class/System/System.Security.Cryptography.X509Certificates/PublicKey.cs

   1 //
   2 // PublicKey.cs - System.Security.Cryptography.PublicKey
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //      Tim Coleman (tim@timcoleman.com)
   7 //
   8 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // Copyright (C) Tim Coleman, 2004
  10 // Copyright (C) 2005 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 #if NET_2_0 && SECURITY_DEP
  33
  34 using Mono.Security;
  35 using Mono.Security.Cryptography;
  36 using MSX = Mono.Security.X509;
  37
  38 namespace System.Security.Cryptography.X509Certificates {
  39
  40         public sealed class PublicKey {
  41
  42                 private const string rsaOid = "1.2.840.113549.1.1.1";
  43                 private const string dsaOid = "1.2.840.10040.4.1";
  44
  45                 private AsymmetricAlgorithm _key;
  46                 private AsnEncodedData _keyValue;
  47                 private AsnEncodedData _params;
  48                 private Oid _oid;
  49
  50                 public PublicKey (Oid oid, AsnEncodedData parameters, AsnEncodedData keyValue)
  51                 {
  52                         if (oid == null)
  53                                 throw new ArgumentNullException ("oid");
  54                         if (parameters == null)
  55                                 throw new ArgumentNullException ("parameters");
  56                         if (keyValue == null)
  57                                 throw new ArgumentNullException ("keyValue");
  58
  59                         _oid = new Oid (oid);
  60                         _params = new AsnEncodedData (parameters);
  61                         _keyValue = new AsnEncodedData (keyValue);
  62                 }
  63
  64                 internal PublicKey (MSX.X509Certificate certificate)
  65                 {
  66                         // note: _key MUSTonly contains the public part of the key
  67                         bool export_required = true;
  68
  69                         if (certificate.KeyAlgorithm == rsaOid) {
  70                                 // shortcut export/import in the case the private key isn't available
  71                                 RSACryptoServiceProvider rcsp = (certificate.RSA as RSACryptoServiceProvider);
  72                                 if ((rcsp != null) && rcsp.PublicOnly) {
  73                                         _key = certificate.RSA;
  74                                         export_required = false;
  75                                 } else {
  76                                         RSAManaged rsam = (certificate.RSA as RSAManaged);
  77                                         if ((rsam != null) && rsam.PublicOnly) {
  78                                                 _key = certificate.RSA;
  79                                                 export_required = false;
  80                                         }
  81                                 }
  82
  83                                 if (export_required) {
  84                                         RSAParameters rsap = certificate.RSA.ExportParameters (false);
  85                                         _key = RSA.Create ();
  86                                         (_key as RSA).ImportParameters (rsap);
  87                                 }
  88                         } else {
  89                                 // shortcut export/import in the case the private key isn't available
  90                                 DSACryptoServiceProvider dcsp = (certificate.DSA as DSACryptoServiceProvider);
  91                                 if ((dcsp != null) && dcsp.PublicOnly) {
  92                                         _key = certificate.DSA;
  93                                         export_required = false;
  94                                 }
  95                                 // note: DSAManaged isn't availablt in Mono.Security due to a bug in Fx 1.x
  96
  97                                 if (export_required) {
  98                                         DSAParameters rsap = certificate.DSA.ExportParameters (false);
  99                                         _key = DSA.Create ();
 100                                         (_key as DSA).ImportParameters (rsap);
 101                                 }
 102                         }
 103
 104                         _oid = new Oid (certificate.KeyAlgorithm);
 105                         _keyValue = new AsnEncodedData (_oid, certificate.PublicKey);
 106                         _params = new AsnEncodedData (_oid, certificate.KeyAlgorithmParameters);
 107                 }
 108
 109                 // properties
 110
 111                 public AsnEncodedData EncodedKeyValue {
 112                         get { return _keyValue; }
 113                 }
 114
 115                 public AsnEncodedData EncodedParameters {
 116                         get { return _params; }
 117                 }
 118
 119                 public AsymmetricAlgorithm Key {
 120                         get {
 121                                 if (_key == null) {
 122                                         switch (_oid.Value) {
 123                                         case rsaOid:
 124                                                 _key = DecodeRSA (_keyValue.RawData);
 125                                                 break;
 126                                         case dsaOid:
 127                                                 _key = DecodeDSA (_keyValue.RawData, _params.RawData);
 128                                                 break;
 129                                         default:
 130                                                 string msg = Locale.GetText ("Cannot decode public key from unknown OID '{0}'.", _oid.Value);
 131                                                 throw new NotSupportedException (msg);
 132                                         }
 133                                 }
 134                                 return _key;
 135                         }
 136                 }
 137
 138                 public Oid Oid {
 139                         get { return _oid; }
 140                 }
 141
 142                 // private stuff
 143
 144                 static private byte[] GetUnsignedBigInteger (byte[] integer)
 145                 {
 146                         if (integer [0] != 0x00)
 147                                 return integer;
 148
 149                         // this first byte is added so we're sure it's an unsigned integer
 150                         // however we can't feed it into RSAParameters or DSAParameters
 151                         int length = integer.Length - 1;
 152                         byte[] uinteger = new byte [length];
 153                         Buffer.BlockCopy (integer, 1, uinteger, 0, length);
 154                         return uinteger;
 155                 }
 156
 157                 static internal DSA DecodeDSA (byte[] rawPublicKey, byte[] rawParameters)
 158                 {
 159                         DSAParameters dsaParams = new DSAParameters ();
 160                         try {
 161                                 // for DSA rawPublicKey contains 1 ASN.1 integer - Y
 162                                 ASN1 pubkey = new ASN1 (rawPublicKey);
 163                                 if (pubkey.Tag != 0x02)
 164                                         throw new CryptographicException (Locale.GetText ("Missing DSA Y integer."));
 165                                 dsaParams.Y = GetUnsignedBigInteger (pubkey.Value);
 166
 167                                 ASN1 param = new ASN1 (rawParameters);
 168                                 if ((param == null) || (param.Tag != 0x30) || (param.Count < 3))
 169                                         throw new CryptographicException (Locale.GetText ("Missing DSA parameters."));
 170                                 if ((param [0].Tag != 0x02) || (param [1].Tag != 0x02) || (param [2].Tag != 0x02))
 171                                         throw new CryptographicException (Locale.GetText ("Invalid DSA parameters."));
 172
 173                                 dsaParams.P = GetUnsignedBigInteger (param [0].Value);
 174                                 dsaParams.Q = GetUnsignedBigInteger (param [1].Value);
 175                                 dsaParams.G = GetUnsignedBigInteger (param [2].Value);
 176                         }
 177                         catch (Exception e) {
 178                                 string msg = Locale.GetText ("Error decoding the ASN.1 structure.");
 179                                 throw new CryptographicException (msg, e);
 180                         }
 181
 182                         DSA dsa = (DSA) new DSACryptoServiceProvider (dsaParams.Y.Length << 3);
 183                         dsa.ImportParameters (dsaParams);
 184                         return dsa;
 185                 }
 186
 187                 static internal RSA DecodeRSA (byte[] rawPublicKey)
 188                 {
 189                         RSAParameters rsaParams = new RSAParameters ();
 190                         try {
 191                                 // for RSA rawPublicKey contains 2 ASN.1 integers
 192                                 // the modulus and the public exponent
 193                                 ASN1 pubkey = new ASN1 (rawPublicKey);
 194                                 if (pubkey.Count == 0)
 195                                         throw new CryptographicException (Locale.GetText ("Missing RSA modulus and exponent."));
 196                                 ASN1 modulus = pubkey [0];
 197                                 if ((modulus == null) || (modulus.Tag != 0x02))
 198                                         throw new CryptographicException (Locale.GetText ("Missing RSA modulus."));
 199                                 ASN1 exponent = pubkey [1];
 200                                 if (exponent.Tag != 0x02)
 201                                         throw new CryptographicException (Locale.GetText ("Missing RSA public exponent."));
 202
 203                                 rsaParams.Modulus = GetUnsignedBigInteger (modulus.Value);
 204                                 rsaParams.Exponent = exponent.Value;
 205                         }
 206                         catch (Exception e) {
 207                                 string msg = Locale.GetText ("Error decoding the ASN.1 structure.");
 208                                 throw new CryptographicException (msg, e);
 209                         }
 210
 211                         int keySize = (rsaParams.Modulus.Length << 3);
 212                         RSA rsa = (RSA) new RSACryptoServiceProvider (keySize);
 213                         rsa.ImportParameters (rsaParams);
 214                         return rsa;
 215                 }
 216         }
 217 }
 218
 219 #endif