eitherbox

README

eitherbox

A NaCL based secret box that can be opened with either of two keys.

Example:

package main

import (
	"crypto/rand"
	"fmt"

	"github.com/mrobinsn/eitherbox"
	"golang.org/x/crypto/nacl/box"
)

func main() {
	// Create keys for Alice
	alicePublic, alicePrivate, _ := box.GenerateKey(rand.Reader)

	// Create keys for Bob
	bobPublic, bobPrivate, _ := box.GenerateKey(rand.Reader)

	// Create keys for Eve
	evePublic, evePrivate, _ := box.GenerateKey(rand.Reader)

	secret := []byte("hello world")

	ebox := eitherbox.Encrypt(secret, alicePublic, bobPublic)

	// Alice can decrypt
	aliceMsg, _ := ebox.Decrypt(alicePublic, alicePrivate)

	// Bob can decrypt
	bobMsg, _ := ebox.Decrypt(bobPublic, bobPrivate)

	// Eve can't decrypt
	eveMsg, _ := ebox.Decrypt(evePublic, evePrivate)

	fmt.Println("Alice got:", string(aliceMsg))
	fmt.Println("Bob got:", string(bobMsg))
	fmt.Println("Eve got:", string(eveMsg))
	// Output: Alice got: hello world
	// Bob got: hello world
	// Eve got:
}

Documentation

Overview

Package eitherbox provides a cryptographically secure composition of NaCL secretbox that can be opened by either of two key holders.

Index

• type Box
  • func Encrypt(b []byte, k1, k2 Key) Box
  • func (b Box) Decrypt(pub, prv Key) ([]byte, error)
• type Key

Examples

• Encrypt

Types

type Box

type Box []byte

Box is a cryptographically secure box that can be opened with one of two keys.

func Encrypt

func Encrypt(b []byte, k1, k2 Key) Box

Encrypt encrypts `b` into a package that can be decrypted by either public key. Public/private keypairs should be generated with box.GenerateKey(..).

Example

// Create keys for Alice
alicePublic, alicePrivate, _ := box.GenerateKey(rand.Reader)

// Create keys for Bob
bobPublic, bobPrivate, _ := box.GenerateKey(rand.Reader)

// Create keys for Eve
evePublic, evePrivate, _ := box.GenerateKey(rand.Reader)

secret := []byte("hello world")

twokeyBox := Encrypt(secret, alicePublic, bobPublic)

// Alice can decrypt
aliceMsg, _ := twokeyBox.Decrypt(alicePublic, alicePrivate)

// Bob can decrypt
bobMsg, _ := twokeyBox.Decrypt(bobPublic, bobPrivate)

// Eve can't decrypt
eveMsg, _ := twokeyBox.Decrypt(evePublic, evePrivate)

fmt.Println("Alice got:", string(aliceMsg))
fmt.Println("Bob got:", string(bobMsg))
fmt.Println("Eve got:", string(eveMsg))

Output:

Alice got: hello world
Bob got: hello world
Eve got:

func (Box) Decrypt

func (b Box) Decrypt(pub, prv Key) ([]byte, error)

Decrypt returns the original plaintext, given that this key is one of the original two keys used to create the box.

type Key

type Key *[32]byte

Key represents a NaCL compatible key