blake3

README

blake3

go get lukechampine.com/blake3

blake3 implements the BLAKE3 cryptographic hash function.

This implementation is a port of the Rust reference implementation, refactored into more idiomatic Go style and with a handful of performance tweaks. Performance is not great, not terrible. Eventually an assembly-optimized implementation will be merged into x/crypto, and then you should switch to that. In the meantime, you can use this package for code that needs BLAKE3 compatibility and doesn't need to be blazing fast.

Documentation

Overview

Package blake3 implements the BLAKE3 cryptographic hash function.

Index

• func DeriveKey(subKey []byte, ctx string, srcKey []byte)
• func Sum256(b []byte) (out [32]byte)
• func Sum512(b []byte) (out [64]byte)
• type Hasher
  • func New(size int, key []byte) *Hasher
  • func (h *Hasher) BlockSize() int
  • func (h *Hasher) Reset()
  • func (h *Hasher) Size() int
  • func (h *Hasher) Sum(b []byte) (sum []byte)
  • func (h *Hasher) Write(p []byte) (int, error)
  • func (h *Hasher) XOF() *OutputReader
• type OutputReader
  • func (or *OutputReader) Read(p []byte) (int, error)
  • func (or *OutputReader) Seek(offset int64, whence int) (int64, error)

Functions

func DeriveKey

func DeriveKey(subKey []byte, ctx string, srcKey []byte)

DeriveKey derives a subkey from ctx and srcKey. ctx should be hardcoded, globally unique, and application-specific. A good format for ctx strings is:

[application] [commit timestamp] [purpose]

e.g.:

example.com 2019-12-25 16:18:03 session tokens v1

The purpose of these requirements is to ensure that an attacker cannot trick two different applications into using the same context string.

func Sum256

func Sum256(b []byte) (out [32]byte)

Sum256 returns the unkeyed BLAKE3 hash of b, truncated to 256 bits.

func Sum512

func Sum512(b []byte) (out [64]byte)

Sum512 returns the unkeyed BLAKE3 hash of b, truncated to 512 bits.

Types

type Hasher

type Hasher struct {
	// contains filtered or unexported fields
}

Hasher implements hash.Hash.

func New

func New(size int, key []byte) *Hasher

New returns a Hasher for the specified size and key. If key is nil, the hash is unkeyed.

func (*Hasher) BlockSize

func (h *Hasher) BlockSize() int

BlockSize implements hash.Hash.

func (*Hasher) Reset

func (h *Hasher) Reset()

Reset implements hash.Hash.

func (*Hasher) Size

func (h *Hasher) Size() int

Size implements hash.Hash.

func (*Hasher) Sum

func (h *Hasher) Sum(b []byte) (sum []byte)

Sum implements hash.Hash.

func (*Hasher) Write

func (h *Hasher) Write(p []byte) (int, error)

Write implements hash.Hash.

func (*Hasher) XOF

func (h *Hasher) XOF() *OutputReader

XOF returns an OutputReader initialized with the current hash state.

type OutputReader

type OutputReader struct {
	// contains filtered or unexported fields
}

An OutputReader produces an seekable stream of 2^64 - 1 pseudorandom output bytes.

func (*OutputReader) Read

func (or *OutputReader) Read(p []byte) (int, error)

Read implements io.Reader. Callers may assume that Read returns len(p), nil unless the read would extend beyond the end of the stream.

func (*OutputReader) Seek

func (or *OutputReader) Seek(offset int64, whence int) (int64, error)

Seek implements io.Seeker.