/usr/share/gocode/src/golang.org/x/crypto/blake2s/blake2s.go is in golang-golang-x-crypto-dev 1:0.0~git20170629.0.5ef0053-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 | // Copyright 2016 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 blake2s implements the BLAKE2s hash algorithm as
// defined in RFC 7693.
package blake2s // import "golang.org/x/crypto/blake2s"
import (
"encoding/binary"
"errors"
"hash"
)
const (
// The blocksize of BLAKE2s in bytes.
BlockSize = 64
// The hash size of BLAKE2s-256 in bytes.
Size = 32
// The hash size of BLAKE2s-128 in bytes.
Size128 = 16
)
var errKeySize = errors.New("blake2s: invalid key size")
var iv = [8]uint32{
0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
}
// Sum256 returns the BLAKE2s-256 checksum of the data.
func Sum256(data []byte) [Size]byte {
var sum [Size]byte
checkSum(&sum, Size, data)
return sum
}
// New256 returns a new hash.Hash computing the BLAKE2s-256 checksum. A non-nil
// key turns the hash into a MAC. The key must between zero and 32 bytes long.
func New256(key []byte) (hash.Hash, error) { return newDigest(Size, key) }
// New128 returns a new hash.Hash computing the BLAKE2s-128 checksum given a
// non-empty key. Note that a 128-bit digest is too small to be secure as a
// cryptographic hash and should only be used as a MAC, thus the key argument
// is not optional.
func New128(key []byte) (hash.Hash, error) {
if len(key) == 0 {
return nil, errors.New("blake2s: a key is required for a 128-bit hash")
}
return newDigest(Size128, key)
}
func newDigest(hashSize int, key []byte) (*digest, error) {
if len(key) > Size {
return nil, errKeySize
}
d := &digest{
size: hashSize,
keyLen: len(key),
}
copy(d.key[:], key)
d.Reset()
return d, nil
}
func checkSum(sum *[Size]byte, hashSize int, data []byte) {
var (
h [8]uint32
c [2]uint32
)
h = iv
h[0] ^= uint32(hashSize) | (1 << 16) | (1 << 24)
if length := len(data); length > BlockSize {
n := length &^ (BlockSize - 1)
if length == n {
n -= BlockSize
}
hashBlocks(&h, &c, 0, data[:n])
data = data[n:]
}
var block [BlockSize]byte
offset := copy(block[:], data)
remaining := uint32(BlockSize - offset)
if c[0] < remaining {
c[1]--
}
c[0] -= remaining
hashBlocks(&h, &c, 0xFFFFFFFF, block[:])
for i, v := range h {
binary.LittleEndian.PutUint32(sum[4*i:], v)
}
}
type digest struct {
h [8]uint32
c [2]uint32
size int
block [BlockSize]byte
offset int
key [BlockSize]byte
keyLen int
}
func (d *digest) BlockSize() int { return BlockSize }
func (d *digest) Size() int { return d.size }
func (d *digest) Reset() {
d.h = iv
d.h[0] ^= uint32(d.size) | (uint32(d.keyLen) << 8) | (1 << 16) | (1 << 24)
d.offset, d.c[0], d.c[1] = 0, 0, 0
if d.keyLen > 0 {
d.block = d.key
d.offset = BlockSize
}
}
func (d *digest) Write(p []byte) (n int, err error) {
n = len(p)
if d.offset > 0 {
remaining := BlockSize - d.offset
if n <= remaining {
d.offset += copy(d.block[d.offset:], p)
return
}
copy(d.block[d.offset:], p[:remaining])
hashBlocks(&d.h, &d.c, 0, d.block[:])
d.offset = 0
p = p[remaining:]
}
if length := len(p); length > BlockSize {
nn := length &^ (BlockSize - 1)
if length == nn {
nn -= BlockSize
}
hashBlocks(&d.h, &d.c, 0, p[:nn])
p = p[nn:]
}
d.offset += copy(d.block[:], p)
return
}
func (d *digest) Sum(b []byte) []byte {
var block [BlockSize]byte
h := d.h
c := d.c
copy(block[:], d.block[:d.offset])
remaining := uint32(BlockSize - d.offset)
if c[0] < remaining {
c[1]--
}
c[0] -= remaining
hashBlocks(&h, &c, 0xFFFFFFFF, block[:])
var sum [Size]byte
for i, v := range h {
binary.LittleEndian.PutUint32(sum[4*i:], v)
}
return append(b, sum[:d.size]...)
}
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