# README

ChaCha20Guard

A pure Go implementation of ChaCha20 and its extended nonce variant XChaCha20 with MemGuard in order to protect the key in memory.

Before using read the Warning

The implementation is based on https://github.com/codahale/chacha20

Download/Install

go get -u github.com/alexzava/chacha20guard

Usage

Import

import (
	"log"
	"crypto/rand"

	"github.com/awnumar/memguard"
	"github.com/alexzava/chacha20guard"
)

ChaCha20

message := []byte("Hello World!")

//Generate random nonce
nonce := make([]byte, 8)
_, err := rand.Read(nonce)
if err != nil {
	log.Fatal(err)
}

//Generate random key with memguard
key, err := memguard.NewImmutableRandom(32)
if err != nil {
	log.Println(err)
	memguard.SafeExit(1)
}
defer key.Destroy()

c, err := chacha20guard.New(key, nonce)
if err != nil {
	log.Fatal(err)
}

ciphertext := make([]byte, len(message))
c.XORKeyStream(ciphertext, message)

XChaCha20

message := []byte("Hello World!")

//Generate random nonce
nonce := make([]byte, 24)
_, err := rand.Read(nonce)
if err != nil {
	log.Fatal(err)
}

//Generate random key with memguard
key, err := memguard.NewImmutableRandom(32)
if err != nil {
	log.Println(err)
	memguard.SafeExit(1)
}
defer key.Destroy()

c, err := chacha20guard.NewX(key, nonce)
if err != nil {
	log.Fatal(err)
}

ciphertext := make([]byte, len(message))
c.XORKeyStream(ciphertext, message)