package com.example.crypto.artifacts;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.GCMParameterSpec;
import java.security.*;
import java.util.Base64;
import java.util.random.*;
import java.util.Properties;
import java.util.Random;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Arrays;

public class Test {

    public static SecretKey generateAESKey()throws Exception  {
        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
        keyGen.init(256);
        return keyGen.generateKey();
    }

   
    private static byte[] getRandomWrapper1()throws Exception  {
        byte[] val = new byte[16];
        new SecureRandom().nextBytes(val);
        return val;
    }

    private static byte[] getRandomWrapper2A()throws Exception  {
        byte[] val;
        val =  getRandomWrapper1();
        funcA1(val);
        return val;
    }

    private static byte[] getRandomWrapper2b()throws Exception  {
        byte[] val;
        val =  getRandomWrapper1();
        return val;
    }

    private static void funcA1(byte[] iv)throws Exception {
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key = generateAESKey();
        cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // BAD: Reuse of `iv` in funcB1
        byte[] ciphertext = cipher.doFinal("Simple Test Data".getBytes());
    }

    private static void funcB1()throws Exception {
        byte[] iv = getRandomWrapper2A();
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key = generateAESKey();
        cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // BAD: Reuse of `iv` in funcA1
        byte[] ciphertext = cipher.doFinal("Simple Test Data".getBytes());
    }

    private static void funcA2()throws Exception {
        byte[] iv = getRandomWrapper2b();
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key = generateAESKey();
        cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // GOOD
        byte[] ciphertext = cipher.doFinal("Simple Test Data".getBytes());
    }

    private static void funcB2()throws Exception {
        byte[] iv = getRandomWrapper2b();
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key = generateAESKey();
        cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec); // GOOD
        byte[] ciphertext = cipher.doFinal("Simple Test Data".getBytes());
    }


    private static void funcA3() throws Exception {
        byte[] iv = getRandomWrapper2b();
        IvParameterSpec ivSpec1 = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key1 = generateAESKey();
        cipher.init(Cipher.ENCRYPT_MODE, key1, ivSpec1); // BAD: reuse of `iv` below
        byte[] ciphertext = cipher.doFinal("Simple Test Data".getBytes());

        IvParameterSpec ivSpec2 = new IvParameterSpec(iv);
        Cipher cipher2 = Cipher.getInstance("AES/CBC/PKCS5Padding");
        SecretKey key2 = generateAESKey();
        cipher2.init(Cipher.ENCRYPT_MODE, key2, ivSpec2); // BAD: Reuse of `iv` above
        byte[] ciphertext2 = cipher2.doFinal("Simple Test Data".getBytes());
    }




    public static void main(String[] args) {
        try{
            funcA2();
            funcB1();
            funcB2();
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
}