From 6ba10a7acbbf2ad7cc0e72a5a9c60fc304c09461 Mon Sep 17 00:00:00 2001 From: Dmitry Chestnykh Date: Tue, 18 Sep 2012 16:59:45 -0400 Subject: [PATCH] go.crypto/scrypt: add package R=golang-dev, agl, r CC=golang-dev https://golang.org/cl/6535043 --- scrypt/scrypt.go | 109 ++++++++++++++++++++++++++++++++++++++++ scrypt/scrypt_test.go | 112 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 221 insertions(+) create mode 100644 scrypt/scrypt.go create mode 100644 scrypt/scrypt_test.go diff --git a/scrypt/scrypt.go b/scrypt/scrypt.go new file mode 100644 index 0000000..d43fbc9 --- /dev/null +++ b/scrypt/scrypt.go @@ -0,0 +1,109 @@ +// 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" (http://www.tarsnap.com/scrypt/scrypt.pdf). +package scrypt + +import ( + "crypto/sha256" + "encoding/binary" + "errors" + + "code.google.com/p/go.crypto/pbkdf2" + "code.google.com/p/go.crypto/salsa20/salsa" +) + +const maxInt = int(^uint(0) >> 1) + +// blockCopy copies n bytes from src into dst. +func blockCopy(dst, src []byte, n int) { + copy(dst, src[:n]) +} + +// blockXOR XORs bytes from dst with n bytes from src. +func blockXOR(dst, src []byte, n int) { + for i, v := range src[:n] { + dst[i] ^= v + } +} + +func blockMix(b, y []byte, r int) { + var x [64]byte + + blockCopy(x[:], b[(2*r-1)*64:], 64) + + for i := 0; i < 2*r*64; i += 64 { + blockXOR(x[:], b[i:], 64) + salsa.Core208(&x, &x) + blockCopy(y[i:], x[:], 64) + } + + for i := 0; i < r; i++ { + blockCopy(b[i*64:], y[i*2*64:], 64) + } + + for i := 0; i < r; i++ { + blockCopy(b[(i+r)*64:], y[(i*2+1)*64:], 64) + } +} + +func integer(b []byte, r int) uint64 { + return binary.LittleEndian.Uint64(b[(2*r-1)*64:]) +} + +func smix(b []byte, r, N int, v, xy []byte) { + x := xy + y := xy[128*r:] + + blockCopy(x, b, 128*r) + + for i := 0; i < N; i++ { + blockCopy(v[i*128*r:], x, 128*r) + blockMix(x, y, r) + } + + for i := 0; i < N; i++ { + j := int(integer(x, r) & uint64(N-1)) + blockXOR(x, v[j*128*r:], 128*r) + blockMix(x, y, r) + } + + blockCopy(b, x, 128*r) +} + +// 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 := 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([]byte, 256*r) + v := make([]byte, 128*r*N) + 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 +} diff --git a/scrypt/scrypt_test.go b/scrypt/scrypt_test.go new file mode 100644 index 0000000..60b73ec --- /dev/null +++ b/scrypt/scrypt_test.go @@ -0,0 +1,112 @@ +// 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 + +import ( + "bytes" + "testing" +) + +type testVector struct { + password string + salt string + N, r, p int + output []byte +} + +var good = []testVector{ + { + "", + "", + 16, 1, 1, + []byte{ + 0x77, 0xd6, 0x57, 0x62, 0x38, 0x65, 0x7b, 0x20, 0x3b, + 0x19, 0xca, 0x42, 0xc1, 0x8a, 0x04, 0x97, 0xf1, 0x6b, + 0x48, 0x44, 0xe3, 0x07, 0x4a, 0xe8, 0xdf, 0xdf, 0xfa, + 0x3f, 0xed, 0xe2, 0x14, 0x42, 0xfc, 0xd0, 0x06, 0x9d, + 0xed, 0x09, 0x48, 0xf8, 0x32, 0x6a, 0x75, 0x3a, 0x0f, + 0xc8, 0x1f, 0x17, 0xe8, 0xd3, 0xe0, 0xfb, 0x2e, 0x0d, + 0x36, 0x28, 0xcf, 0x35, 0xe2, 0x0c, 0x38, 0xd1, 0x89, + 0x06, + }, + }, + { + "password", + "NaCl", + 1024, 8, 16, + []byte{ + 0xfd, 0xba, 0xbe, 0x1c, 0x9d, 0x34, 0x72, 0x00, 0x78, + 0x56, 0xe7, 0x19, 0x0d, 0x01, 0xe9, 0xfe, 0x7c, 0x6a, + 0xd7, 0xcb, 0xc8, 0x23, 0x78, 0x30, 0xe7, 0x73, 0x76, + 0x63, 0x4b, 0x37, 0x31, 0x62, 0x2e, 0xaf, 0x30, 0xd9, + 0x2e, 0x22, 0xa3, 0x88, 0x6f, 0xf1, 0x09, 0x27, 0x9d, + 0x98, 0x30, 0xda, 0xc7, 0x27, 0xaf, 0xb9, 0x4a, 0x83, + 0xee, 0x6d, 0x83, 0x60, 0xcb, 0xdf, 0xa2, 0xcc, 0x06, + 0x40, + }, + }, + { + "pleaseletmein", "SodiumChloride", + 16384, 8, 1, + []byte{ + 0x70, 0x23, 0xbd, 0xcb, 0x3a, 0xfd, 0x73, 0x48, 0x46, + 0x1c, 0x06, 0xcd, 0x81, 0xfd, 0x38, 0xeb, 0xfd, 0xa8, + 0xfb, 0xba, 0x90, 0x4f, 0x8e, 0x3e, 0xa9, 0xb5, 0x43, + 0xf6, 0x54, 0x5d, 0xa1, 0xf2, 0xd5, 0x43, 0x29, 0x55, + 0x61, 0x3f, 0x0f, 0xcf, 0x62, 0xd4, 0x97, 0x05, 0x24, + 0x2a, 0x9a, 0xf9, 0xe6, 0x1e, 0x85, 0xdc, 0x0d, 0x65, + 0x1e, 0x40, 0xdf, 0xcf, 0x01, 0x7b, 0x45, 0x57, 0x58, + 0x87, + }, + }, + /* + // Disabled: needs 1 GiB RAM and takes too long for a simple test. + { + "pleaseletmein", "SodiumChloride", + 1048576, 8, 1, + []byte{ + 0x21, 0x01, 0xcb, 0x9b, 0x6a, 0x51, 0x1a, 0xae, 0xad, + 0xdb, 0xbe, 0x09, 0xcf, 0x70, 0xf8, 0x81, 0xec, 0x56, + 0x8d, 0x57, 0x4a, 0x2f, 0xfd, 0x4d, 0xab, 0xe5, 0xee, + 0x98, 0x20, 0xad, 0xaa, 0x47, 0x8e, 0x56, 0xfd, 0x8f, + 0x4b, 0xa5, 0xd0, 0x9f, 0xfa, 0x1c, 0x6d, 0x92, 0x7c, + 0x40, 0xf4, 0xc3, 0x37, 0x30, 0x40, 0x49, 0xe8, 0xa9, + 0x52, 0xfb, 0xcb, 0xf4, 0x5c, 0x6f, 0xa7, 0x7a, 0x41, + 0xa4, + }, + }, + */ +} + +var bad = []testVector{ + {"p", "s", 0, 1, 1, nil}, // N == 0 + {"p", "s", 1, 1, 1, nil}, // N == 1 + {"p", "s", 7, 8, 1, nil}, // N is not power of 2 + {"p", "s", 16, maxInt / 2, maxInt / 2, nil}, // p * r too large +} + +func TestKey(t *testing.T) { + for i, v := range good { + k, err := Key([]byte(v.password), []byte(v.salt), v.N, v.r, v.p, len(v.output)) + if err != nil { + t.Errorf("%d: got unexpected error: %s", i, err) + } + if !bytes.Equal(k, v.output) { + t.Errorf("%d: expected %x, got %x", i, v.output, k) + } + } + for i, v := range bad { + _, err := Key([]byte(v.password), []byte(v.salt), v.N, v.r, v.p, 32) + if err == nil { + t.Errorf("%d: expected error, got nil", i) + } + } +} + +func BenchmarkKey(b *testing.B) { + for i := 0; i < b.N; i++ { + Key([]byte("password"), []byte("salt"), 16384, 8, 1, 64) + } +}