypt // import "golang.org/x/crypto/scrypt"
+
+import (
+ "crypto/sha256"
+ "errors"
+
+ "golang.org/x/crypto/pbkdf2"
+)
+
+const maxInt = int(^uint(0) >> 1)
+
+// blockCopy copies n numbers from src into dst.
+func blockCopy(dst, src []uint32, n int) {
+ copy(dst, src[:n])
+}
+
+// blockXOR XORs numbers from dst with n numbers from src.
+func blockXOR(dst, src []uint32, n int) {
+ for i, v := range src[:n] {
+ dst[i] ^= v
+ }
+}
+
+// salsaXOR applies Salsa20/8 to the XOR of 16 numbers from tmp and in,
+// and puts the result into both both tmp and out.
+func salsaXOR(tmp *[16]uint32, in, out []uint32) {
+ w0 := tmp[0] ^ in[0]
+ w1 := tmp[1] ^ in[1]
+ w2 := tmp[2] ^ in[2]
+ w3 := tmp[3] ^ in[3]
+ w4 := tmp[4] ^ in[4]
+ w5 := tmp[5] ^ in[5]
+ w6 := tmp[6] ^ in[6]
+ w7 := tmp[7] ^ in[7]
+ w8 := tmp[8] ^ in[8]
+ w9 := tmp[9] ^ in[9]
+ w10 := tmp[10] ^ in[10]
+ w11 := tmp[11] ^ in[11]
+ w12 := tmp[12] ^ in[12]
+ w13 := tmp[13] ^ in[13]
+ w14 := tmp[14] ^ in[14]
+ w15 := tmp[15] ^ in[15]
+
+ x0, x1, x2, x3, x4, x5, x6, x7, x8 := w0, w1, w2, w3, w4, w5, w6, w7, w8
+ x9, x10, x11, x12, x13, x14, x15 := w9, w10, w11, w12, w13, w14, w15
+
+ for i := 0; i < 8; i += 2 {
+ u := x0 + x12
+ x4 ^= u<<7 | u>>(32-7)
+ u = x4 + x0
+ x8 ^= u<<9 | u>>(32-9)
+ u = x8 + x4
+ x12 ^= u<<13 | u>>(32-13)
+ u = x12 + x8
+ x0 ^= u<<18 | u>>(32-18)
+
+ u = x5 + x1
+ x9 ^= u<<7 | u>>(32-7)
+ u = x9 + x5
+ x13 ^= u<<9 | u>>(32-9)
+ u = x13 + x9
+ x1 ^= u<<13 | u>>(32-13)
+ u = x1 + x13
+ x5 ^= u<<18 | u>>(32-18)
+
+ u = x10 + x6
+ x14 ^= u<<7 | u>>(32-7)
+ u = x14 + x10
+ x2 ^= u<<9 | u>>(32-9)
+ u = x2 + x14
+ x6 ^= u<<13 | u>>(32-13)
+ u = x6 + x2
+ x10 ^= u<<18 | u>>(32-18)
+
+ u = x15 + x11
+ x3 ^= u<<7 | u>>(32-7)
+ u = x3 + x15
+ x7 ^= u<<9 | u>>(32-9)
+ u = x7 + x3
+ x11 ^= u<<13 | u>>(32-13)
+ u = x11 + x7
+ x15 ^= u<<18 | u>>(32-18)
+
+ u = x0 + x3
+ x1 ^= u<<7 | u>>(32-7)
+ u = x1 + x0
+ x2 ^= u<<9 | u>>(32-9)
+ u = x2 + x1
+ x3 ^= u<<13 | u>>(32-13)
+ u = x3 + x2
+ x0 ^= u<<18 | u>>(32-18)
+
+ u = x5 + x4
+ x6 ^= u<<7 | u>>(32-7)
+ u = x6 + x5
+ x7 ^= u<<9 | u>>(32-9)
+ u = x7 + x6
+ x4 ^= u<<13 | u>>(32-13)
+ u = x4 + x7
+ x5 ^= u<<18 | u>>(32-18)
+
+ u = x10 + x9
+ x11 ^= u<<7 | u>>(32-7)
+ u = x11 + x10
+ x8 ^= u<<9 | u>>(32-9)
+ u = x8 + x11
+ x9 ^= u<<13 | u>>(32-13)
+ u = x9 + x8
+ x10 ^= u<<18 | u>>(32-18)
+
+ u = x15 + x14
+ x12 ^= u<<7 | u>>(32-7)
+ u = x12 + x15
+ x13 ^= u<<9 | u>>(32-9)
+ u = x13 + x12
+ x14 ^= u<<13 | u>>(32-13)
+ u = x14 + x13
+ x15 ^= u<<18 | u>>(32-18)
+ }
+ x0 += w0
+ x1 += w1
+ x2 += w2
+ x3 += w3
+ x4 += w4
+ x5 += w5
+ x6 += w6
+ x7 += w7
+ x8 += w8
+ x9 += w9
+ x10 += w10
+ x11 += w11
+ x12 += w12
+ x13 += w13
+ x14 += w14
+ x15 += w15
+
+ out[0], tmp[0] = x0, x0
+ out[1], tmp[1] = x1, x1
+ out[2], tmp[2] = x2, x2
+ out[3], tmp[3] = x3, x3
+ out[4], tmp[4] = x4, x4
+ out[5], tmp[5] = x5, x5
+ out[6], tmp[6] = x6, x6
+ out[7], tmp[7] = x7, x7
+ out[8], tmp[8] = x8, x8
+ out[9], tmp[9] = x9, x9
+ out[10], tmp[10] = x10, x10
+ out[11], tmp[11] = x11, x11
+ out[12], tmp[12] = x12, x12
+ out[13], tmp[13] = x13, x13
+ out[14], tmp[14] = x14, x14
+ out[15], tmp[15] = x15, x15
+}
+
+func blockMix(tmp *[16]uint32, in, out []uint32, r int) {
+ blockCopy(tmp[:], in[(2*r-1)*16:], 16)
+ for i := 0; i < 2*r; i += 2 {
+ salsaXOR(tmp, in[i*16:], out[i*8:])
+ salsaXOR(tmp, in[i*16+16:], out[i*8+r*16:])
+ }
+}
+
+func integer(b []uint32, r int) uint64 {
+ j := (2*r - 1) * 16
+ return uint64(b[j]) | uint64(b[j+1])<<32
+}
+
+func smix(b []byte, r, N int, v, xy []uint32) {
+ var tmp [16]uint32
+ x := xy
+ y := xy[32*r:]
+
+ j := 0
+ for i := 0; i < 32*r; i++ {
+ x[i] = uint32(b[j]) | uint32(b[j+1])<<8 | uint32(b[j+2])<<16 | uint32(b[j+3])<<24
+ j += 4
+ }
+ for i := 0; i < N; i += 2 {
+ blockCopy(v[i*(32*r):], x, 32*r)
+ blockMix(&tmp, x, y, r)
+
+ blockCopy(v[(i+1)*(32*r):], y, 32*r)
+ blockMix(&tmp, y, x, r)
+ }
+ for i := 0; i < N; i += 2 {
+ j := int(integer(x, r) & uint64(N-1))
+ blockXOR(x, v[j*(32*r):], 32*r)
+ blockMix(&tmp, x, y, r)
+
+ j = int(integer(y, r) & uint64(N-1))
+ blockXOR(y, v[j*(32*r):], 32*r)
+ blockMix(&tmp, y, x, r)
+ }
+ j = 0
+ for _, v := range x[:32*r] {
+ b[j+0] = byte(v >> 0)
+ b[j+1] = byte(v >> 8)
+ b[j+2] = byte(v >> 16)
+ b[j+3] = byte(v >> 24)
+ j += 4
+ }
+}
+
+// Key derives a key from the password, salt, and cost parameters, returning
+// a byte slice of length keyLen that can be used as cryptographic key.
+//
+// N is a CPU/memory cost parameter, which must be a power of two greater than 1.
+// r and p must satisfy r * p < 2³⁰. If the parameters do not satisfy the
+// limits, the function returns a nil byte slice and an error.
+//
+// For example, you can get a derived key for e.g. AES-256 (which needs a
+// 32-byte key) by doing:
+//
+// dk, err := scrypt.Key([]byte("some password"), salt, 16384, 8, 1, 32)
+//
+// The recommended parameters for interactive logins as of 2009 are N=16384,
+// r=8, p=1. They should be increased as memory latency and CPU parallelism
+// increases. Remember to get a good random salt.
+func Key(password, salt []byte, N, r, p, keyLen int) ([]byte, error) {
+ if N <= 1 || N&(N-1) != 0 {
+ return nil, errors.New("scrypt: N must be > 1 and a power of 2")
+ }
+ if uint64(r)*uint64(p) >= 1<<30 || r > maxInt/128/p || r > maxInt/256 || N > maxInt/128/r {
+ return nil, errors.New("scrypt: parameters are too large")
+ }
+
+ xy := make([]uint32, 64*r)
+ v := make([]uint32, 32*N*r)
+ b := pbkdf2.Key(password, salt, 1, p*128*r, sha256.New)
+
+ for i := 0; i < p; i++ {
+ smix(b[i*128*r:], r, N, v, xy)
+ }
+
+ return pbkdf2.Key(password, b, 1, keyLen, sha256.New), nil
+}
OSDN Git Service
