How to Encrypt and Decrypt Text Strings with JavaScript

In one of my web projects, I required a simple encryption and decryption JavaScript library that could encode a piece of text and and then decode the encoded string on the server side.

The easiest option is the base64 encoding scheme that can be easily implemented in both native JavaScript and Google Apps Script.

Base64 Encoding with Google Apps Script

const base64Encode = text => {
  const base64data = Utilities.base64Encode(text, Utilities.Charset.UTF_8);
  return base64data;
};

const base64Decode = base64data => {
  const decoded = Utilities.base64Decode(base64data, Utilities.Charset.UTF_8);
  const input = Utilities.newBlob(decoded).getDataAsString();
  return input;
};

Base64 Encoding with JavaScript

const CryptoJS = require('crypto-js');

const encrypt = text => {
  return CryptoJS.enc.Base64.stringify(CryptoJS.enc.Utf8.parse(text));
};

const decrypt = data => {
  return CryptoJS.enc.Base64.parse(data).toString(CryptoJS.enc.Utf8);
};

The obvious downside is that Base64 is encoding (not encryption) and the Base64 strings can be easily decoded.

If you are looking for a secure encryption algorithm that would require a secret passphrase for decrypting the encrypted text, go with AES. It generates longer strings but they cannot be decrypted without the password.

AES Plain Text Encryption & Decryption

const CryptoJS = require('crypto-js');

const encryptWithAES = text => {
  const passphrase = '123';
  return CryptoJS.AES.encrypt(text, passphrase).toString();
};

const decryptWithAES = ciphertext => {
  const passphrase = '123';
  const bytes = CryptoJS.AES.decrypt(ciphertext, passphrase);
  const originalText = bytes.toString(CryptoJS.enc.Utf8);
  return originalText;
};

AES Encrypt & Decryption with Google Apps Script

If you would like to use AES encryption algorithm with Google Apps Script, use the Apps Script Starter to import the CryptoJS package in your project as shown in this example.

import AES from 'crypto-js/aes';
import Utf8 from 'crypto-js/enc-utf8';

const encryptWithAES = (text, passphrase) => {
  return AES.encrypt(text, passphrase).toString();
};

const decryptWithAES = (ciphertext, passphrase) => {
  const bytes = AES.decrypt(ciphertext, passphrase);
  const originalText = bytes.toString(Utf8);
  return originalText;
};

global.testAES = () => {
  const inputText = 'Hello World';
  const passphrase = 'My Secret Passphrase';

  Logger.log({ inputText });

  const encryptedText = encryptWithAES(inputText, passphrase);
  Logger.log({ encryptedText });

  const decryptedText = decryptWithAES(encryptedText, passphrase);
  Logger.log({ decryptedText });
};

Alternatively, for Google Apps Script, the cCryptoGS library can also be used to implement AES encryption in your projects and Suite add-ons. To get started, go to Resources -> Libraries and add the MSJnPeIon6nzdLewGV60xWqi_d-phDA33 library to your Google Script project.

const encryptedMessage = cCryptoGS.CryptoJS.AES.encrypt('message', 'passphrase').toString();
Logger.log(encryptedMessage);

const decryptedMessage = cCryptoGS.CryptoJS.AES.decrypt(encryptedMessage, 'passphrase').toString(
  CryptoJS.enc.Utf8
);
Logger.log(decryptedMessage);