AsymmetricAlgorithm.cs :  » 2.6.4-mono-.net-core » System.Security » System » Security » Cryptography » C# / CSharp Open Source

//
// System.Security.Cryptography.AsymmetricAlgorithm 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;

namespace System.Security.Cryptography{

  [ComVisible (true)]
  public abstract class AsymmetricAlgorithm : IDisposable {

    protected int KeySizeValue;
    protected KeySizes[] LegalKeySizesValue; 

    protected AsymmetricAlgorithm ()
    {
    }
    
    public abstract string KeyExchangeAlgorithm {
      get;
    }
    
    public virtual int KeySize {
      get { return this.KeySizeValue; }
      set {
        if (!KeySizes.IsLegalKeySize (this.LegalKeySizesValue, value))
          throw new CryptographicException (Locale.GetText ("Key size not supported by algorithm."));
        
        this.KeySizeValue = value;
      }
    }

    public virtual KeySizes[] LegalKeySizes {
      get { return this.LegalKeySizesValue; }
    }

    public abstract string SignatureAlgorithm {
      get;
    }

    void IDisposable.Dispose () 
    {
      Dispose (true);
      GC.SuppressFinalize (this);  // Finalization is now unnecessary
    }

    public void Clear () 
    {
      Dispose (false);
    }

    protected abstract void Dispose (bool disposing);

    public abstract void FromXmlString (string xmlString);
    
    public abstract string ToXmlString (bool includePrivateParameters);    
    
    public static AsymmetricAlgorithm Create () 
    {
      return Create ("System.Security.Cryptography.AsymmetricAlgorithm");
    }
  
    public static AsymmetricAlgorithm Create (string algName) 
    {
      return (AsymmetricAlgorithm) CryptoConfig.CreateFromName (algName);
    }

    // parsing helper shared between DSA and RSA
    internal static byte [] GetNamedParam (string xml, string param)
    {
      string start_element = "<" + param + ">";
      int start = xml.IndexOf (start_element);
      if (start == -1)
        return null;

      string end_element = "</" + param + ">";
      int end = xml.IndexOf (end_element);
      if ((end == -1) || (end <= start))
        return null;

      start += start_element.Length;

      string base64 = xml.Substring (start, end - start);
      return Convert.FromBase64String (base64);
    }
  }
}