crypto.js

//encrypt
const encrypt = (salt, text) => {
  const textToChars = (text) => text.split("").map((c) => c.charCodeAt(0));
  const byteHex = (n) => ("0" + Number(n).toString(16)).substr(-2);
  const applySaltToChar = (code) => textToChars(salt).reduce((a, b) => a ^ b, code);

  return text
    .split("")
    .map(textToChars)
    .map(applySaltToChar)
    .map(byteHex)
    .join("");
};


//decrypt
const decrypt = (salt, encoded) => {
  const textToChars = (text) => text.split("").map((c) => c.charCodeAt(0));
  const applySaltToChar = (code) => textToChars(salt).reduce((a, b) => a ^ b, code);
  return encoded
    .match(/.{1,2}/g)
    .map((hex) => parseInt(hex, 16))
    .map(applySaltToChar)
    .map((charCode) => String.fromCharCode(charCode))
    .join("");
};

// encrypting
console.log(encrypt('salt', 'quick brown fox')); // -> 7b7f6369612a6878657d642a6c6572

// decrypting
console.log(decrypt('salt', '7b7f6369612a6878657d642a6c6572')); // -> quick brown fox