Prog. 4: Blockchain Cryptography Program using Java

import java.security.*; import javax.crypto.*;

/* Use of Private Key in Encryption*/

public class PrivateKeyDemo

{

static Key key; 
static Cipher cipher;

static String algorithm = “AES”;

public static void main(String args[]) throws Exception

{

key = KeyGenerator.getInstance(algorithm).generateKey(); 
cipher = Cipher.getInstance(algorithm);

String text = “FYMCA 2020 Batch Hiray College”;

byte[] encryptionBytes = encrypt(text);

System.out.println(“Original Text: “+text); 
System.out.println(“Key: “+key.toString()); 
System.out.println(“Encrypted Text: “+encrypt(text));

System.out.println(“Decrypted Text: “+decrypt(encryptionBytes));

} // End of Main Method

public static byte[] encrypt(String input) throws Exception

{

cipher.init(Cipher.ENCRYPT_MODE, key); 
byte [] inputBytes = input.getBytes(); 
return cipher.doFinal(inputBytes);

} // close of encrypt method

public static String decrypt(byte[] encryptionBytes) throws Exception

{

cipher.init(Cipher.DECRYPT_MODE, key);

byte[] convertDecrypt = cipher.doFinal(encryptionBytes); 
String convertString = new String(convertDecrypt);

return convertString;

} // close decrypt method

}

Output: