var secretMessage = "Hello World!";

// Encrypt our secret message.
var encrypted = CryptoJS.AES.encrypt(secretMessage, "Secret Passphrase");

// Decrypt our message.
var decrypted = CryptoJS.AES.decrypt(encrypted, "Secret Passphrase");

// Since the decrypted message is a Base64 string, to read the message we first need to convert it.
var message = decrypted.toString(CryptoJS.enc.Utf8); // Hello World!