sign

Documentation

Overview

Package sign can be used to verify messages were signed with a given secret key. The implementation uses the Ed25519 signature algorithm. See https://nacl.cr.yp.to/sign.html.

Example

package main

import (
	"crypto/rand"
	"fmt"
	"log"

	"github.com/kevinburke/nacl/sign"
)

func main() {
	// Create a public and private key pair.
	pubkey, privkey, err := sign.Keypair(rand.Reader)
	if err != nil {
		log.Fatal(err)
	}
	message := []byte("Are you taking notes on a criminal conspiracy?")
	signedMessage := sign.Sign(message, privkey)
	// The first SignatureSize bytes will be the signature. The remaining bytes
	// will be the message.
	fmt.Printf("%s\n", signedMessage[sign.SignatureSize:])
	result := sign.Verify(signedMessage, pubkey)
	fmt.Println(result)
}

Output:

Are you taking notes on a criminal conspiracy?
true

Index

• Constants
• func Keypair(rand io.Reader) (publicKey PublicKey, privateKey PrivateKey, err error)
• func Sign(message []byte, privateKey PrivateKey) []byte
• func Verify(sig []byte, publicKey PublicKey) bool
• type PrivateKey
  • func (priv PrivateKey) Public() crypto.PublicKey
  • func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (signature []byte, err error)
• type PublicKey
  • func (key PublicKey) Verify(signature []byte) bool

Examples

• Package

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
)

Functions

func Keypair

func Keypair(rand io.Reader) (publicKey PublicKey, privateKey PrivateKey, err error)

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

func Sign

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

Sign signs the message with privateKey. The first SignatureSize bytes of the response will be the signature; the rest will be the message. It will panic if len(privateKey) is not PrivateKeySize.

func Verify

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

Verify reports whether sig is a valid signature of message by publicKey. The first SignatureSize bytes of sig are the signature and the remainder is the message. Verify will panic if len(publicKey) is not PublicKeySize.

Types

type PrivateKey

type PrivateKey ed25519.PrivateKey

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

func (PrivateKey) Public

func (priv PrivateKey) Public() crypto.PublicKey

Public returns the PublicKey corresponding to priv.

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 ed25519.PublicKey

PublicKey is the type of Ed25519 public keys.

func (PublicKey) Verify

func (key PublicKey) Verify(signature []byte) bool

Verify uses key to report whether signature is a valid signature of message. The first SignatureSize bytes of signature should be the signature; the remaining bytes are the message to verify.