HashCollider.java Source code

Introduction

Here is the source code for HashCollider.java

Source

/*
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import java.math.BigInteger;
import java.util.Random;
import org.apache.commons.codec.digest.DigestUtils;

/**
 *
 * @author abbas
 */
public class HashCollider {

    /**i
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Random random = new Random();
        byte[] nbytes1 = new byte[64];
        byte[] nbytes2 = new byte[64];
        float average = 0;
        // set number of bits for checking collision
        int number_of_bits = 4;
        random.nextBytes(nbytes1);
        random.nextBytes(nbytes2);

        String sha1 = DigestUtils.sha256Hex(nbytes1);
        String sha2 = DigestUtils.sha256Hex(nbytes2);

        String nsh1 = new BigInteger(sha1, 16).toString(2);
        String nsh2 = new BigInteger(sha2, 16).toString(2);
        int i = 0;
        for (int j = 0; j < 5; j++) {
            while (true) {
                if (nsh1.substring(0, number_of_bits - 1).equals(nsh2.substring(0, number_of_bits - 1))) {
                    System.out.println(i);
                    average += i;
                    break;
                }
                i++;
                //            System.out.println("......"+i);
                random.nextBytes(nbytes1);
                random.nextBytes(nbytes2);
                sha1 = DigestUtils.sha256Hex(nbytes1);
                sha2 = DigestUtils.sha256Hex(nbytes2);
                nsh1 = new BigInteger(sha1, 16).toString(2);
                nsh2 = new BigInteger(sha2, 16).toString(2);
            }
            i = 0;
            //        System.out.println(nsh1+"\n"+nsh2);
            random.nextBytes(nbytes1);
            random.nextBytes(nbytes2);
            sha1 = DigestUtils.sha256Hex(nbytes1);
            sha2 = DigestUtils.sha256Hex(nbytes2);
            nsh1 = new BigInteger(sha1, 16).toString(2);
            nsh2 = new BigInteger(sha2, 16).toString(2);

        }
        //
        System.out.println("Average for  " + number_of_bits + " bits is  " + average / 5);

    }

}