blake2s

Documentation

Overview

Package blake2s implements the BLAKE2s hash algorithm defined by RFC 7693 and the extendable output function (XOF) BLAKE2Xs.

BLAKE2s is optimized for 8- to 32-bit platforms and produces digests of any size between 1 and 32 bytes. For a detailed specification of BLAKE2s see https://blake2.net/blake2.pdf and for BLAKE2Xs see https://blake2.net/blake2x.pdf

If you aren't sure which function you need, use BLAKE2s (Sum256 or New256). If you need a secret-key MAC (message authentication code), use the New256 function with a non-nil key.

BLAKE2X is a construction to compute hash values larger than 32 bytes. It can produce hash values between 0 and 65535 bytes.

Index

• Constants
• func New128(key []byte) (hash.Hash, error)
• func New256(key []byte) (hash.Hash, error)
• func Sum256(data []byte) [Size]byte
• type XOF
  • func NewXOF(size uint16, key []byte) (XOF, error)

Constants

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
)

const OutputLengthUnknown = 0

OutputLengthUnknown can be used as the size argument to NewXOF to indicate the length of the output is not known in advance.

Functions

func New128

func New128(key []byte) (hash.Hash, error)

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 New256

func New256(key []byte) (hash.Hash, error)

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. When the key is nil, the returned hash.Hash implements BinaryMarshaler and BinaryUnmarshaler for state (de)serialization as documented by hash.Hash.

func Sum256

func Sum256(data []byte) [Size]byte

Sum256 returns the BLAKE2s-256 checksum of the data.

Types

type XOF

type XOF interface {
	// Write absorbs more data into the hash's state. It panics if called
	// after Read.
	io.Writer

	// Read reads more output from the hash. It returns io.EOF if the limit
	// has been reached.
	io.Reader

	// Clone returns a copy of the XOF in its current state.
	Clone() XOF

	// Reset resets the XOF to its initial state.
	Reset()
}

XOF defines the interface to hash functions that support arbitrary-length output.

func NewXOF

func NewXOF(size uint16, key []byte) (XOF, error)

NewXOF creates a new variable-output-length hash. The hash either produce a known number of bytes (1 <= size < 65535), or an unknown number of bytes (size == OutputLengthUnknown). In the latter case, an absolute limit of 128GiB applies.

A non-nil key turns the hash into a MAC. The key must between zero and 32 bytes long.