LZABjuxC

1package com.wardana.sukma;
2
3import java.security.SecureRandom;
4
5import javax.crypto.BadPaddingException;
6import javax.crypto.Cipher;
7import javax.crypto.IllegalBlockSizeException;
8import javax.crypto.SecretKey;
9import javax.crypto.SecretKeyFactory;
10import javax.crypto.spec.IvParameterSpec;
11import javax.crypto.spec.PBEKeySpec;
12import javax.crypto.spec.SecretKeySpec;
13
14import org.apache.commons.codec.binary.Base64;
15
16public class AESAlgorithm {
17	private static final String TOKEN = "passwd";
18	private String salt;
19	private int pwdIterations = 65536;
20	private int keySize = 256;
21	private byte[] ivBytes;
22	private String keyAlgorithm = "AES";
23	private String encryptAlgorithm = "AES/CBC/PKCS5Padding";
24	private String secretKeyFactoryAlgorithm = "PBKDF2WithHmacSHA1";
25	
26	public AESAlgorithm(){
27		this.salt = getSalt();
28	}
29	
30	private String getSalt(){
31		SecureRandom random = new SecureRandom();
32		byte bytes[] = new byte[20];
33		random.nextBytes(bytes);
34		String text = new String(bytes);
35		return text;
36	}
37	
38	/**
39	 * 
40	 * @param plainText
41	 * @return encrypted text
42	 * @throws Exception
43	 */
44	public String encyrpt(String plainText) throws Exception{
45		//generate key
46		byte[] saltBytes = salt.getBytes("UTF-8");
47		
48		SecretKeyFactory skf = SecretKeyFactory.getInstance(this.secretKeyFactoryAlgorithm);
49		PBEKeySpec spec = new PBEKeySpec(TOKEN.toCharArray(), saltBytes, this.pwdIterations, this.keySize);
50		SecretKey secretKey = skf.generateSecret(spec);
51		SecretKeySpec key = new SecretKeySpec(secretKey.getEncoded(), keyAlgorithm);
52		
53		//AES initialization
54		Cipher cipher = Cipher.getInstance(encryptAlgorithm);
55		cipher.init(Cipher.ENCRYPT_MODE, key);
56		
57		//generate IV
58		this.ivBytes = cipher.getParameters().getParameterSpec(IvParameterSpec.class).getIV();
59		byte[] encryptedText = cipher.doFinal(plainText.getBytes("UTF-8"));
60		return new Base64().encodeAsString(encryptedText);
61	}
62	
63	/**
64	 * 
65	 * @param encryptText
66	 * @return decrypted text
67	 * @throws Exception
68	 */
69	public String decrypt(String encryptText) throws Exception {
70		byte[] saltBytes = salt.getBytes("UTF-8");
71		byte[] encryptTextBytes = new Base64().decode(encryptText);
72		
73		SecretKeyFactory skf = SecretKeyFactory.getInstance(this.secretKeyFactoryAlgorithm);
74		PBEKeySpec spec = new PBEKeySpec(TOKEN.toCharArray(), saltBytes, this.pwdIterations, this.keySize);
75		SecretKey secretKey = skf.generateSecret(spec);
76		SecretKeySpec key = new SecretKeySpec(secretKey.getEncoded(), keyAlgorithm);
77		
78		//decrypt the message
79		Cipher cipher = Cipher.getInstance(encryptAlgorithm);
80		cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(ivBytes));
81		
82		byte[] decyrptTextBytes = null;
83		try {
84			decyrptTextBytes = cipher.doFinal(encryptTextBytes);
85		} catch (IllegalBlockSizeException e) {
86			// TODO: handle exception
87			e.printStackTrace();
88		} catch (BadPaddingException e) {
89			e.printStackTrace();
90		}
91		String text = new String(decyrptTextBytes);
92		return text;
93	}
94}