vendor golang.org/x/crypto using glide

This would help us build go-mtree on RHEL/CentOS and
distros where golang.org/x/crypto isn't provided or supported.

Signed-off-by: Lokesh Mandvekar <lsm5@fedoraproject.org>

vendor/golang.org/x/crypto/blake2s/blake2s.go

@@ -0,0 +1,160 @@
+// 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 (
+	"encoding/binary"
+	"errors"
+	"hash"
+)
+
+const (
+	// The blocksize of BLAKE2s in bytes.
+	BlockSize = 64
+	// The hash size of BLAKE2s-256 in bytes.
+	Size = 32
+)
+
+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) }
+
+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]...)
+}