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Andreas Auernhammer 625c6a7b44 argon2: add new package implementing the Argon2 PBKDF family
This CL adds the package argon2. The argon2 package implements
the Argon2 PBKDF family (Argon2i, Argon2d, Argon2id).

Argon2 is memory-hard key derivation function and is specified
at https://github.com/P-H-C/phc-winner-argon2/blob/master/argon2-specs.pdf
It can be used to derive cryptographic keys with high entropy from low
entropy passwords.

Fixes golang/go#19896

Change-Id: I5b099682a8e3d7569ad18400cebddefc99a7e22f
Reviewed-on: https://go-review.googlesource.com/82575
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
2017-12-18 18:31:08 +00:00

54 lines
1.1 KiB
Go

// Copyright 2017 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 argon2
import (
"encoding/binary"
"hash"
"golang.org/x/crypto/blake2b"
)
// blake2bHash computes an arbitrary long hash value of in
// and writes the hash to out.
func blake2bHash(out []byte, in []byte) {
var b2 hash.Hash
if n := len(out); n < blake2b.Size {
b2, _ = blake2b.New(n, nil)
} else {
b2, _ = blake2b.New512(nil)
}
var buffer [blake2b.Size]byte
binary.LittleEndian.PutUint32(buffer[:4], uint32(len(out)))
b2.Write(buffer[:4])
b2.Write(in)
if len(out) <= blake2b.Size {
b2.Sum(out[:0])
return
}
outLen := len(out)
b2.Sum(buffer[:0])
b2.Reset()
copy(out, buffer[:32])
out = out[32:]
for len(out) > blake2b.Size {
b2.Write(buffer[:])
b2.Sum(buffer[:0])
copy(out, buffer[:32])
out = out[32:]
b2.Reset()
}
if outLen%blake2b.Size > 0 { // outLen > 64
r := ((outLen + 31) / 32) - 2 // ⌈τ /32⌉-2
b2, _ = blake2b.New(outLen-32*r, nil)
}
b2.Write(buffer[:])
b2.Sum(out[:0])
}