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comparison app/src/main/java/ch/ethz/ssh2/crypto/dh/DhExchange.java @ 438:d29cce60f393

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migrate from Eclipse to Android Studio
author Carl Byington <carl@five-ten-sg.com>
date Thu, 03 Dec 2015 11:23:55 -0800
parents src/ch/ethz/ssh2/crypto/dh/DhExchange.java@1d400fd78e4a
children
comparison
equal deleted inserted replaced
437:208b31032318 438:d29cce60f393
1 /**
2 *
3 */
4 package ch.ethz.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 private byte[] f;
62
63 @Override
64 public void init(String name) throws IOException {
65 final DHParameterSpec spec;
66
67 if ("diffie-hellman-group1-sha1".equals(name)) {
68 spec = new DHParameterSpec(P1, G);
69 }
70 else if ("diffie-hellman-group14-sha1".equals(name)) {
71 spec = new DHParameterSpec(P14, G);
72 }
73 else {
74 throw new IllegalArgumentException("Unknown DH group " + name);
75 }
76
77 try {
78 KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
79 kpg.initialize(spec);
80 KeyPair pair = kpg.generateKeyPair();
81 clientPrivate = (DHPrivateKey) pair.getPrivate();
82 clientPublic = (DHPublicKey) pair.getPublic();
83 }
84 catch (NoSuchAlgorithmException e) {
85 throw(IOException) new IOException("No DH keypair generator").initCause(e);
86 }
87 catch (InvalidAlgorithmParameterException e) {
88 throw(IOException) new IOException("Invalid DH parameters").initCause(e);
89 }
90 }
91
92 @Override
93 public byte[] getE() {
94 if (clientPublic == null)
95 throw new IllegalStateException("DhExchange not initialized!");
96
97 return clientPublic.getY().toByteArray();
98 }
99
100 @Override
101 protected byte[] getServerE() {
102 if (serverPublic == null)
103 throw new IllegalStateException("DhExchange not initialized!");
104
105 return serverPublic.getY().toByteArray();
106 }
107
108 @Override
109 public byte[] getF() {
110 return f;
111 }
112
113 @Override
114 public void setF(byte[] f) throws IOException {
115 if (clientPublic == null)
116 throw new IllegalStateException("DhExchange not initialized!");
117
118 final KeyAgreement ka;
119
120 try {
121 KeyFactory kf = KeyFactory.getInstance("DH");
122 DHParameterSpec params = clientPublic.getParams();
123 this.f = f;
124 this.serverPublic = (DHPublicKey) kf.generatePublic(new DHPublicKeySpec(
125 new BigInteger(f), params.getP(), params.getG()));
126 ka = KeyAgreement.getInstance("DH");
127 ka.init(clientPrivate);
128 ka.doPhase(serverPublic, true);
129 }
130 catch (NoSuchAlgorithmException e) {
131 throw(IOException) new IOException("No DH key agreement method").initCause(e);
132 }
133 catch (InvalidKeyException e) {
134 throw(IOException) new IOException("Invalid DH key").initCause(e);
135 }
136 catch (InvalidKeySpecException e) {
137 throw(IOException) new IOException("Invalid DH key").initCause(e);
138 }
139
140 sharedSecret = new BigInteger(ka.generateSecret());
141 }
142
143 @Override
144 public String getHashAlgo() {
145 return "SHA1";
146 }
147 }