Output of perl Digest::MD5 md5($data) and java MessageDigest.getInstance(“MD5”).digest($data) are different

Question

I have a perl script which uses Digest::MD5 md5($data) to obtain the 16 byte digest(which is in non readable form - binary) and this digest is used to encrypt the data. Now i have to reverse the above procedure in java ie first i need to obtain 16 byte digest using MessageDigest.getInstance("MD5").digest($data) and decrypt the message.

Now i am not sure that output digest of perl Digest::MD5 md5($data) and java digest MessageDigest.getInstance("MD5").digest($data) are same or not how do i validate this scenario.

Answer 1

1) Convert the Perl md5 from byte to hex

2) Convert the Java md5 from byte to hex ( examples here )

3) Compare the outputs

This is the Java code for the MD5 and convertion in Hex:

import java.security.MessageDigest;


public class HelloWorld
{
  public static void main(String[] args)
  {

    System.out.println("Start");

    String res=MD5("35799510369");

    System.out.print("res:"+res);

  }

 public static String MD5( String source ) {
        try {
            MessageDigest md = MessageDigest.getInstance( "MD5" );
            byte[] bytes = md.digest( source.getBytes("UTF-8") );
            return getString( bytes );
        } catch( Exception e )  {
            e.printStackTrace();
            return null;
        }
    }//end MD5()

    private static String getString( byte[] bytes ) {
        StringBuffer sb = new StringBuffer();
        for( int i=0; i<bytes.length; i++ )
        {
            byte b = bytes[ i ];
            String hex = Integer.toHexString((int) 0x00FF & b);
            if (hex.length() == 1)
            {
                sb.append("0");
            }
            sb.append( hex );
        }
        return sb.toString();
    }// end getString()

Copy and Paste the previus code in this online compiler and press COMPILE AND EXECUTE; next compare this output with the Perl md5 online script output.

---

For input=35799510369

• Perl output:

Md5 digest is .S<ë_»X³ëE&â®

The hexadecimal representation of the digest is: 012e533c9aeb5f96bb58b3eb4526e2ae

• Java output:

res:012e533c9aeb5f96bb58b3eb4526e2ae

Good luck