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1package com.bbva.arq.front.spring.optg01.optg01.batch;
2
3import java.io.FileInputStream;
4import java.io.FileOutputStream;
5import java.io.IOException;
6import java.io.InputStream;
7import java.io.OutputStream;
8
9import javax.crypto.Cipher;
10import javax.crypto.CipherInputStream;
11import javax.crypto.CipherOutputStream;
12import javax.crypto.SecretKey;
13import javax.crypto.SecretKeyFactory;
14import javax.crypto.spec.DESKeySpec;
15
16public class Decrypter {
17
18	public static void main(String[] args) {
19		try {
20			String key = "squirrel123"; // needs to be at least 8 characters for DES
21
22			FileInputStream fis = new FileInputStream("original.txt");
23			FileOutputStream fos = new FileOutputStream("encrypted.txt");
24			encrypt(key, fis, fos);
25
26			FileInputStream fis2 = new FileInputStream("encrypted.txt");
27			FileOutputStream fos2 = new FileOutputStream("decrypted.txt");
28			decrypt(key, fis2, fos2);
29		} catch (Throwable e) {
30			e.printStackTrace();
31		}
32	}
33
34	public static void encrypt(String key, InputStream is, OutputStream os) throws Exception {
35		encryptOrDecrypt(key, Cipher.ENCRYPT_MODE, is, os);
36	}
37
38	public static void decrypt(String key, InputStream is, OutputStream os) throws Exception {
39		encryptOrDecrypt(key, Cipher.DECRYPT_MODE, is, os);
40	}
41
42	public static void encryptOrDecrypt(String key, int mode, InputStream is, OutputStream os) throws Exception {
43
44		DESKeySpec dks = new DESKeySpec(key.getBytes());
45		SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
46		SecretKey desKey = skf.generateSecret(dks);
47		Cipher cipher = Cipher.getInstance("DES"); // DES/ECB/PKCS5Padding for SunJCE
48
49		if (mode == Cipher.ENCRYPT_MODE) {
50			cipher.init(Cipher.ENCRYPT_MODE, desKey);
51			CipherInputStream cis = new CipherInputStream(is, cipher);
52			doCopy(cis, os);
53		} else if (mode == Cipher.DECRYPT_MODE) {
54			cipher.init(Cipher.DECRYPT_MODE, desKey);
55			CipherOutputStream cos = new CipherOutputStream(os, cipher);
56			doCopy(is, cos);
57		}
58	}
59
60	public static void doCopy(InputStream is, OutputStream os) throws IOException {
61		byte[] bytes = new byte[64];
62		int numBytes;
63		while ((numBytes = is.read(bytes)) != -1) {
64			os.write(bytes, 0, numBytes);
65		}
66		os.flush();
67		os.close();
68		is.close();
69	}
70}