kx_example.go

package main

import (
	b64 "encoding/base64"
	"fmt"

	"github.com/GoKillers/libsodium-go/cryptobox"
)

func main() {
	// [server] Generate key pair
	serverSk, serverPk, _ := cryptobox.CryptoBoxKeyPair()

	// [mobile] Generate key pair
	clientSk, clientPk, _ := cryptobox.CryptoBoxKeyPair()

	// [mobile] Send clientPk to server
	// [server] Send serverPk to client
	
	// [server] Calculate shared key
	sharedKeyServer, _ := cryptobox.CryptoBoxBeforeNm(clientPk, serverSk)
	sharedKeyServerB64 := b64.StdEncoding.EncodeToString(sharedKeyServer)

	// [mobile] Calculate shared key
	sharedKeyClient, _ := cryptobox.CryptoBoxBeforeNm(serverPk, clientSk)
	sharedKeyClientB64 := b64.StdEncoding.EncodeToString(sharedKeyClient)

	// Check that shareKey in mobile and server must be equal
	if sharedKeyServerB64 != sharedKeyClientB64 {
		panic("Key exchange fail")
	}

	fmt.Println("Server Shared Key: " + sharedKeyServerB64)
	fmt.Println("Mobile Shared Key: " + sharedKeyClientB64)
	
	// To encrypt and decrypt, the CryptoBoxAfterNm() and CryptoBoxOpenAfterNm() functions can be used
	// Please see: https://github.com/GoKillers/libsodium-go/blob/master/cryptobox/crypto_box.go#L111-L137
}