zM1DG7en

1package protokol_dhl;
2import java.security.KeyFactory;
3import java.security.KeyPair;
4import java.security.KeyPairGenerator;
5import java.security.NoSuchAlgorithmException;
6import java.security.PrivateKey;
7import java.security.PublicKey;
8import java.security.SecureRandom;
9import java.util.Scanner;
10import java.io.UnsupportedEncodingException;
11import java.math.BigInteger;
12import java.security.MessageDigest;
13import java.security.NoSuchAlgorithmException;
14import java.util.Arrays;
15import java.util.Base64;
16 
17import javax.crypto.Cipher;
18import javax.crypto.KeyAgreement;
19import javax.crypto.spec.DHParameterSpec;
20import javax.crypto.spec.DHPublicKeySpec;
21import javax.crypto.spec.SecretKeySpec;
22
23import javax.crypto.Cipher;
24public class Message {
25	
26	private PrivateKey privateKey;
27    private PublicKey publicKey;
28    private PublicKey receivedPublicKey;
29    private byte[] secretKey;
30    private String secretMessage;
31	
32    public Message() {};
33    public void generateKeys() 
34    {
35        try {
36            final KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("DH");
37            keyPairGenerator.initialize(1024);
38            final KeyPair keyPair = keyPairGenerator.generateKeyPair();
39            privateKey = keyPair.getPrivate();
40            publicKey  = keyPair.getPublic();
41        } catch (Exception e) {
42            e.printStackTrace();
43        }
44    }
45    public void generateCommonSecretKey() {
46
47        try {
48            final KeyAgreement keyAgreement = KeyAgreement.getInstance("DH");
49            keyAgreement.init(privateKey);
50            keyAgreement.doPhase(receivedPublicKey, true);
51
52            secretKey = shortenSecretKey(keyAgreement.generateSecret());
53        } catch (Exception e) {
54            e.printStackTrace();
55        }
56    }
57    private byte[] shortenSecretKey(final byte[] longKey) {
58
59        try {
60            final byte[] shortenedKey = new byte[8];
61            System.arraycopy(longKey, 0, shortenedKey, 0, shortenedKey.length);
62            return shortenedKey;
63        } catch (Exception e) {
64            e.printStackTrace();
65        }
66
67        return null;
68    }
69
70    public void encrypMessage( String message, Message mess) 
71    {
72        try {
73            SecretKeySpec keySpec = new SecretKeySpec(secretKey, "DES");
74            Cipher cipher  = Cipher.getInstance("DES/ECB/PKCS5Padding");
75            cipher.init(Cipher.ENCRYPT_MODE, keySpec);
76            byte[] encryptedMessage = cipher.doFinal(message.getBytes());
77            mess.DecryptMessage(encryptedMessage);
78
79        } catch (Exception e) {
80            e.printStackTrace();
81        }
82    }
83    public void DecryptMessage( byte[] message) 
84    {
85        try {
86        	SecretKeySpec keySpec = new SecretKeySpec(secretKey, "DES");
87            Cipher cipher  = Cipher.getInstance("DES/ECB/PKCS5Padding");
88            cipher.init(Cipher.DECRYPT_MODE, keySpec);
89            secretMessage = new String(cipher.doFinal(message));
90            
91        } catch (Exception e) {
92            e.printStackTrace();
93        }
94
95    }
96    public void receivePublicKeyFrom(Message mes) {
97
98        receivedPublicKey = mes.getPublicKey();
99    }
100
101    public PublicKey getPublicKey() 
102    {
103        return publicKey;
104    }
105    public void whisperTheSecretMessage() {
106
107        System.out.println(secretMessage);
108    }
109
110	// sign the messagec
111    public static String MessageText()
112    {
113		Scanner skaner=new Scanner(System.in);
114	    String message= skaner.nextLine();
115	    return message;
116    }
117    
118
119}