MD2 Hash In Java

The MD2 is a Message-Digest Algorithm. It is a cryptographic hash function developed by Ronald Rivest in 1989. It is optimized for 8-bit computers. The MD2 algorithm is used in public key infrastructures as part of certificates generated with MD2 and RSA. From 2014, this algorithm is now not considered as a secure algorithm.

To calculate cryptographic hashing value in Java, MessageDigest Class is used, under the package java.security.

MessagDigest Class provides following cryptographic hash function to find hash value of a text as follows:

MD2
MD5
SHA-1
SHA-224
SHA-256
SHA-384
SHA-512
These algorithms are initialized in static method called getInstance(). After selecting the algorithm the message digest value is calculated and the results are returned as a byte array. BigInteger class is used, to convert the resultant byte array into its signum representation. This representation is then converted into a hexadecimal format to get the expected MessageDigest.

Examples:

Input : Hello Everyone
Output : d9cce882ee690a5c1ce70beff3a78c77

Input : Prutor.ai
Output : 787df774a3d25dca997b1f1c8bfee4af

Below program shows the implementation of MD2 hash in Java.

// Java program to calculate MD2 hash value

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

public class Prutor {
public static String encryptThisString(String input)
{
try {
// getInstance() method is called with algorithm MD2
MessageDigest md = MessageDigest.getInstance("MD2");

// digest() method is called
// to calculate message digest of the input string
// returned as array of byte
byte[] messageDigest = md.digest(input.getBytes());

// Convert byte array into signum representation
BigInteger no = new BigInteger(1, messageDigest);

// Convert message digest into hex value
String hashtext = no.toString(16);

// Add preceding 0s to make it 32 bit
while (hashtext.length() < 32) {
hashtext = "0" + hashtext;
}

// return the HashText
return hashtext;
}

// For specifying wrong message digest algorithms
catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}

// Driver code
public static void main(String args[]) throws
NoSuchAlgorithmException
{
System.out.println("HashCode Generated by MD2 for: ");

String s1 = "Prutor.ai";
System.out.println("n" + s1 + " : " + encryptThisString(s1));

String s2 = "Hello Everyone";
System.out.println("n" + s2 + " : " + encryptThisString(s2));
}
}
Result :

HashCode Generated by MD2 for:

Prutor.ai : 787df774a3d25dca997b1f1c8bfee4af

Hello Everyone : d9cce882ee690a5c1ce70beff3a78c77
Application:

Cryptography
Data Integrity