source: stable/HeuristicLab.ExtLibs/HeuristicLab.Cecil/0.9.5/Mono.Cecil-0.9.5/Mono.Cecil/Mono.Security.Cryptography/CryptoConvert.cs

//
// CryptoConvert.cs - Crypto Convertion Routines
//
// Author:
//  Sebastien Pouliot  <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2006 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;
using System.Security.Cryptography;

#if !(SILVERLIGHT || READ_ONLY)

namespace Mono.Security.Cryptography {

  static class CryptoConvert {

    static private int ToInt32LE (byte [] bytes, int offset)
    {
      return (bytes [offset+3] << 24) | (bytes [offset+2] << 16) | (bytes [offset+1] << 8) | bytes [offset];
    }

    static private uint ToUInt32LE (byte [] bytes, int offset)
    {
      return (uint)((bytes [offset+3] << 24) | (bytes [offset+2] << 16) | (bytes [offset+1] << 8) | bytes [offset]);
    }

    static private byte[] Trim (byte[] array)
    {
      for (int i=0; i < array.Length; i++) {
        if (array [i] != 0x00) {
          byte[] result = new byte [array.Length - i];
          Buffer.BlockCopy (array, i, result, 0, result.Length);
          return result;
        }
      }
      return null;
    }

    static RSA FromCapiPrivateKeyBlob (byte[] blob, int offset)
    {
      RSAParameters rsap = new RSAParameters ();
      try {
        if ((blob [offset]   != 0x07) ||        // PRIVATEKEYBLOB (0x07)
            (blob [offset+1] != 0x02) ||        // Version (0x02)
            (blob [offset+2] != 0x00) ||        // Reserved (word)
            (blob [offset+3] != 0x00) ||
            (ToUInt32LE (blob, offset+8) != 0x32415352))  // DWORD magic = RSA2
          throw new CryptographicException ("Invalid blob header");

        // ALGID (CALG_RSA_SIGN, CALG_RSA_KEYX, ...)
        // int algId = ToInt32LE (blob, offset+4);

        // DWORD bitlen
        int bitLen = ToInt32LE (blob, offset+12);

        // DWORD public exponent
        byte[] exp = new byte [4];
        Buffer.BlockCopy (blob, offset+16, exp, 0, 4);
        Array.Reverse (exp);
        rsap.Exponent = Trim (exp);

        int pos = offset+20;
        // BYTE modulus[rsapubkey.bitlen/8];
        int byteLen = (bitLen >> 3);
        rsap.Modulus = new byte [byteLen];
        Buffer.BlockCopy (blob, pos, rsap.Modulus, 0, byteLen);
        Array.Reverse (rsap.Modulus);
        pos += byteLen;

        // BYTE prime1[rsapubkey.bitlen/16];
        int byteHalfLen = (byteLen >> 1);
        rsap.P = new byte [byteHalfLen];
        Buffer.BlockCopy (blob, pos, rsap.P, 0, byteHalfLen);
        Array.Reverse (rsap.P);
        pos += byteHalfLen;

        // BYTE prime2[rsapubkey.bitlen/16];
        rsap.Q = new byte [byteHalfLen];
        Buffer.BlockCopy (blob, pos, rsap.Q, 0, byteHalfLen);
        Array.Reverse (rsap.Q);
        pos += byteHalfLen;

        // BYTE exponent1[rsapubkey.bitlen/16];
        rsap.DP = new byte [byteHalfLen];
        Buffer.BlockCopy (blob, pos, rsap.DP, 0, byteHalfLen);
        Array.Reverse (rsap.DP);
        pos += byteHalfLen;

        // BYTE exponent2[rsapubkey.bitlen/16];
        rsap.DQ = new byte [byteHalfLen];
        Buffer.BlockCopy (blob, pos, rsap.DQ, 0, byteHalfLen);
        Array.Reverse (rsap.DQ);
        pos += byteHalfLen;

        // BYTE coefficient[rsapubkey.bitlen/16];
        rsap.InverseQ = new byte [byteHalfLen];
        Buffer.BlockCopy (blob, pos, rsap.InverseQ, 0, byteHalfLen);
        Array.Reverse (rsap.InverseQ);
        pos += byteHalfLen;

        // ok, this is hackish but CryptoAPI support it so...
        // note: only works because CRT is used by default
        // http://bugzilla.ximian.com/show_bug.cgi?id=57941
        rsap.D = new byte [byteLen]; // must be allocated
        if (pos + byteLen + offset <= blob.Length) {
          // BYTE privateExponent[rsapubkey.bitlen/8];
          Buffer.BlockCopy (blob, pos, rsap.D, 0, byteLen);
          Array.Reverse (rsap.D);
        }
      }
      catch (Exception e) {
        throw new CryptographicException ("Invalid blob.", e);
      }

      RSA rsa = null;
      try {
        rsa = RSA.Create ();
        rsa.ImportParameters (rsap);
      }
      catch (CryptographicException ce) {
        // this may cause problem when this code is run under
        // the SYSTEM identity on Windows (e.g. ASP.NET). See
        // http://bugzilla.ximian.com/show_bug.cgi?id=77559
        try {
          CspParameters csp = new CspParameters ();
          csp.Flags = CspProviderFlags.UseMachineKeyStore;
          rsa = new RSACryptoServiceProvider (csp);
          rsa.ImportParameters (rsap);
        }
        catch {
          // rethrow original, not the later, exception if this fails
          throw ce;
        }
      }
      return rsa;
    }

    static RSA FromCapiPublicKeyBlob (byte[] blob, int offset)
    {
      try {
        if ((blob [offset]   != 0x06) ||        // PUBLICKEYBLOB (0x06)
            (blob [offset+1] != 0x02) ||        // Version (0x02)
            (blob [offset+2] != 0x00) ||        // Reserved (word)
            (blob [offset+3] != 0x00) ||
            (ToUInt32LE (blob, offset+8) != 0x31415352))  // DWORD magic = RSA1
          throw new CryptographicException ("Invalid blob header");

        // ALGID (CALG_RSA_SIGN, CALG_RSA_KEYX, ...)
        // int algId = ToInt32LE (blob, offset+4);

        // DWORD bitlen
        int bitLen = ToInt32LE (blob, offset+12);

        // DWORD public exponent
        RSAParameters rsap = new RSAParameters ();
        rsap.Exponent = new byte [3];
        rsap.Exponent [0] = blob [offset+18];
        rsap.Exponent [1] = blob [offset+17];
        rsap.Exponent [2] = blob [offset+16];

        int pos = offset+20;
        // BYTE modulus[rsapubkey.bitlen/8];
        int byteLen = (bitLen >> 3);
        rsap.Modulus = new byte [byteLen];
        Buffer.BlockCopy (blob, pos, rsap.Modulus, 0, byteLen);
        Array.Reverse (rsap.Modulus);

        RSA rsa = null;
        try {
          rsa = RSA.Create ();
          rsa.ImportParameters (rsap);
        }
        catch (CryptographicException) {
          // this may cause problem when this code is run under
          // the SYSTEM identity on Windows (e.g. ASP.NET). See
          // http://bugzilla.ximian.com/show_bug.cgi?id=77559
          CspParameters csp = new CspParameters ();
          csp.Flags = CspProviderFlags.UseMachineKeyStore;
          rsa = new RSACryptoServiceProvider (csp);
          rsa.ImportParameters (rsap);
        }
        return rsa;
      }
      catch (Exception e) {
        throw new CryptographicException ("Invalid blob.", e);
      }
    }

    // PRIVATEKEYBLOB
    // PUBLICKEYBLOB
    static public RSA FromCapiKeyBlob (byte[] blob)
    {
      return FromCapiKeyBlob (blob, 0);
    }

    static public RSA FromCapiKeyBlob (byte[] blob, int offset)
    {
      if (blob == null)
        throw new ArgumentNullException ("blob");
      if (offset >= blob.Length)
        throw new ArgumentException ("blob is too small.");

      switch (blob [offset]) {
        case 0x00:
          // this could be a public key inside an header
          // like "sn -e" would produce
          if (blob [offset + 12] == 0x06) {
            return FromCapiPublicKeyBlob (blob, offset + 12);
          }
          break;
        case 0x06:
          return FromCapiPublicKeyBlob (blob, offset);
        case 0x07:
          return FromCapiPrivateKeyBlob (blob, offset);
      }
      throw new CryptographicException ("Unknown blob format.");
    }
  }
}

#endif