ed25519

Documentation

Overview

Package ed25519 implements the Ed25519 signature algorithm. See https://ed25519.cr.yp.to/.

These functions are also compatible with the “Ed25519” function defined in RFC 8032. However, unlike RFC 8032's formulation, this package's private key representation includes a public key suffix to make multiple signing operations with the same key more efficient. This package refers to the RFC 8032 private key as the “seed”.

Index

• Constants
• func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error)
• func Sign(privateKey PrivateKey, message []byte) []byte
• func Sign2(privateKey PrivateKey, message []byte) []byte
• func Verify(publicKey PublicKey, message, sig []byte) bool
• func Verify2(publicKey PublicKey, message, sig []byte) bool
• type PrivateKey
  • func NewDerivedKeyFromSeed(seed []byte, index uint64, salt []byte) PrivateKey
  • func NewKeyFromSeed(seed []byte) PrivateKey
  • func (priv PrivateKey) Public() crypto.PublicKey
  • func (priv PrivateKey) Seed() []byte
  • func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (signature []byte, err error)
• type PublicKey
  • func ExtractPublicKey(message, sig []byte) (PublicKey, error)

Constants

const (
	// PublicKeySize is the size, in bytes, of public keys as used in this package.
	PublicKeySize = 32
	// PrivateKeySize is the size, in bytes, of private keys as used in this package.
	PrivateKeySize = 64
	// SignatureSize is the size, in bytes, of signatures generated and verified by this package.
	SignatureSize = 64
	// SeedSize is the size, in bytes, of private key seeds. These are the private key representations used by RFC 8032.
	SeedSize = 32
)

Functions

func GenerateKey

func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error)

GenerateKey generates a public/private key pair using entropy from rand. If rand is nil, crypto/rand.Reader will be used.

func Sign

func Sign(privateKey PrivateKey, message []byte) []byte

Sign signs the message with privateKey and returns a signature. It will panic if len(privateKey) is not PrivateKeySize.

func Sign2

func Sign2(privateKey PrivateKey, message []byte) []byte

Sign2 signs the message with privateKey and returns a signature. The signature may be verified using Verify2(), if the signer's public key is known. The signature returned by this method can be used together with the message to extract the public key using ExtractPublicKey() It will panic if len(privateKey) is not PrivateKeySize.

func Verify

func Verify(publicKey PublicKey, message, sig []byte) bool

Verify reports whether sig is a valid signature of message by publicKey. It will panic if len(publicKey) is not PublicKeySize.

func Verify2

func Verify2(publicKey PublicKey, message, sig []byte) bool

Verify2 verifies a signature created with Sign2(), assuming the verifier possesses the public key.

Types

type PrivateKey

type PrivateKey []byte

PrivateKey is the type of Ed25519 private keys. It implements crypto.Signer.

func NewDerivedKeyFromSeed

func NewDerivedKeyFromSeed(seed []byte, index uint64, salt []byte) PrivateKey

NewDerivedKeyFromSeed calculates a private key from a 32 bytes random seed, an integer index and salt

func NewKeyFromSeed

func NewKeyFromSeed(seed []byte) PrivateKey

NewKeyFromSeed calculates a private key from a seed. It will panic if len(seed) is not SeedSize. This function is provided for interoperability with RFC 8032. RFC 8032's private keys correspond to seeds in this package.

func (PrivateKey) Public

func (priv PrivateKey) Public() crypto.PublicKey

Public returns the PublicKey corresponding to priv.

func (PrivateKey) Seed

func (priv PrivateKey) Seed() []byte

Seed returns the private key seed corresponding to priv. It is provided for interoperability with RFC 8032. RFC 8032's private keys correspond to seeds in this package.

func (PrivateKey) Sign

func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (signature []byte, err error)

Sign signs the given message with priv. Ed25519 performs two passes over messages to be signed and therefore cannot handle pre-hashed messages. Thus opts.HashFunc() must return zero to indicate the message hasn't been hashed. This can be achieved by passing crypto.Hash(0) as the value for opts.

type PublicKey

type PublicKey []byte

PublicKey is the type of Ed25519 public keys.

func ExtractPublicKey

func ExtractPublicKey(message, sig []byte) (PublicKey, error)

ExtractPublicKey extracts the signer's public key given a message and its signature. Note that signature must be created using Sign2() and NOT using Sign(). It will panic if len(sig) is not SignatureSize.