mcs/class/corlib/System.Security.Cryptography/DSACryptoServiceProvider.cs

   1 //
   2 // System.Security.Cryptography.DSACryptoServiceProvider.cs
   3 //
   4 // Authors:
   5 //      Dan Lewis (dihlewis@yahoo.co.uk)
   6 //      Sebastien Pouliot <sebastien@ximian.com>
   7 //      Ben Maurer (bmaurer@users.sf.net)
   8 //
   9 // (C) 2002
  10 // Portions (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
  11 // Portions (C) 2003 Ben Maurer
  12 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.IO;
  35 using System.Globalization;
  36 using System.Runtime.InteropServices;
  37
  38 using Mono.Security.Cryptography;
  39
  40 namespace System.Security.Cryptography {
  41
  42         [ComVisible (true)]
  43         public sealed class DSACryptoServiceProvider : DSA, ICspAsymmetricAlgorithm {
  44                 private const int PROV_DSS_DH = 13;             // from WinCrypt.h
  45
  46                 private KeyPairPersistence store;
  47                 private bool persistKey;
  48                 private bool persisted;
  49
  50                 private bool privateKeyExportable = true;
  51                 private bool m_disposed;
  52
  53                 private DSAManaged dsa;
  54
  55                 // MS implementation generates a keypair everytime a new DSA
  56                 // object is created (unless an existing key container is
  57                 // specified in the CspParameters).
  58                 // However we:
  59                 // (a) often use DSA to import an existing keypair.
  60                 // (b) take a LOT of time to generate the DSA group
  61                 // So we'll generate the keypair only when (and if) it's being
  62                 // used (or exported). This should save us a lot of time (at
  63                 // least in the unit tests).
  64
  65                 public DSACryptoServiceProvider ()
  66                         : this (1024, null)
  67                 {
  68                 }
  69
  70                 public DSACryptoServiceProvider (CspParameters parameters)
  71                         : this (1024, parameters)
  72                 {
  73                 }
  74
  75                 public DSACryptoServiceProvider (int dwKeySize)
  76                         : this (dwKeySize, null)
  77                 {
  78                 }
  79
  80                 public DSACryptoServiceProvider (int dwKeySize, CspParameters parameters)
  81                 {
  82                         LegalKeySizesValue = new KeySizes [1];
  83                         LegalKeySizesValue [0] = new KeySizes (512, 1024, 64);
  84
  85                         // will throw an exception is key size isn't supported
  86                         KeySize = dwKeySize;
  87                         dsa = new DSAManaged (dwKeySize);
  88                         dsa.KeyGenerated += new DSAManaged.KeyGeneratedEventHandler (OnKeyGenerated);
  89
  90                         persistKey = (parameters != null);
  91                         if (parameters == null) {
  92                                 parameters = new CspParameters (PROV_DSS_DH);
  93                                 if (useMachineKeyStore)
  94                                         parameters.Flags |= CspProviderFlags.UseMachineKeyStore;
  95                                 store = new KeyPairPersistence (parameters);
  96                                 // no need to load - it cannot exists
  97                         }
  98                         else {
  99                                 store = new KeyPairPersistence (parameters);
 100                                 store.Load ();
 101                                 if (store.KeyValue != null) {
 102                                         persisted = true;
 103                                         this.FromXmlString (store.KeyValue);
 104                                 }
 105                         }
 106                 }
 107
 108                 ~DSACryptoServiceProvider ()
 109                 {
 110                         Dispose (false);
 111                 }
 112
 113                 // DSA isn't used for key exchange
 114                 public override string KeyExchangeAlgorithm {
 115                         get { return null; }
 116                 }
 117
 118                 public override int KeySize {
 119                         get { return dsa.KeySize; }
 120                 }
 121
 122                 public bool PersistKeyInCsp {
 123                         get { return persistKey; }
 124                         set { persistKey = value; }
 125                 }
 126
 127                 [ComVisible (false)]
 128                 public bool PublicOnly {
 129                         get { return dsa.PublicOnly; }
 130                 }
 131
 132                 public override string SignatureAlgorithm {
 133                         get { return "http://www.w3.org/2000/09/xmldsig#dsa-sha1"; }
 134                 }
 135
 136                 private static bool useMachineKeyStore;
 137
 138                 public static bool UseMachineKeyStore {
 139                         get { return useMachineKeyStore; }
 140                         set { useMachineKeyStore = value; }
 141                 }
 142
 143                 public override DSAParameters ExportParameters (bool includePrivateParameters)
 144                 {
 145                         if ((includePrivateParameters) && (!privateKeyExportable)) {
 146                                 throw new CryptographicException (
 147                                         Locale.GetText ("Cannot export private key"));
 148                         }
 149
 150                         return dsa.ExportParameters (includePrivateParameters);
 151                 }
 152
 153                 public override void ImportParameters (DSAParameters parameters)
 154                 {
 155                         dsa.ImportParameters (parameters);
 156                 }
 157
 158                 public override byte[] CreateSignature (byte[] rgbHash)
 159                 {
 160                         return dsa.CreateSignature (rgbHash);
 161                 }
 162
 163                 public byte[] SignData (byte[] buffer)
 164                 {
 165                         // right now only SHA1 is supported by FIPS186-2
 166                         HashAlgorithm hash = SHA1.Create ();
 167                         byte[] toBeSigned = hash.ComputeHash (buffer);
 168                         return dsa.CreateSignature (toBeSigned);
 169                 }
 170
 171                 public byte[] SignData (byte[] buffer, int offset, int count)
 172                 {
 173                         // right now only SHA1 is supported by FIPS186-2
 174                         HashAlgorithm hash = SHA1.Create ();
 175                         byte[] toBeSigned = hash.ComputeHash (buffer, offset, count);
 176                         return dsa.CreateSignature (toBeSigned);
 177                 }
 178
 179                 public byte[] SignData (Stream inputStream)
 180                 {
 181                         // right now only SHA1 is supported by FIPS186-2
 182                         HashAlgorithm hash = SHA1.Create ();
 183                         byte[] toBeSigned = hash.ComputeHash (inputStream);
 184                         return dsa.CreateSignature (toBeSigned);
 185                 }
 186
 187                 public byte[] SignHash (byte[] rgbHash, string str)
 188                 {
 189                         // right now only SHA1 is supported by FIPS186-2
 190                         if (String.Compare (str, "SHA1", true, CultureInfo.InvariantCulture) != 0) {
 191                                 // not documented
 192                                 throw new CryptographicException (Locale.GetText ("Only SHA1 is supported."));
 193                         }
 194
 195                         return dsa.CreateSignature (rgbHash);
 196                 }
 197
 198                 public bool VerifyData (byte[] rgbData, byte[] rgbSignature)
 199                 {
 200                         // right now only SHA1 is supported by FIPS186-2
 201                         HashAlgorithm hash = SHA1.Create();
 202                         byte[] toBeVerified = hash.ComputeHash (rgbData);
 203                         return dsa.VerifySignature (toBeVerified, rgbSignature);
 204                 }
 205
 206                 // LAMESPEC: MD5 isn't allowed with DSA
 207                 public bool VerifyHash (byte[] rgbHash, string str, byte[] rgbSignature)
 208                 {
 209                         if (str == null)
 210                                 str = "SHA1"; // default value
 211                         if (String.Compare (str, "SHA1", true, CultureInfo.InvariantCulture) != 0) {
 212                                 throw new CryptographicException (Locale.GetText ("Only SHA1 is supported."));
 213                         }
 214
 215                         return dsa.VerifySignature (rgbHash, rgbSignature);
 216                 }
 217
 218                 public override bool VerifySignature (byte[] rgbHash, byte[] rgbSignature)
 219                 {
 220                         return dsa.VerifySignature (rgbHash, rgbSignature);
 221                 }
 222
 223                 protected override void Dispose (bool disposing)
 224                 {
 225                         if (!m_disposed) {
 226                                 // the key is persisted and we do not want it persisted
 227                                 if ((persisted) && (!persistKey)) {
 228                                         store.Remove ();        // delete the container
 229                                 }
 230                                 if (dsa != null)
 231                                         dsa.Clear ();
 232                                 // call base class
 233                                 // no need as they all are abstract before us
 234                                 m_disposed = true;
 235                         }
 236                 }
 237
 238                 // private stuff
 239
 240                 private void OnKeyGenerated (object sender, EventArgs e)
 241                 {
 242                         // the key isn't persisted and we want it persisted
 243                         if ((persistKey) && (!persisted)) {
 244                                 // save the current keypair
 245                                 store.KeyValue = this.ToXmlString (!dsa.PublicOnly);
 246                                 store.Save ();
 247                                 persisted = true;
 248                         }
 249                 }
 250                 // ICspAsymmetricAlgorithm
 251
 252                 [MonoTODO ("call into KeyPairPersistence to get details")]
 253                 [ComVisible (false)]
 254                 public CspKeyContainerInfo CspKeyContainerInfo {
 255                         get { return null; }
 256                 }
 257
 258                 [ComVisible (false)]
 259                 public byte[] ExportCspBlob (bool includePrivateParameters)
 260                 {
 261                         byte[] blob = null;
 262                         if (includePrivateParameters)
 263                                 blob = CryptoConvert.ToCapiPrivateKeyBlob (this);
 264                         else
 265                                 blob = CryptoConvert.ToCapiPublicKeyBlob (this);
 266                         return blob;
 267                 }
 268
 269                 [ComVisible (false)]
 270                 public void ImportCspBlob (byte[] keyBlob)
 271                 {
 272                         if (keyBlob == null)
 273                                 throw new ArgumentNullException ("keyBlob");
 274                         DSA dsa = CryptoConvert.FromCapiKeyBlobDSA (keyBlob);
 275                         if (dsa is DSACryptoServiceProvider) {
 276                                 DSAParameters dsap = dsa.ExportParameters (!(dsa as DSACryptoServiceProvider).PublicOnly);
 277                                 ImportParameters (dsap);
 278                         } else {
 279                                 // we can't know from DSA if the private key is available
 280                                 try {
 281                                         // so we try it...
 282                                         DSAParameters dsap = dsa.ExportParameters (true);
 283                                         ImportParameters (dsap);
 284                                 }
 285                                 catch {
 286                                         // and fall back
 287                                         DSAParameters dsap = dsa.ExportParameters (false);
 288                                         ImportParameters (dsap);
 289                                 }
 290                         }
 291                 }
 292         }
 293 }