Java Crypto hello world #lab

Main.java

package io.github.benas.labs.javase.crypto;

import javax.crypto.*;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import java.io.IOException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) throws IOException,
            NoSuchAlgorithmException, InvalidKeySpecException,
            NoSuchPaddingException, InvalidKeyException,
            InvalidAlgorithmParameterException, IllegalBlockSizeException,
            BadPaddingException {
        // In order to use Password-Based Encryption (PBE) as defined in PKCS
        // #5, we have to specify a salt and an iteration count. The same salt
        // and iteration count that are used for encryption must be used for
        // decryption:

        PBEKeySpec pbeKeySpec;
        PBEParameterSpec pbeParamSpec;
        SecretKeyFactory keyFac;

        // Salt
        byte[] salt = {(byte) 0xc7, (byte) 0x73, (byte) 0x21, (byte) 0x8c,
                (byte) 0x7e, (byte) 0xc8, (byte) 0xee, (byte) 0x99};

        // Iteration count
        int count = 20;

        // Create PBE parameter set
        pbeParamSpec = new PBEParameterSpec(salt, count);

        // Prompt user for encryption password.
        // Collect user password as char array (using the
        // "readPasswd" method from above), and
        System.out.print("Enter the encrypted message: ");

        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();

        byte[] input = s.getBytes();

        System.out.println("string length =" + s.length());
        System.out.println("byte length =" + input.length);
        System.out.print("Enter the encryption password: ");
        System.out.println("password = mbh");

        pbeKeySpec = new PBEKeySpec("mbh".toCharArray());

        // convert it into a SecretKey object, using a PBE key
        // factory
        keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");

        SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);

        // Create PBE Cipher
        Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");

        pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);

        byte[] clearTextdecrypted;
        try {
            clearTextdecrypted = pbeCipher.doFinal(input);
            System.out.println("decrypted message is : " + new String(clearTextdecrypted));
        } catch (BadPaddingException e) {
            System.err.println("wrong password!" + e.getMessage());
        }

    }

}