converting java to perl (md5) - md5

Question

I am trying converting java to perl (md5)program.
How can i do following two programs same output MD5 sum.
Java
import java.security.MessageDigest;
import java.math.BigInteger;
public class Hash
{
public static void main( String[] args ) throws Exception
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
String plain = "abcd1234";
BigInteger digest = new BigInteger(md5.digest(plain.getBytes("UTF-8")));
System.out.println( digest.abs() );
}
}
Perl
use Digest::MD5 'md5_hex';
use Math::BigInt;
my $plain = "abcd1234";
my $digest = Math::BigInt::->from_hex(md5_hex $plain);
print $digest, "\n";
I Think,
Java:
BigInteger digest = new BigInteger(md5.digest(plain.getBytes("UTF-8")));
Perl:
my $digest = Math::BigInt::->from_hex(md5_hex $plain);
here is diffrent output MD5 sum.
I want to edit perl source.

Answer 1

Your BigInteger() call requires a byte array containing the two's complement binary representation of the number. You need to use the sign-magnitude constructor:
public BigInteger(int signum, byte[] magnitude)
So, your Java code should be:
import java.security.MessageDigest;
import java.math.BigInteger;
public class Hash
{
public static void main(String[] args) throws Exception
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
String plain = "abcd1234";
BigInteger digest = new BigInteger(1, md5.digest(plain.getBytes("UTF-8")));
System.out.println(digest.abs());
}
}
Your Perl code didn't quite work for me, either. My version of Math::BigInt requires a string representation of the hex value, like so:
use Digest::MD5 'md5_hex';
use Math::BigInt;
my $plain = "abcd1234";
my $digest = Math::BigInt::->from_hex('0x' . md5_hex($plain));
print $digest, "\n";
When I run those two commands, I get the same digest value displayed.