Longbottom's Locker.js

    document.getElementById('neville-locker-form').addEventListener('submit', function(e) {
        e.preventDefault();

        var passphrase = document.getElementById('passwd').value,
            encryptedMsg = '4cce4470203e10b395ab1787a22553a5b2503d42a965da813676d929cc16f76cU2FsdGVkX19FvUyhqWoQKHXNLBL64g8acK4UQoP6XZQ/n4MRL3rgQj8TJ/3r8Awtxte2V9s+RLfQHJOHGwYtctqRa/H2BetmxjwGG+LYKUWC8Z6WBoYbecwtATCOuwewnp+VKBzsWLme+3BZyRgKEA==',
            encryptedHMAC = encryptedMsg.substring(0, 64),
            encryptedHTML = encryptedMsg.substring(64),
            decryptedHMAC = CryptoJS.HmacSHA256(encryptedHTML, CryptoJS.SHA256(passphrase).toString()).toString();

        if (decryptedHMAC !== encryptedHMAC) {
            alert('Bad passphrase!');
            return;
        }

        var plainHTML = CryptoJS.AES.decrypt(encryptedHTML, passphrase).toString(CryptoJS.enc.Utf8);

        document.write(plainHTML);
        document.close();
    });