Equivalent of PHP's crypt function in Java

Question

I am migrating my PHP code to Google App Engine - Java.
So I need an equivalent of PHP's crypt function in Java,
since I have stored all the passwords of registered users
using crypt in my DB.

Edit 1: Here is my php code for encrypting passwords :

$password = "test123";
$pwd = crypt($password,$password);
echo $pwd;

Output is (On Windows as well as a linux based server on HostMonser):
temjCCsjBECmU

Can someone give me equivalted java code?
I have tried various permutations & combinations with
MessageDigest class, but can't get it right..

Edit 2:
Here is sample code which I thought would work but did not:

try {
                {
                    String password = "test123";
                    MessageDigest digest = MessageDigest.getInstance( "MD5" ); 
                    byte[] passwordBytes = password.getBytes( ); 

                    digest.reset( );
                    digest.update( passwordBytes );
                    digest.update( passwordBytes );
                    byte[] message = digest.digest( );

                    StringBuffer hexString = new StringBuffer();
                    for ( int i=0; i < message.length; i++) 
                    {
                        hexString.append( Integer.toHexString(
                            0xFF & message[ i ] ) );
                    }
                    String encrypted = hexString.toString();
                    System.out.println(encrypted);
                  } } catch (NoSuchAlgorithmException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }

Answer 1

Well, PHP's crypt isn't actually encryption as far as I know. It's just a wrapper around some one-way hashing functions I believe, so if your current PHP site's using crypt's MD5 or SHA256 or whatever, I'd expect that you could find those equivalent hashing classes/functions in Java.

Answer 2

You have to know what implementation of PHP crypt has been used (MD5? SHA256? SHA512?) because there are several, depending on your OS : http://php.net/manual/fr/function.crypt.php

The Java equivalent class is MessageDigest. When you create an instance of this class, you provide the hash algorithm, for example :

MessageDigest md = MessageDigest.getInstance("MD5");
MessageDigest md2 = MessageDigest.getInstance("SHA-256");
MessageDigest md3 = MessageDigest.getInstance("SHA-512");
// etc.
byte[] encryptedPassword = md.digest("yourPassword".getBytes());

Answer 3

You need to take a look at the java.security classes (what used to tbe the JCE):

In there you'll find everything you need to do what you want (depending on which algorithm you need).

http://download.oracle.com/docs/cd/E17409_01/javase/6/docs/api/java/security/package-summary.html

e.g. MessageDigest for MD5/SHA etc:

http://download.oracle.com/docs/cd/E17409_01/javase/6/docs/api/java/security/MessageDigest.html

Check these against the Google App Engine whitelist here, I'm not sure what's supported and what isn't.

http://code.google.com/appengine/docs/java/jrewhitelist.html

The java.security stuff can be a bit of a pain to work with sometimes, you may alternatively want to use Jasypt - which is a more simplified API that works with any JCE:

http://www.jasypt.org/

Answer 4

It seems you have to work with a legacy database already populated with passwords you cannot discard, so you can't just switch to a salted MessageDigest, preferably using SHA-1. And your problem gets more complicated, since PHP's crypt is a wrapper that might use one of several algorithms. But let's assume your PHP uses the original DES-based UNIX crypt, then all you need is an implementation of that in Java. As far as i know, there is no implementation of UNIX's crypt in the standard Java installation, but you might want to look here for a list of options.

Answer 5

PHP's crypt supports multiple hash functions. If you use the MD5 version (hash starts with $1$), you can find a Java implementation here,

http://www.java2s.com/Open-Source/Java-Document/Groupware/LibreSource/md5/MD5Crypt.java.htm

Please notice that they use their own MD5 class. I am not sure if it's the same as standard MD5.

I am sure you can find Java implementation for other hash algorithms too.