Calculate the message digest of a text using the MD5 algorithm in JAVA | Cryptography

HARDWARE AND SOFTWARE REQUIREMENT:

1. Intel based Desktop PC: - RAM of 512 MB

2. Notepad/Notepad ++ editor

3. Net beans / Eclipse

THEORY:

Ø  The MD5 hashing algorithm is a one-way cryptographic function that accepts a message of any length as input and returns as output a fixed-length digest value to be used for authenticating the original message.

Ø  The MD5 hash function was originally designed for use as a secure cryptographic hash algorithm for authenticating digital signatures(to validate the authenticity and integrity of a message, software or digital document)

Ø  MD5 is used for storing securing password in database server. MD5 generated message digest of 128 bits.

SOURCE CODE:

import java.security.*;

public class MD5 {

    public static void main(String[] a) {

        try {

            MessageDigest md = MessageDigest.getInstance("MD5");

            System.out.println("Message digest object info:");

            System.out.println("          Algorithm=" + md.getAlgorithm());

            System.out.println("          Provider=" + md.getProvider());

            System.out.println("          ToString=" + md.toString());

            String input = "";

            md.update(input.getBytes());

            byte[] output = md.digest();

            System.out.println();

            System.out.println("MD5(\"" + input + "\")=" + bytesToHex(output));

            input = "abc";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("MD5(\"" + input + "\")=" + bytesToHex(output));

            input = "abd";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("MD5(\"" + input + "\")=" + bytesToHex(output));

            input = "abcdefghijklmnopqrstuvwxyz";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("MD5(\"" + input + "\")=" + bytesToHex(output));

            input = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("MD5(\"" + input + "\")=" + bytesToHex(output));

            System.out.println();

        } catch (Exception e) {

            System.out.println("Exception:" + e);

        }

    }

    private static String bytesToHex(byte[] b) {

        char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

        StringBuffer buf = new StringBuffer();

        for (int j = 0; j < b.length; j++) {

            buf.append(hexDigit[(b[j] >> 4) & 0x0f]);

            buf.append(hexDigit[b[j] & 0x0f]);

        }

        return buf.toString();

    }

}

OUTPUT:

VIVA QUESTIONS:

1.What is JAVA?

2.What is MD5 Algorithm?

3.What is java script?

4.What is Cryptography?

5.What is Encryption?

6.What is Decryption?