package zomatosearch.example.com.zomatosearch;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.security.SecureRandom;

import java.util.Base64;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.IvParameterSpec;

import javax.crypto.spec.SecretKeySpec;

public class AES_Encryption {

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

//Generating Key For Encryption

KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");

keyGenerator.init(128);

// Generate Key

SecretKey key = keyGenerator.generateKey();

byte[] IV = new byte[16];

SecureRandom random = new SecureRandom();

random.nextBytes(IV);

//File to be red

File inputFile = new File(System.getProperty("user.dir") + "/rohit.txt");

//File to be written using cipher text

File outputFileEnc = new File(System.getProperty("user.dir") + "/rohit_enc.txt");

//Decrypted File

File outputFileDec = new File(System.getProperty("user.dir") + "/rohit_dec.txt");

//Stream to read normal file

FileInputStream inputStream = new FileInputStream(inputFile);

//creating byte array of same length as of file

byte[] inputBytes = new byte[(int) inputFile.length()];

//Putting into byteArray

inputStream.read(inputBytes);

//getting the cipher text

byte[] cipherText = encrypt(inputBytes, key, IV);

//Writing encrypted text into file

FileOutputStream outputStream = new FileOutputStream(outputFileEnc);

outputStream.write(cipherText);

outputStream = new FileOutputStream(outputFileDec);

byte[] decrypted = new byte[(int) outputFileEnc.length()];

FileInputStream fileInputStream = new FileInputStream(outputFileEnc);

fileInputStream.read(decrypted);

outputStream.write(decrypt(decrypted, key, IV));

inputStream.close();

outputStream.close();

}

public static byte[] encrypt(byte[] plaintext, SecretKey key, byte[] IV) throws Exception {

//Get Cipher Instance

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

//Create SecretKeySpec

SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "AES");

//Create IvParameterSpec

IvParameterSpec ivSpec = new IvParameterSpec(IV);

//Initialize Cipher for ENCRYPT_MODE

cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);

//Perform Encryption

byte[] cipherText = cipher.doFinal(plaintext);

return cipherText;

}

public static byte[] decrypt(byte[] cipherText, SecretKey key, byte[] IV) throws Exception {

//Get Cipher Instance

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

//Create SecretKeySpec

SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "AES");

//Create IvParameterSpec

IvParameterSpec ivSpec = new IvParameterSpec(IV);

//Initialize Cipher for DECRYPT_MODE

cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);

//Perform Decryption

byte[] decryptedText = cipher.doFinal(cipherText);

return decryptedText;

}

}