How to encrypt password using md5 with key in android

I am currently using the following code to encrypt password but it is without using key.

package com.MD5Check;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import androi开发者_如何学运维d.app.Activity;
import android.os.Bundle;

public class MD5Check extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        getSignature();
    }

    public void getSignature()
    {
        try {
               String s = "aditi9970";
               MessageDigest md5 = MessageDigest.getInstance("MD5");
               md5.update(s.getBytes(),0,s.length());
               String signature = new BigInteger(1,md5.digest()).toString(16);
               System.out.println("Signature: "+signature);

            } catch (final NoSuchAlgorithmException e) {
               e.printStackTrace();
            }
    }
} 

I would like to hash the password using md5 with key in android.

Can anybody suggest the right way to do this?

MD5 is a hashing algorithm - meaning that the function will only transform data one way (from the original into an md5 hash). I am a little unclear what you mean by 'key' in these circumstances. If you are looking to salt the string before hashing it then you can simply concatenate your original string and your salt.

Alternatively you may wish to look at alternative android encryption techniques. I would start here http://developer.android.com/reference/javax/crypto/package-summary.html