Hm7E5EG3

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