gtsocial-umbx

blake2b.go (7503B)

---

 // 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 blake2b implements the BLAKE2b hash algorithm defined by RFC 7693
 // and the extendable output function (XOF) BLAKE2Xb.
 //
 // BLAKE2b is optimized for 64-bit platforms—including NEON-enabled ARMs—and
 // produces digests of any size between 1 and 64 bytes.
 // For a detailed specification of BLAKE2b see https://blake2.net/blake2.pdf
 // and for BLAKE2Xb see https://blake2.net/blake2x.pdf
 //
 // If you aren't sure which function you need, use BLAKE2b (Sum512 or New512).
 // If you need a secret-key MAC (message authentication code), use the New512
 // function with a non-nil key.
 //
 // BLAKE2X is a construction to compute hash values larger than 64 bytes. It
 // can produce hash values between 0 and 4 GiB.
 package blake2b
 
 import (
 	"encoding/binary"
 	"errors"
 	"hash"
 )
 
 const (
 	// The blocksize of BLAKE2b in bytes.
 	BlockSize = 128
 	// The hash size of BLAKE2b-512 in bytes.
 	Size = 64
 	// The hash size of BLAKE2b-384 in bytes.
 	Size384 = 48
 	// The hash size of BLAKE2b-256 in bytes.
 	Size256 = 32
 )
 
 var (
 	useAVX2 bool
 	useAVX  bool
 	useSSE4 bool
 )
 
 var (
 	errKeySize  = errors.New("blake2b: invalid key size")
 	errHashSize = errors.New("blake2b: invalid hash size")
 )
 
 var iv = [8]uint64{
 	0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1,
 	0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179,
 }
 
 // Sum512 returns the BLAKE2b-512 checksum of the data.
 func Sum512(data []byte) [Size]byte {
 	var sum [Size]byte
 	checkSum(&sum, Size, data)
 	return sum
 }
 
 // Sum384 returns the BLAKE2b-384 checksum of the data.
 func Sum384(data []byte) [Size384]byte {
 	var sum [Size]byte
 	var sum384 [Size384]byte
 	checkSum(&sum, Size384, data)
 	copy(sum384[:], sum[:Size384])
 	return sum384
 }
 
 // Sum256 returns the BLAKE2b-256 checksum of the data.
 func Sum256(data []byte) [Size256]byte {
 	var sum [Size]byte
 	var sum256 [Size256]byte
 	checkSum(&sum, Size256, data)
 	copy(sum256[:], sum[:Size256])
 	return sum256
 }
 
 // New512 returns a new hash.Hash computing the BLAKE2b-512 checksum. A non-nil
 // key turns the hash into a MAC. The key must be between zero and 64 bytes long.
 func New512(key []byte) (hash.Hash, error) { return newDigest(Size, key) }
 
 // New384 returns a new hash.Hash computing the BLAKE2b-384 checksum. A non-nil
 // key turns the hash into a MAC. The key must be between zero and 64 bytes long.
 func New384(key []byte) (hash.Hash, error) { return newDigest(Size384, key) }
 
 // New256 returns a new hash.Hash computing the BLAKE2b-256 checksum. A non-nil
 // key turns the hash into a MAC. The key must be between zero and 64 bytes long.
 func New256(key []byte) (hash.Hash, error) { return newDigest(Size256, key) }
 
 // New returns a new hash.Hash computing the BLAKE2b checksum with a custom length.
 // A non-nil key turns the hash into a MAC. The key must be between zero and 64 bytes long.
 // The hash size can be a value between 1 and 64 but it is highly recommended to use
 // values equal or greater than:
 // - 32 if BLAKE2b is used as a hash function (The key is zero bytes long).
 // - 16 if BLAKE2b is used as a MAC function (The key is at least 16 bytes long).
 // When the key is nil, the returned hash.Hash implements BinaryMarshaler
 // and BinaryUnmarshaler for state (de)serialization as documented by hash.Hash.
 func New(size int, key []byte) (hash.Hash, error) { return newDigest(size, key) }
 
 func newDigest(hashSize int, key []byte) (*digest, error) {
 	if hashSize < 1 || hashSize > Size {
 		return nil, errHashSize
 	}
 	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) {
 	h := iv
 	h[0] ^= uint64(hashSize) | (1 << 16) | (1 << 24)
 	var c [2]uint64
 
 	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 := uint64(BlockSize - offset)
 	if c[0] < remaining {
 		c[1]--
 	}
 	c[0] -= remaining
 
 	hashBlocks(&h, &c, 0xFFFFFFFFFFFFFFFF, block[:])
 
 	for i, v := range h[:(hashSize+7)/8] {
 		binary.LittleEndian.PutUint64(sum[8*i:], v)
 	}
 }
 
 type digest struct {
 	h      [8]uint64
 	c      [2]uint64
 	size   int
 	block  [BlockSize]byte
 	offset int
 
 	key    [BlockSize]byte
 	keyLen int
 }
 
 const (
 	magic         = "b2b"
 	marshaledSize = len(magic) + 8*8 + 2*8 + 1 + BlockSize + 1
 )
 
 func (d *digest) MarshalBinary() ([]byte, error) {
 	if d.keyLen != 0 {
 		return nil, errors.New("crypto/blake2b: cannot marshal MACs")
 	}
 	b := make([]byte, 0, marshaledSize)
 	b = append(b, magic...)
 	for i := 0; i < 8; i++ {
 		b = appendUint64(b, d.h[i])
 	}
 	b = appendUint64(b, d.c[0])
 	b = appendUint64(b, d.c[1])
 	// Maximum value for size is 64
 	b = append(b, byte(d.size))
 	b = append(b, d.block[:]...)
 	b = append(b, byte(d.offset))
 	return b, nil
 }
 
 func (d *digest) UnmarshalBinary(b []byte) error {
 	if len(b) < len(magic) || string(b[:len(magic)]) != magic {
 		return errors.New("crypto/blake2b: invalid hash state identifier")
 	}
 	if len(b) != marshaledSize {
 		return errors.New("crypto/blake2b: invalid hash state size")
 	}
 	b = b[len(magic):]
 	for i := 0; i < 8; i++ {
 		b, d.h[i] = consumeUint64(b)
 	}
 	b, d.c[0] = consumeUint64(b)
 	b, d.c[1] = consumeUint64(b)
 	d.size = int(b[0])
 	b = b[1:]
 	copy(d.block[:], b[:BlockSize])
 	b = b[BlockSize:]
 	d.offset = int(b[0])
 	return nil
 }
 
 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] ^= uint64(d.size) | (uint64(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:]
 	}
 
 	if len(p) > 0 {
 		d.offset += copy(d.block[:], p)
 	}
 
 	return
 }
 
 func (d *digest) Sum(sum []byte) []byte {
 	var hash [Size]byte
 	d.finalize(&hash)
 	return append(sum, hash[:d.size]...)
 }
 
 func (d *digest) finalize(hash *[Size]byte) {
 	var block [BlockSize]byte
 	copy(block[:], d.block[:d.offset])
 	remaining := uint64(BlockSize - d.offset)
 
 	c := d.c
 	if c[0] < remaining {
 		c[1]--
 	}
 	c[0] -= remaining
 
 	h := d.h
 	hashBlocks(&h, &c, 0xFFFFFFFFFFFFFFFF, block[:])
 
 	for i, v := range h {
 		binary.LittleEndian.PutUint64(hash[8*i:], v)
 	}
 }
 
 func appendUint64(b []byte, x uint64) []byte {
 	var a [8]byte
 	binary.BigEndian.PutUint64(a[:], x)
 	return append(b, a[:]...)
 }
 
 func appendUint32(b []byte, x uint32) []byte {
 	var a [4]byte
 	binary.BigEndian.PutUint32(a[:], x)
 	return append(b, a[:]...)
 }
 
 func consumeUint64(b []byte) ([]byte, uint64) {
 	x := binary.BigEndian.Uint64(b)
 	return b[8:], x
 }
 
 func consumeUint32(b []byte) ([]byte, uint32) {
 	x := binary.BigEndian.Uint32(b)
 	return b[4:], x
 }