Files
crypto/sha3/shake.go
T
David Leon Gil 1b32d8b50a go.crypto/sha3: update to sync with draft FIPS-202
1. API:

This exposes a minimal API: the SHA-3 functions implement hash.Hash. The
SHAKE functions implement a new "ShakeHash" interface that implements
io.Reader, io.Writer, and Reset().

(The previous Barrier() function has been removed.)

(Alternative proposal: Don't implement io.Reader, but instead provide a
"Digest(d []byte) error" function that performs a hash.Hash style copy.
Somewhat more minimal, but very easy to use incorrectly.)

2. Tests

Added the complete set of ShortMsgKATs from
   https://github.com/gvanas/KeccakCodePackage

3. Correctness

In sync with draft FIPS-202.

4. Documentation

A summary of the security properties of the SHA-3 and SHAKE functions is
provided in doc.go; some concrete recommendations as well.

Fixes 8563.

R=golang-codereviews, agl
CC=golang-codereviews
https://golang.org/cl/130950043
2014-09-03 12:04:00 -07:00

61 lines
1.8 KiB
Go

// Copyright 2014 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 sha3
// This file defines the ShakeHash interface, and provides
// functions for creating SHAKE instances, as well as utility
// functions for hashing bytes to arbitrary-length output.
import (
"io"
)
// ShakeHash defines the interface to hash functions that
// support arbitrary-length output.
type ShakeHash interface {
// Write absorbs more data into the hash's state. It panics if input is
// written to it after output has been read from it.
io.Writer
// Read reads more output from the hash; reading affects the hash's
// state. (ShakeHash.Read is thus very different from Hash.Sum)
// It never returns an error.
io.Reader
// Clone returns a copy of the ShakeHash in its current state.
Clone() ShakeHash
// Reset resets the ShakeHash to its initial state.
Reset()
}
func (d *state) Clone() ShakeHash {
return d.clone()
}
// NewShake128 creates a new SHAKE128 variable-output-length ShakeHash.
// Its generic security strength is 128 bits against all attacks if at
// least 32 bytes of its output are used.
func NewShake128() ShakeHash { return &state{rate: 168, dsbyte: 0x1f} }
// NewShake256 creates a new SHAKE128 variable-output-length ShakeHash.
// Its generic security strength is 256 bits against all attacks if
// at least 64 bytes of its output are used.
func NewShake256() ShakeHash { return &state{rate: 136, dsbyte: 0x1f} }
// ShakeSum128 writes an arbitrary-length digest of data into hash.
func ShakeSum128(hash, data []byte) {
h := NewShake128()
h.Write(data)
h.Read(hash)
}
// ShakeSum256 writes an arbitrary-length digest of data into hash.
func ShakeSum256(hash, data []byte) {
h := NewShake256()
h.Write(data)
h.Read(hash)
}