PBKDF2, Java Implementation from C#

Question

Trying to get a java implementation of PBKDF2, I used this as my C# version: https://github.com/shawnmclean/SimpleCrypto.net

My code:

import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;

import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

public class PBKDF2 {

    public static void main(String[] args) {
        try {
            SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
            KeySpec ks = new PBEKeySpec("iamtwentycharacterss".toCharArray(),"50.eGIYr3ZpxpWw67utH17s/A==".getBytes(),50,64);
            SecretKey s = f.generateSecret(ks);
            Key k = new SecretKeySpec(s.getEncoded(),"HmacSHA1");
            System.out.println(new String(k.getEncoded()));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        }       
    }

}

I've tried various answers on stackoverflow:

Java SimpleCrypto Class for encryption / decryption producing different results in Coldfusion 9 and Java (Android)

Java - PBKDF2 with HMACSHA256 as the PRF

Password Verification with PBKDF2 in Java

Unfortunately the result's don't match, the result is supposed to be: mOs/Mw7ZRM99i/BTJ+xnmj5Pm6QlqP1vuPqrf/Qa3WwassxI1QJ447OqdoBzunbJjvrx7+bHAO1Dnj8ltS4TKA==

your result is base64 encoded but in your program i didn't see any base 64 encoding code — Dungeon Hunter, Jul 24 '12 at 12:42
Okay I have added a base 64 encoding using the apache commons library but I still get an invalid result. — Michael, Jul 24 '12 at 14:26

score 2 · Accepted Answer · answered Jul 24 '12 at 14:48

I have resolved my issue with the following code if it may be of assistance, Rfc2898DeriveBytes class: http://pastebin.com/iReZJ3Vq

import java.nio.charset.Charset;

import org.bouncycastle.util.encoders.Base64;

public class PBKDF2 {

    public static void main(String[] args) {
        try {
            String password = "iamtwentycharacterss";
            String salt = "50.eGIYr3ZpxpWw67utH17s/A==";
            int iterations = Integer.parseInt(salt.substring(0, salt.indexOf('.')));
            byte[] saltBytes = salt.getBytes(Charset.forName("UTF-8"));

            Rfc2898DeriveBytes rfc2898 = new Rfc2898DeriveBytes(password, saltBytes, iterations);
            byte[] key = rfc2898.getBytes(64);
            String hash = new String(Base64.encode(key));
            System.out.println(hash);
        } catch (Exception ex) {
            System.out.println("ERROR: " + ex);
        }
    }

}

score 0 · Answer 2 · answered Jul 24 '12 at 15:01

How i missed this point....

The desired key length in the program is 64 but the result's key length you are expecting is 512. Change desired key length in the pbekeyspec to 512

KeySpec ks = new PBEKeySpec("iamtwentycharacterss".toCharArray(),"50.eGIYr3ZpxpWw67utH17s/A==".getBytes(),50,512);

PBKDF2, Java Implementation from C#

2 Answers2