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//
// System.Security.Cryptography.DSA.cs class implementation
//
// Authors:
// Thomas Neidhart (tome@sbox.tugraz.at)
// Sebastien Pouliot (sebastien@ximian.com)
//
// Portions (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005, 2008 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Globalization;
using System.Runtime.InteropServices;
using System.Text;
using Mono.Xml;
using Mono.Security;
// References:
// a. FIPS PUB 186-2: Digital Signature Standard (DSS)
// http://csrc.nist.gov/publications/fips/fips186-2/fips186-2-change1.pdf
namespace System.Security.Cryptography {
#if NET_2_0
[ComVisible (true)]
#endif
public abstract class DSA : AsymmetricAlgorithm {
#if NET_2_0
// Constructor visibility fixed in Fx 2.0
protected DSA ()
#else
// LAMESPEC: It says to derive new DSA implemenation from DSA class.
// Well it's aint gonna be easy this way.
// RSA constructor is public
internal DSA ()
#endif
{
}
public static new DSA Create ()
{
return Create ("System.Security.Cryptography.DSA");
}
public static new DSA Create (string algName)
{
return (DSA) CryptoConfig.CreateFromName (algName);
}
public abstract byte[] CreateSignature (byte[] rgbHash);
public abstract DSAParameters ExportParameters (bool includePrivateParameters);
internal void ZeroizePrivateKey (DSAParameters parameters)
{
if (parameters.X != null)
Array.Clear (parameters.X, 0, parameters.X.Length);
}
public override void FromXmlString (string xmlString)
{
if (xmlString == null)
throw new ArgumentNullException ("xmlString");
DSAParameters dsaParams = new DSAParameters ();
try {
dsaParams.P = GetNamedParam (xmlString, "P");
dsaParams.Q = GetNamedParam (xmlString, "Q");
dsaParams.G = GetNamedParam (xmlString, "G");
dsaParams.J = GetNamedParam (xmlString, "J");
dsaParams.Y = GetNamedParam (xmlString, "Y");
dsaParams.X = GetNamedParam (xmlString, "X");
dsaParams.Seed = GetNamedParam (xmlString, "Seed");
byte[] counter = GetNamedParam (xmlString, "PgenCounter");
if (counter != null) {
byte[] counter4b = new byte [4]; // always 4 bytes
Buffer.BlockCopy (counter, 0, counter4b, 0, counter.Length);
dsaParams.Counter = BitConverterLE.ToInt32 (counter4b, 0);
}
ImportParameters (dsaParams);
}
catch {
ZeroizePrivateKey (dsaParams);
throw;
}
finally {
ZeroizePrivateKey (dsaParams);
}
}
public abstract void ImportParameters (DSAParameters parameters);
// note: using SecurityElement.ToXml wouldn't generate the same string as the MS implementation
public override string ToXmlString (bool includePrivateParameters)
{
StringBuilder sb = new StringBuilder ();
DSAParameters dsaParams = ExportParameters (includePrivateParameters);
try {
sb.Append ("<DSAKeyValue>");
sb.Append ("<P>");
sb.Append (Convert.ToBase64String (dsaParams.P));
sb.Append ("</P>");
sb.Append ("<Q>");
sb.Append (Convert.ToBase64String (dsaParams.Q));
sb.Append ("</Q>");
sb.Append ("<G>");
sb.Append (Convert.ToBase64String (dsaParams.G));
sb.Append ("</G>");
sb.Append ("<Y>");
sb.Append (Convert.ToBase64String (dsaParams.Y));
sb.Append( "</Y>");
if (dsaParams.J != null) {
// if J wasn't imported then it's not exported and neither
// is part of the XML output
sb.Append ("<J>");
sb.Append (Convert.ToBase64String (dsaParams.J));
sb.Append ("</J>");
}
if (dsaParams.Seed != null) {
sb.Append ("<Seed>");
sb.Append (Convert.ToBase64String (dsaParams.Seed));
sb.Append ("</Seed>");
sb.Append ("<PgenCounter>");
// the number of bytes is important (no matter == 0x00)
if (dsaParams.Counter != 0) {
byte[] inArr = BitConverterLE.GetBytes (dsaParams.Counter);
int l = inArr.Length;
while (inArr[l-1] == 0x00)
l--;
sb.Append (Convert.ToBase64String (inArr, 0, l));
} else {
sb.Append ("AA=="); // base64 encoded 0
}
sb.Append ("</PgenCounter>");
}
if (dsaParams.X != null) {
sb.Append ("<X>");
sb.Append (Convert.ToBase64String (dsaParams.X));
sb.Append ("</X>");
}
else if (includePrivateParameters) {
#if NET_2_0
throw new ArgumentNullException ("X");
#else
throw new CryptographicException (
Locale.GetText ("Missing private key informations"));
#endif
}
sb.Append ("</DSAKeyValue>");
}
catch {
ZeroizePrivateKey (dsaParams);
throw;
}
return sb.ToString ();
}
public abstract bool VerifySignature (byte[] rgbHash, byte[] rgbSignature);
}
}
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