Calculate the message digest of a text using the SHA-1 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  A hash function is a special mathematical function that converts a numerical input value of arbitrary length into another compressed numerical value(fixed length). A hash performs one-way encryption.Values returned by a hash function are called message digest or simply hash values. hash codes or simply hashes.

Ø  It is fundamental part of password security, in terms of database storage. A hash function responsible for changing a text password into a more complex set of characters by using more complex operations than a familiar mathematical operation such as multiplication.

Ø  Using hashes and hexadecimal formats can help those who are storing passwords on a database to confuse hackers.

Ø  The Secure Hash Algorithm 1 (SHA-1) is a cryptographic computer security algorithm.SHA-1 produces a 160-bit hash value from the inputted data (data that requires encryption).

Ø  SHA-1 is commonly used in cryptographic applications and environments where the requirements  for data integrity is high.  Some of the protocols that use SHA-1 include:

·     Transport Layer Security (TLS)

·     Secure Sockets Layer (SSL

·     Pretty Good Privacy (PGP)

·     Secure Shell (SSH)

·     Secure/Multipurpose Internet Mail Extensions (S/MIME)

·     Internet Protocol Security (IPSec)

SOURCE CODE:

import java.security.*;

public class SHA1 {

    public static void main(String[] a) {

        try {

            MessageDigest md = MessageDigest.getInstance("SHA1");

            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("SHA1(\"" + input + "\")=" + bytesToHex(output));

            input = "abc";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("SHA1(\"" + input + "\")=" + bytesToHex(output));

            input = "abcdefghijklmnopqrstuvwxyz";

            md.update(input.getBytes());

            output = md.digest();

            System.out.println();

            System.out.println("SHA1(\"" + 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]);

        }

        /*

        for loop in optimized way

        for (byte aB : b) {

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

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

        }

        */

        return buf.toString();

    }

}

OUTPUT:

VIVA QUESTIONS:

1.  What is JAVA?

2. What is SHA-1 Algorithm?

3. What is java script?

4. What is Cryptography?

5. What is Encryption?

                  6. What is Decryption?