java 暗号化　復号化

Test.java

import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.*;

public class Test {
	public static void main(String ...args) throws Exception {
		String password = "01234567890ABCDEFGHIJKLMNOPQRSTU";
		encrypt("./hoge.zip", "hoge.encrypted", password);
		decrypt("hoge.encrypted", "decrpted", password);
	}

	private static void encrypt(String filename, String encryptedFilename, String password) throws Exception {
		FileInputStream fis = new FileInputStream(filename);
		Key key = new SecretKeySpec(password.getBytes(), "AES");
		Cipher cipher = Cipher.getInstance("AES/PCBC/PKCS5Padding");
		cipher.init(Cipher.ENCRYPT_MODE, key);
		FileOutputStream fos = new FileOutputStream(encryptedFilename);
		CipherOutputStream cos = new CipherOutputStream(fos, cipher);
		fos.write(cipher.getIV());
		byte[] a = new byte[8];
		int i = fis.read(a);
		while (i != -1) {
			cos.write(a, 0, i);
			i = fis.read(a);
		}
		cos.flush();
		cos.close();
	}

	private static void decrypt(String encryptedFilename, String outputFilename, String password) throws Exception {
		Key key = new SecretKeySpec(password.getBytes(), "AES");
		FileInputStream fis = new FileInputStream(encryptedFilename);
		byte[] iv = new byte[16];
		fis.read(iv);
		Cipher cipher = Cipher.getInstance("AES/PCBC/PKCS5Padding");
		IvParameterSpec ivspec = new IvParameterSpec(iv);
		cipher.init(Cipher.DECRYPT_MODE, key, ivspec);
		CipherInputStream cis = new CipherInputStream(fis, cipher);

		FileOutputStream out = new FileOutputStream(outputFilename);

		output(cis, out);
		cis.close();
		out.close();
	}
	private static void output(InputStream input , OutputStream output) throws Exception {
		int DEFAULT_BUFFER_SIZE = 1024 * 4;
		byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
		int size = -1;
		while (-1 != (size = input.read(buffer))) {
			output.write(buffer, 0, size);
		}
	}

}