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Java > Open Source Codes > com > jcraft > jsch > jce > SignatureDSA


1 /* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
2 /*
3 Copyright (c) 2002,2003,2004,2005,2006 ymnk, JCraft,Inc. All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without
6 modification, are permitted provided that the following conditions are met:
7
8   1. Redistributions of source code must retain the above copyright notice,
9      this list of conditions and the following disclaimer.
10
11   2. Redistributions in binary form must reproduce the above copyright
12      notice, this list of conditions and the following disclaimer in
13      the documentation and/or other materials provided with the distribution.
14
15   3. The names of the authors may not be used to endorse or promote products
16      derived from this software without specific prior written permission.
17
18 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
19 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
21 INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
22 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
24 OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
25 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
26 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
27 EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 package com.jcraft.jsch.jce;
31
32 import java.math.BigInteger JavaDoc;
33 import java.security.*;
34 import java.security.spec.*;
35
36 public class SignatureDSA implements com.jcraft.jsch.SignatureDSA{
37
38   java.security.Signature JavaDoc signature;
39   KeyFactory keyFactory;
40
41   public void init() throws Exception JavaDoc{
42     signature=java.security.Signature.getInstance("SHA1withDSA");
43     keyFactory=KeyFactory.getInstance("DSA");
44   }
45   public void setPubKey(byte[] y, byte[] p, byte[] q, byte[] g) throws Exception JavaDoc{
46     DSAPublicKeySpec dsaPubKeySpec =
47     new DSAPublicKeySpec(new BigInteger JavaDoc(y),
48                  new BigInteger JavaDoc(p),
49                  new BigInteger JavaDoc(q),
50                  new BigInteger JavaDoc(g));
51     PublicKey pubKey=keyFactory.generatePublic(dsaPubKeySpec);
52     signature.initVerify(pubKey);
53   }
54   public void setPrvKey(byte[] x, byte[] p, byte[] q, byte[] g) throws Exception JavaDoc{
55     DSAPrivateKeySpec dsaPrivKeySpec =
56     new DSAPrivateKeySpec(new BigInteger JavaDoc(x),
57                   new BigInteger JavaDoc(p),
58                   new BigInteger JavaDoc(q),
59                   new BigInteger JavaDoc(g));
60     PrivateKey prvKey = keyFactory.generatePrivate(dsaPrivKeySpec);
61     signature.initSign(prvKey);
62   }
63   public byte[] sign() throws Exception JavaDoc{
64     byte[] sig=signature.sign();
65 /*
66 System.err.print("sign["+sig.length+"] ");
67 for(int i=0; i<sig.length;i++){
68 System.err.print(Integer.toHexString(sig[i]&0xff)+":");
69 }
70 System.err.println("");
71 */
72     // sig is in ASN.1
73 // SEQUENCE::={ r INTEGER, s INTEGER }
74 int len=0;
75     int index=3;
76     len=sig[index++]&0xff;
77 //System.err.println("! len="+len);
78 byte[] r=new byte[len];
79     System.arraycopy(sig, index, r, 0, r.length);
80     index=index+len+1;
81     len=sig[index++]&0xff;
82 //System.err.println("!! len="+len);
83 byte[] s=new byte[len];
84     System.arraycopy(sig, index, s, 0, s.length);
85
86     byte[] result=new byte[40];
87
88     // result must be 40 bytes, but length of r and s may not be 20 bytes
89
90     System.arraycopy(r, (r.length>20)?1:0,
91              result, (r.length>20)?0:20-r.length,
92              (r.length>20)?20:r.length);
93     System.arraycopy(s, (s.length>20)?1:0,
94              result, (s.length>20)?20:40-s.length,
95              (s.length>20)?20:s.length);
96  
97 // System.arraycopy(sig, (sig[3]==20?4:5), result, 0, 20);
98 // System.arraycopy(sig, sig.length-20, result, 20, 20);
99
100     return result;
101   }
102   public void update(byte[] foo) throws Exception JavaDoc{
103    signature.update(foo);
104   }
105   public boolean verify(byte[] sig) throws Exception JavaDoc{
106     int i=0;
107     int j=0;
108     byte[] tmp;
109
110     if(sig[0]==0 && sig[1]==0 && sig[2]==0){
111     j=((sig[i++]<<24)&0xff000000)|((sig[i++]<<16)&0x00ff0000)|
112     ((sig[i++]<<8)&0x0000ff00)|((sig[i++])&0x000000ff);
113     i+=j;
114     j=((sig[i++]<<24)&0xff000000)|((sig[i++]<<16)&0x00ff0000)|
115     ((sig[i++]<<8)&0x0000ff00)|((sig[i++])&0x000000ff);
116     tmp=new byte[j];
117     System.arraycopy(sig, i, tmp, 0, j); sig=tmp;
118     }
119
120     // ASN.1
121 int frst=((sig[0]&0x80)!=0?1:0);
122     int scnd=((sig[20]&0x80)!=0?1:0);
123     //System.err.println("frst: "+frst+", scnd: "+scnd);
124
125     int length=sig.length+6+frst+scnd;
126     tmp=new byte[length];
127     tmp[0]=(byte)0x30; tmp[1]=(byte)0x2c;
128     tmp[1]+=frst; tmp[1]+=scnd;
129     tmp[2]=(byte)0x02; tmp[3]=(byte)0x14;
130     tmp[3]+=frst;
131     System.arraycopy(sig, 0, tmp, 4+frst, 20);
132     tmp[4+tmp[3]]=(byte)0x02; tmp[5+tmp[3]]=(byte)0x14;
133     tmp[5+tmp[3]]+=scnd;
134     System.arraycopy(sig, 20, tmp, 6+tmp[3]+scnd, 20);
135     sig=tmp;
136
137 /*
138     tmp=new byte[sig.length+6];
139     tmp[0]=(byte)0x30; tmp[1]=(byte)0x2c;
140     tmp[2]=(byte)0x02; tmp[3]=(byte)0x14;
141     System.arraycopy(sig, 0, tmp, 4, 20);
142     tmp[24]=(byte)0x02; tmp[25]=(byte)0x14;
143     System.arraycopy(sig, 20, tmp, 26, 20); sig=tmp;
144 */
145     return signature.verify(sig);
146   }
147 }
148
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