Converting Java's PBEWithMD5AndDES to JavaScri

问题:

I'm trying to replicate the Java code in JavaScript. below is my Java code:

public static String encrypt(String input)
final byte[] SALT= { (byte) 0x21, (byte) 0x21, (byte) 0xF0, (byte) 0x55, (byte) 0xC3, (byte) 0x9F, (byte) 0x5A, (byte) 0x75                     };
final int   ITERATION_COUNT = 31;
{
    if (input == null)
    {
        throw new IllegalArgumentException();
    }
    try
    {

        KeySpec keySpec = new PBEKeySpec(null, SALT, ITERATION_COUNT);
        AlgorithmParameterSpec paramSpec = new PBEParameterSpec(SALT, ITERATION_COUNT);

        SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);

        Cipher ecipher = Cipher.getInstance(key.getAlgorithm());
        ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

        byte[] enc = ecipher.doFinal(input.getBytes());

        String res = new String(Base64.encodeBase64(enc));
        // escapes for url
        res = res.replace('+', '-').replace('/', '_').replace("%", "%25").replace("\n", "%0A");
        LOGGER.info("String Encrypted Successfully");
        return res;

    }
    catch (Exception e)
    {
        LOGGER.error("encrypt Exception: "+e.getMessage());
    }


    return "";

}

and the JavaScript code, so far hammed up is below:

var encrypt = function(){
    var iterations = 31;
    var key = CryptoJS.MD5("PBEWithMD5AndDES");
    var salt = CryptoJS.enc.Hex.parse('0021002100f0005500C3009F005A0075'); 
    var options = {
        mode: CryptoJS.mode.CBC, 
        iv: salt
    };
    var hashedPassword = CryptoJS.MD5($scope.data.webPassword);
    var encryptedPassword = CryptoJS.DES.encrypt(hashedPassword, key,options).toString();
    var result = encryptedPassword.toString(CryptoJS.enc.Base64);
}

but with both the encryption the encoded string I'm getting is different.

回答1:

PBEwithMD5andDES is obsolete technology and should not be used nowadays. This answer is only provided for demonstration purposes.

PBEwithMD5andDES is defined in PKCS#5 v1.5 which is nothing more than deriving key+IV using PBKDF1 (with MD5) and encrypting with DES.

var password = CryptoJS.enc.Utf8.parse("test");
var salt = CryptoJS.enc.Hex.parse("2121F055C39F5A75");
var iterations = 31;

// PBE according to PKCS#5 v1.5 (in other words: PBKDF1)
var md5 = CryptoJS.algo.MD5.create();
md5.update(password);
md5.update(salt);
var result = md5.finalize();
md5.reset();
for(var i = 1; i < iterations; i++) {
    md5.update(result);
    result = md5.finalize();
    md5.reset();
}

// splitting key and IV
var key = CryptoJS.lib.WordArray.create(result.words.slice(0, 2));
var iv = CryptoJS.lib.WordArray.create(result.words.slice(2, 4));

var encrypted = CryptoJS.DES.encrypt("test", key, {
    iv: iv
});

enchex.innerHTML = encrypted.ciphertext.toString();
encbase64.innerHTML = encrypted.ciphertext.toString(CryptoJS.enc.Base64);

<script src="https://cdn.rawgit.com/CryptoStore/crypto-js/3.1.2/build/rollups/tripledes.js"></script>
<script src="https://cdn.rawgit.com/CryptoStore/crypto-js/3.1.2/build/rollups/md5.js"></script>
<div>Hex: <span id="enchex"></span></div>
<div>Base64: <span id="encbase64"></span></div>

Here is a jsFiddle to experiment with and here is the example Java code. Both produce the same result in Hex: aa8101a7d63093c6.

---

Security considerations:

PBEwithMD5andDES should not be used and there are better alternatives like PBEWithHmacSHA256AndAES_128 which require a slightly different approach.

The number of iterations must be large (a thousand to a million) in order to make it hard to brute-force the password. DES only provides 56 bits of security, so it is even possible to brute-force the key directly with today's means.

The salt must be randomly generated in order to achieve semantic security. The salt itself doesn't need to be secret. Since it has a known length it can be simply prepended to the ciphertext and sliced off before decryption.