pbW1ChRd

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 aes;
7
8import java.io.BufferedReader;
9import java.io.IOException;
10import java.io.InputStreamReader;
11import java.security.InvalidAlgorithmParameterException;
12import java.security.InvalidKeyException;
13import java.security.NoSuchAlgorithmException;
14import java.security.SecureRandom;
15import javax.crypto.BadPaddingException;
16import javax.crypto.Cipher;
17import javax.crypto.IllegalBlockSizeException;
18import javax.crypto.KeyGenerator;
19import javax.crypto.NoSuchPaddingException;
20import javax.crypto.SecretKey;
21import javax.crypto.spec.IvParameterSpec;
22
23/**
24 *
25 * @author tpodkowski
26 */
27public class AES {
28
29    public static byte[] getTextFromUser() {
30        BufferedReader buffer = new BufferedReader(new InputStreamReader(System.in));
31        String text = "";
32
33        try {
34            text = buffer.readLine();
35        } catch (IOException e) {
36        }
37
38        return text.getBytes();
39    }
40
41    public static SecretKey getSecretKey() throws NoSuchAlgorithmException {
42        SecureRandom rand = new SecureRandom();
43        KeyGenerator keyGen = KeyGenerator.getInstance("AES");
44        keyGen.init(128, rand);
45        return keyGen.generateKey();
46    }
47
48    public static byte[] encrypt(String method, byte[] text, SecretKey secretKey) throws NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException, InvalidAlgorithmParameterException {
49        Cipher aes = Cipher.getInstance(method);
50        aes.init(Cipher.ENCRYPT_MODE, secretKey, method == "AES/CTR/NoPadding" ? new IvParameterSpec(new byte[16]) : null);
51
52        long startTime = System.nanoTime();
53
54        byte[] encryptedText = aes.doFinal(text);
55
56        double endTime = (double) (System.nanoTime() - startTime) / 1000000000.0;
57        System.out.println(method + " encryption time: " + endTime + "s");
58
59        return encryptedText;
60    }
61
62    public static byte[] decrypt(String method, byte[] encryptedText, SecretKey secretKey) throws NoSuchAlgorithmException, NoSuchPaddingException, NoSuchPaddingException, NoSuchPaddingException, NoSuchPaddingException, NoSuchPaddingException, NoSuchPaddingException, IllegalBlockSizeException, IllegalBlockSizeException, BadPaddingException, IllegalBlockSizeException, IllegalBlockSizeException, IllegalBlockSizeException, IllegalBlockSizeException, NoSuchPaddingException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException {
63        Cipher aes = Cipher.getInstance(method);
64        
65        aes.init(Cipher.DECRYPT_MODE, secretKey, method == "AES/CTR/NoPadding" ? new IvParameterSpec(new byte[16]) : null);
66
67        long startTime = System.nanoTime();
68        byte[] decryptedText = aes.doFinal(encryptedText);
69
70        double endTime = (double) (System.nanoTime() - startTime) / 1000000000.0;
71        System.out.println(method + " decryption time: " + endTime + "s");
72
73        return decryptedText;
74    }
75
76    public static void runAES(String method, byte[] text, SecretKey secretKey) throws NoSuchAlgorithmException, NoSuchPaddingException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, BadPaddingException, InvalidKeyException, InvalidKeyException, InvalidKeyException, InvalidKeyException, InvalidAlgorithmParameterException {
77        byte[] encryptedText = encrypt(method, text, secretKey);
78        byte[] decryptedText = decrypt(method, encryptedText, secretKey);
79        
80        System.out.println("Encrypted text " + method + ": " + encryptedText);
81        System.out.println("Decrypted text " + method + ": " + new String(decryptedText));
82    }
83
84    /**
85     * @param args the command line arguments
86     */
87    public static void main(String[] args) throws Exception {
88        byte[] text = getTextFromUser();
89        SecretKey secretKey = getSecretKey();
90
91        runAES("AES/ECB/PKCS5Padding", text, secretKey);
92        runAES("AES/CTR/NoPadding", text, secretKey);
93    }
94}