Crypto.jsx

import { secretbox, box, randomBytes } from "tweetnacl";
import {
  decodeUTF8,
  encodeUTF8,
  encodeBase64,
  decodeBase64
} from "tweetnacl-util";

const fixedNonce = () => new Uint8Array([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1])//randomBytes(secretbox.nonceLength); 
const newNonce = () => randomBytes(secretbox.nonceLength);

export const generateKey = () => encodeBase64(randomBytes(secretbox.keyLength));

export const encrypt = (keyUint8Array, msg) => {
  const nonce = newNonce();
  console.log("NONCE", nonce)
  const messageUint8 = decodeUTF8(msg);
  const box = secretbox(messageUint8, nonce, keyUint8Array);

  const fullMessage = new Uint8Array(nonce.length + box.length);
  fullMessage.set(nonce);
  fullMessage.set(box, nonce.length);
  console.log("fullMessage", fullMessage)
  const base64FullMessage = encodeBase64(fullMessage);
  return base64FullMessage;
};

export const decrypt = (keyUint8Array, messageWithNonce) => {
  const messageWithNonceAsUint8Array = decodeBase64(messageWithNonce);
  const nonce = messageWithNonceAsUint8Array.slice(0, secretbox.nonceLength);
  const message = messageWithNonceAsUint8Array.slice(
    secretbox.nonceLength,
    messageWithNonce.length
  );

  const decrypted = secretbox.open(message, nonce, keyUint8Array);

  if (!decrypted) {
    throw new Error("Could not decrypt message");
  }

  return encodeUTF8(decrypted);
};

export const buildSharedKey = (pub, priv) => box.before(pub, priv)

/*
const obj = { hello: 'world' };
const pairA = generateKeyPair();
const pairB = generateKeyPair();
const sharedA = box.before(pairB.publicKey, pairA.secretKey);
const sharedB = box.before(pairA.publicKey, pairB.secretKey);
const encrypted = encrypt(sharedA, obj);
const decrypted = decrypt(sharedB, encrypted);
console.log(obj, encrypted, decrypted);*/