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comparison src/com/trilead/ssh2/crypto/dh/DhExchange.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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-1:000000000000 0:0ce5cc452d02
1 /**
2 *
3 */
4 package com.trilead.ssh2.crypto.dh;
5
6 import java.io.IOException;
7 import java.math.BigInteger;
8 import java.security.InvalidAlgorithmParameterException;
9 import java.security.InvalidKeyException;
10 import java.security.KeyFactory;
11 import java.security.KeyPair;
12 import java.security.KeyPairGenerator;
13 import java.security.NoSuchAlgorithmException;
14 import java.security.spec.InvalidKeySpecException;
15
16 import javax.crypto.KeyAgreement;
17 import javax.crypto.interfaces.DHPrivateKey;
18 import javax.crypto.interfaces.DHPublicKey;
19 import javax.crypto.spec.DHParameterSpec;
20 import javax.crypto.spec.DHPublicKeySpec;
21
22 /**
23 * @author kenny
24 *
25 */
26 public class DhExchange extends GenericDhExchange {
27
28 /* Given by the standard */
29
30 private static final BigInteger P1 = new BigInteger(
31 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
32 + "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
33 + "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
34 + "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
35 + "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381"
36 + "FFFFFFFFFFFFFFFF", 16);
37
38 private static final BigInteger P14 = new BigInteger(
39 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
40 + "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
41 + "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
42 + "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
43 + "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
44 + "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
45 + "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
46 + "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
47 + "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
48 + "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
49 + "15728E5A8AACAA68FFFFFFFFFFFFFFFF", 16);
50
51 private static final BigInteger G = BigInteger.valueOf(2);
52
53 /* Client public and private */
54
55 private DHPrivateKey clientPrivate;
56 private DHPublicKey clientPublic;
57
58 /* Server public */
59
60 private DHPublicKey serverPublic;
61
62 @Override
63 public void init(String name) throws IOException {
64 final DHParameterSpec spec;
65
66 if ("diffie-hellman-group1-sha1".equals(name)) {
67 spec = new DHParameterSpec(P1, G);
68 }
69 else if ("diffie-hellman-group14-sha1".equals(name)) {
70 spec = new DHParameterSpec(P14, G);
71 }
72 else {
73 throw new IllegalArgumentException("Unknown DH group " + name);
74 }
75
76 try {
77 KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
78 kpg.initialize(spec);
79 KeyPair pair = kpg.generateKeyPair();
80 clientPrivate = (DHPrivateKey) pair.getPrivate();
81 clientPublic = (DHPublicKey) pair.getPublic();
82 }
83 catch (NoSuchAlgorithmException e) {
84 throw(IOException) new IOException("No DH keypair generator").initCause(e);
85 }
86 catch (InvalidAlgorithmParameterException e) {
87 throw(IOException) new IOException("Invalid DH parameters").initCause(e);
88 }
89 }
90
91 @Override
92 public byte[] getE() {
93 if (clientPublic == null)
94 throw new IllegalStateException("DhExchange not initialized!");
95
96 return clientPublic.getY().toByteArray();
97 }
98
99 @Override
100 protected byte[] getServerE() {
101 if (serverPublic == null)
102 throw new IllegalStateException("DhExchange not initialized!");
103
104 return serverPublic.getY().toByteArray();
105 }
106
107 @Override
108 public void setF(byte[] f) throws IOException {
109 if (clientPublic == null)
110 throw new IllegalStateException("DhExchange not initialized!");
111
112 final KeyAgreement ka;
113
114 try {
115 KeyFactory kf = KeyFactory.getInstance("DH");
116 DHParameterSpec params = clientPublic.getParams();
117 this.serverPublic = (DHPublicKey) kf.generatePublic(new DHPublicKeySpec(
118 new BigInteger(f), params.getP(), params.getG()));
119 ka = KeyAgreement.getInstance("DH");
120 ka.init(clientPrivate);
121 ka.doPhase(serverPublic, true);
122 }
123 catch (NoSuchAlgorithmException e) {
124 throw(IOException) new IOException("No DH key agreement method").initCause(e);
125 }
126 catch (InvalidKeyException e) {
127 throw(IOException) new IOException("Invalid DH key").initCause(e);
128 }
129 catch (InvalidKeySpecException e) {
130 throw(IOException) new IOException("Invalid DH key").initCause(e);
131 }
132
133 sharedSecret = new BigInteger(ka.generateSecret());
134 }
135
136 @Override
137 public String getHashAlgo() {
138 return "SHA1";
139 }
140 }