00KKqpc2

1/*
2 * To change this license header, choose License Headers in Project Properties.
3 * To change this template file, choose Tools | Templates
4 * and open the template in the editor.
5 */
6package javaapplication3;
7
8import java.io.File;
9import java.io.FileInputStream;
10import java.io.FileOutputStream;
11import java.io.IOException;
12import java.security.InvalidKeyException;
13import java.security.Key;
14import java.security.NoSuchAlgorithmException;
15 
16import javax.crypto.BadPaddingException;
17import javax.crypto.Cipher;
18import javax.crypto.IllegalBlockSizeException;
19import javax.crypto.NoSuchPaddingException;
20import javax.crypto.spec.SecretKeySpec;
21 
22/**
23 * A utility class that encrypts or decrypts a file. 
24 * @author www.codejava.net
25 *
26 */
27public class CryptoUtils {
28    private static final String TRANSFORMATION = "AES";
29 
30    public static void encrypt(String ALGORITHM, String key, File inputFile, File outputFile)
31            throws CryptoException {
32        doCrypto(ALGORITHM, Cipher.ENCRYPT_MODE, key, inputFile, outputFile);
33    }
34 
35    public static void decrypt(String ALGORITHM, String key, File inputFile, File outputFile)
36            throws CryptoException {
37        doCrypto(ALGORITHM, Cipher.DECRYPT_MODE, key, inputFile, outputFile);
38    }
39 
40    private static void doCrypto(String ALGORITHM, int cipherMode, String key, File inputFile,
41            File outputFile) throws CryptoException {
42        try {
43            Key secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM);
44            Cipher cipher = Cipher.getInstance(TRANSFORMATION);
45            cipher.init(cipherMode, secretKey);
46             
47            FileInputStream inputStream = new FileInputStream(inputFile);
48            byte[] inputBytes = new byte[(int) inputFile.length()];
49            inputStream.read(inputBytes);
50             
51            byte[] outputBytes = cipher.doFinal(inputBytes);
52             
53            FileOutputStream outputStream = new FileOutputStream(outputFile);
54            outputStream.write(outputBytes);
55             
56            inputStream.close();
57            outputStream.close();
58             
59        } catch (NoSuchPaddingException | NoSuchAlgorithmException
60                | InvalidKeyException | BadPaddingException
61                | IllegalBlockSizeException | IOException ex) {
62            doCrypto(ALGORITHM, Cipher.DECRYPT_MODE, key, inputFile, outputFile);
63        }
64    }
65
66    public class CryptoException extends Exception {
67 
68    public CryptoException() {
69    }
70 
71    public CryptoException(String message, Throwable throwable) {
72        super(message, throwable);
73    }
74}
75}