2 // System.Security.Cryptography.DSA.cs class implementation
5 // Thomas Neidhart (tome@sbox.tugraz.at)
6 // Sebastien Pouliot (sebastien@ximian.com)
8 // Portions (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
9 // Copyright (C) 2004-2005, 2008 Novell, Inc (http://www.novell.com)
11 // Permission is hereby granted, free of charge, to any person obtaining
12 // a copy of this software and associated documentation files (the
13 // "Software"), to deal in the Software without restriction, including
14 // without limitation the rights to use, copy, modify, merge, publish,
15 // distribute, sublicense, and/or sell copies of the Software, and to
16 // permit persons to whom the Software is furnished to do so, subject to
17 // the following conditions:
19 // The above copyright notice and this permission notice shall be
20 // included in all copies or substantial portions of the Software.
22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 using System.Globalization;
32 using System.Runtime.InteropServices;
39 // a. FIPS PUB 186-2: Digital Signature Standard (DSS)
40 // http://csrc.nist.gov/publications/fips/fips186-2/fips186-2-change1.pdf
42 namespace System.Security.Cryptography {
45 public abstract class DSA : AsymmetricAlgorithm {
47 // Constructor visibility fixed in Fx 2.0
52 public static new DSA Create ()
55 return new System.Security.Cryptography.DSACryptoServiceProvider ();
57 return Create ("System.Security.Cryptography.DSA");
61 public static new DSA Create (string algName)
63 return (DSA) CryptoConfig.CreateFromName (algName);
66 public abstract byte[] CreateSignature (byte[] rgbHash);
68 public abstract DSAParameters ExportParameters (bool includePrivateParameters);
70 internal void ZeroizePrivateKey (DSAParameters parameters)
72 if (parameters.X != null)
73 Array.Clear (parameters.X, 0, parameters.X.Length);
76 public override void FromXmlString (string xmlString)
78 if (xmlString == null)
79 throw new ArgumentNullException ("xmlString");
81 DSAParameters dsaParams = new DSAParameters ();
83 dsaParams.P = GetNamedParam (xmlString, "P");
84 dsaParams.Q = GetNamedParam (xmlString, "Q");
85 dsaParams.G = GetNamedParam (xmlString, "G");
86 dsaParams.J = GetNamedParam (xmlString, "J");
87 dsaParams.Y = GetNamedParam (xmlString, "Y");
88 dsaParams.X = GetNamedParam (xmlString, "X");
89 dsaParams.Seed = GetNamedParam (xmlString, "Seed");
90 byte[] counter = GetNamedParam (xmlString, "PgenCounter");
91 if (counter != null) {
92 byte[] counter4b = new byte [4]; // always 4 bytes
93 Buffer.BlockCopy (counter, 0, counter4b, 0, counter.Length);
94 dsaParams.Counter = BitConverterLE.ToInt32 (counter4b, 0);
96 ImportParameters (dsaParams);
99 ZeroizePrivateKey (dsaParams);
103 ZeroizePrivateKey (dsaParams);
107 public abstract void ImportParameters (DSAParameters parameters);
109 // note: using SecurityElement.ToXml wouldn't generate the same string as the MS implementation
110 public override string ToXmlString (bool includePrivateParameters)
112 StringBuilder sb = new StringBuilder ();
113 DSAParameters dsaParams = ExportParameters (includePrivateParameters);
115 sb.Append ("<DSAKeyValue>");
118 sb.Append (Convert.ToBase64String (dsaParams.P));
122 sb.Append (Convert.ToBase64String (dsaParams.Q));
126 sb.Append (Convert.ToBase64String (dsaParams.G));
130 sb.Append (Convert.ToBase64String (dsaParams.Y));
133 if (dsaParams.J != null) {
134 // if J wasn't imported then it's not exported and neither
135 // is part of the XML output
137 sb.Append (Convert.ToBase64String (dsaParams.J));
141 if (dsaParams.Seed != null) {
142 sb.Append ("<Seed>");
143 sb.Append (Convert.ToBase64String (dsaParams.Seed));
144 sb.Append ("</Seed>");
146 sb.Append ("<PgenCounter>");
147 // the number of bytes is important (no matter == 0x00)
148 if (dsaParams.Counter != 0) {
149 byte[] inArr = BitConverterLE.GetBytes (dsaParams.Counter);
150 int l = inArr.Length;
151 while (inArr[l-1] == 0x00)
154 sb.Append (Convert.ToBase64String (inArr, 0, l));
156 sb.Append ("AA=="); // base64 encoded 0
158 sb.Append ("</PgenCounter>");
161 if (dsaParams.X != null) {
163 sb.Append (Convert.ToBase64String (dsaParams.X));
166 else if (includePrivateParameters) {
167 throw new ArgumentNullException ("X");
170 sb.Append ("</DSAKeyValue>");
173 ZeroizePrivateKey (dsaParams);
177 return sb.ToString ();
180 public abstract bool VerifySignature (byte[] rgbHash, byte[] rgbSignature);