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

//
// ProtectedData.cs: Protect (encrypt) data without (user involved) key management
//
// Author:
//  Sebastien Pouliot  <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005 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.
//

#if NET_2_0

using System.Runtime.InteropServices;
using System.Security.Permissions;

using Mono.Security.Cryptography;

namespace System.Security.Cryptography{

  // References:
  // a.  Windows Data Protection
  //  http://msdn.microsoft.com/library/en-us/dnsecure/html/windataprotection-dpapi.asp?frame=true

  public sealed class ProtectedData {

    private ProtectedData ()
    {
    }

// FIXME  [DataProtectionPermission (SecurityAction.Demand, ProtectData = true)]
    public static byte[] Protect (byte[] userData, byte[] optionalEntropy, DataProtectionScope scope) 
    {
      if (userData == null)
        throw new ArgumentNullException ("userData");

      // on Windows this is supported only under 2000 and later OS
      Check (scope);

      switch (impl) {
      case DataProtectionImplementation.ManagedProtection:
        try {
          return ManagedProtection.Protect (userData, optionalEntropy, scope);
        }
        catch (Exception e) {
          string msg = Locale.GetText ("Data protection failed.");
          throw new CryptographicException (msg, e);
        }
      case DataProtectionImplementation.Win32CryptoProtect:
        try {
          return NativeDapiProtection.Protect (userData, optionalEntropy, scope);
        }
        catch (Exception e) {
          string msg = Locale.GetText ("Data protection failed.");
          throw new CryptographicException (msg, e);
        }
      default:
        throw new PlatformNotSupportedException ();
      }
    }

// FIXME  [DataProtectionPermission (SecurityAction.Demand, UnprotectData = true)]
    public static byte[] Unprotect (byte[] encryptedData, byte[] optionalEntropy, DataProtectionScope scope) 
    {
      if (encryptedData == null)
        throw new ArgumentNullException ("encryptedData");

      // on Windows this is supported only under 2000 and later OS
      Check (scope);

      switch (impl) {
      case DataProtectionImplementation.ManagedProtection:
        try {
          return ManagedProtection.Unprotect (encryptedData, optionalEntropy, scope);
        }
        catch (Exception e) {
          string msg = Locale.GetText ("Data unprotection failed.");
          throw new CryptographicException (msg, e);
        }
      case DataProtectionImplementation.Win32CryptoProtect:
        try {
          return NativeDapiProtection.Unprotect (encryptedData, optionalEntropy, scope);
        }
        catch (Exception e) {
          string msg = Locale.GetText ("Data unprotection failed.");
          throw new CryptographicException (msg, e);
        }
      default:
        throw new PlatformNotSupportedException ();
      }
    }

    // private stuff

    enum DataProtectionImplementation {
      Unknown,
      Win32CryptoProtect,
      ManagedProtection,
      Unsupported = Int32.MinValue
    }

    private static DataProtectionImplementation impl;

    private static void Detect ()
    {
      OperatingSystem os = Environment.OSVersion;
      switch (os.Platform) {
      case PlatformID.Win32NT:
        Version v = os.Version;
        if (v.Major < 5) {
          impl = DataProtectionImplementation.Unsupported;
        } else {
          // Windows 2000 (5.0) and later
          impl = DataProtectionImplementation.Win32CryptoProtect;
        }
        break;
      case PlatformID.Unix:
        impl = DataProtectionImplementation.ManagedProtection;
        break;
      default:
        impl = DataProtectionImplementation.Unsupported;
        break;
      }
    }

    private static void Check (DataProtectionScope scope)
    {
      if ((scope < DataProtectionScope.CurrentUser) || (scope > DataProtectionScope.LocalMachine)) {
        string msg = Locale.GetText ("Invalid enum value '{0}' for '{1}'.", 
          scope, "DataProtectionScope");
        throw new ArgumentException (msg, "scope");
      }

      switch (impl) {
      case DataProtectionImplementation.Unknown:
        Detect ();
        break;
      case DataProtectionImplementation.Unsupported:
        throw new PlatformNotSupportedException ();
      }
    }
  }
}

#endif