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 world
Output : d9cce882ee690a5c1ce70beff3a78c77Input : GeeksForGeeks
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 GFG { 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 = "GeeksForGeeks" ; System.out.println( "
" + s1 + " : " + encryptThisString(s1)); String s2 = "hello world" ; System.out.println( "
" + s2 + " : " + encryptThisString(s2)); } } |
Output:
HashCode Generated by MD2 for: GeeksForGeeks : 787df774a3d25dca997b1f1c8bfee4af hello world : d9cce882ee690a5c1ce70beff3a78c77
Application:
- Cryptography
- Data Integrity
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