mcs/class/corlib/Test/System.Security.Cryptography/RSAPKCS1SignatureDeformatterTest.cs

   1 //
   2 // RSAPKCS1SignatureDeformatterTest.cs - NUnit tests for PKCS#1 v.1.5 signature.
   3 //
   4 // Author:
   5 //      Sebastien Pouliot (sebastien@ximian.com)
   6 //
   7 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   8 // Copyright (C) 2004-2006 Novell, Inc (http://www.novell.com)
   9 //
  10
  11 using NUnit.Framework;
  12 using System;
  13 using System.Security.Cryptography;
  14 using System.Text;
  15
  16 namespace MonoTests.System.Security.Cryptography {
  17
  18         [TestFixture]
  19         public class RSAPKCS1SignatureDeformatterTest {
  20
  21                 private static byte[] shaSignature = { 0x51, 0xE1, 0x69, 0xC4, 0x84, 0x0C, 0x33, 0xD9, 0x80, 0xC0, 0xBD, 0x85, 0x87, 0x6E, 0x85, 0x91, 0xB9, 0xD5, 0xB6, 0xE1, 0xAB, 0xD3, 0x06, 0x83, 0xCF, 0x33, 0x56, 0xB9, 0xE6, 0x2C, 0x37, 0xC0, 0x08, 0xFC, 0x81, 0x15, 0xAB, 0x57, 0x80, 0xE4, 0xB9, 0x95, 0x4B, 0xFA, 0x63, 0x13, 0x5E, 0xA9, 0x6E, 0xAB, 0xB0, 0x89, 0xF3, 0xD0, 0xE9, 0xC7, 0xE7, 0xA0, 0xE2, 0xB6, 0x0A, 0xFF, 0x46, 0x2B, 0x8B, 0xC1, 0x4C, 0xEA, 0xDB, 0xEA, 0xD6, 0xF5, 0xA5, 0x2C, 0x8C, 0x1D, 0x57, 0xDF, 0x2D, 0xF0, 0x6B, 0x1D, 0xA9, 0xAE, 0x7F, 0x10, 0x02, 0xE2, 0x05, 0x7E, 0xD2, 0x80, 0xFC, 0x0E, 0x5A, 0xFD, 0xE9, 0xDB, 0x1B, 0xBA, 0xB4, 0xF7, 0x50, 0x88, 0x73, 0x95, 0xBD, 0x3C, 0xCB, 0x33, 0x02, 0xF5, 0x55, 0x10, 0xA6, 0x1B, 0xFD, 0x1D, 0xB1, 0x0E, 0xE3, 0xD0, 0xB7, 0x14, 0x8D, 0x45, 0xC4, 0xF3 };
  22                 private static byte[] md5Signature = { 0xB4, 0xA9, 0xE9, 0x76, 0x04, 0x0E, 0x0E, 0x04, 0xA3, 0x68, 0x9E, 0x50, 0xD1, 0x29, 0x07, 0x22, 0x45, 0x41, 0x72, 0x1F, 0xBE, 0x74, 0x78, 0xDA, 0x5F, 0x22, 0x4B, 0x45, 0xA8, 0x5F, 0x2D, 0xA5, 0x5F, 0x01, 0x84, 0xA7, 0xF3, 0x6E, 0xB8, 0x8B, 0xF3, 0x29, 0xB2, 0x82, 0xE6, 0x5D, 0x1A, 0x98, 0xAE, 0x9C, 0x2E, 0xB0, 0xDD, 0x3F, 0x8D, 0xF9, 0x1C, 0x9E, 0x40, 0x25, 0x01, 0x9F, 0x92, 0x4E, 0xBE, 0x11, 0xE5, 0xE8, 0xE0, 0xF6, 0x3E, 0xDF, 0x8D, 0x1A, 0xC7, 0x26, 0x37, 0xF7, 0x01, 0x95, 0x48, 0xD8, 0x07, 0x4D, 0x0E, 0xDE, 0xB2, 0x76, 0xD1, 0x23, 0xBD, 0x74, 0xE9, 0xC3, 0x63, 0xB3, 0xE7, 0xCE, 0xA2, 0xEA, 0x20, 0x19, 0x1C, 0x4D, 0x8D, 0xBB, 0xAB, 0x6E, 0xB0, 0xD0, 0x08, 0xC2, 0x2B, 0x69, 0xA4, 0xF3, 0xE9, 0x23, 0xAC, 0x93, 0xB2, 0x0F, 0x90, 0x95, 0x6A, 0x66, 0xDC, 0x44 };
  23
  24                 private static RSA rsa;
  25                 private static DSA dsa;
  26
  27                 [SetUp]
  28                 public void SetUp ()
  29                 {
  30                         shaSignature [0] = 0x51;
  31                         md5Signature [0] = 0xB4;
  32
  33                         if (rsa == null)
  34                                 rsa = RSA.Create ();
  35                         if (dsa == null)
  36                                 dsa = DSA.Create ();
  37                 }
  38
  39                 public void AssertEquals (string msg, byte[] array1, byte[] array2)
  40                 {
  41                         AllTests.AssertEquals (msg, array1, array2);
  42                 }
  43
  44                 [Test]
  45                 public void RSAConstructors ()
  46                 {
  47                         RSAPKCS1SignatureDeformatter fmt;
  48                         fmt = new RSAPKCS1SignatureDeformatter ();
  49
  50                         fmt = new RSAPKCS1SignatureDeformatter (rsa);
  51                 }
  52
  53                 [Test]
  54                 [ExpectedException (typeof (ArgumentNullException))]
  55                 public void RSAConstructor_Null ()
  56                 {
  57                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter (null);
  58                 }
  59
  60                 [Test]
  61                 [ExpectedException (typeof (InvalidCastException))]
  62                 public void DSAConstructor ()
  63                 {
  64                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter (dsa);
  65                 }
  66
  67                 [Test]
  68                 public void SetRSAKey ()
  69                 {
  70                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
  71                         fmt.SetKey (rsa);
  72                 }
  73
  74                 [Test]
  75                 [ExpectedException (typeof (InvalidCastException))]
  76                 public void SetDSAKey ()
  77                 {
  78                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
  79                         fmt.SetKey (dsa);
  80                 }
  81
  82                 [Test]
  83                 [ExpectedException (typeof (ArgumentNullException))]
  84                 public void SetNullKey ()
  85                 {
  86                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
  87                         fmt.SetKey (null);
  88                 }
  89
  90                 [Test]
  91                 [ExpectedException (typeof (ArgumentNullException))]
  92                 public void SetNullHashAlgorithm ()
  93                 {
  94                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
  95                         fmt.SetHashAlgorithm (null);
  96                 }
  97
  98                 [Test]
  99                 public void SetInvalidHashAlgorithm ()
 100                 {
 101                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 102                         fmt.SetHashAlgorithm ("MD3");
 103                 }
 104
 105                 [Test]
 106                 public void SetSHA1HashAlgorithm ()
 107                 {
 108                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 109                         fmt.SetHashAlgorithm ("SHA1");
 110                 }
 111
 112                 [Test]
 113                 public void SetMD5HashAlgorithm ()
 114                 {
 115                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 116                         fmt.SetHashAlgorithm ("MD5");
 117                 }
 118
 119                 [Test]
 120                 public void SetSHA256HashAlgorithm ()
 121                 {
 122                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 123                         fmt.SetHashAlgorithm ("SHA256");
 124                 }
 125
 126                 [Test]
 127                 public void SetSHA384HashAlgorithm ()
 128                 {
 129                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 130                         fmt.SetHashAlgorithm ("SHA384");
 131                 }
 132
 133                 [Test]
 134                 public void SetSHA512HashAlgorithm ()
 135                 {
 136                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 137                         fmt.SetHashAlgorithm ("SHA512");
 138                 }
 139
 140                 [Test]
 141                 [ExpectedException (typeof (ArgumentNullException))]
 142                 public void VerifySignatureNullHash ()
 143                 {
 144                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 145                         fmt.SetHashAlgorithm ("SHA1");
 146                         fmt.SetKey (rsa);
 147                         byte[] hash = null;
 148                         byte[] signature = new byte [128];
 149                         fmt.VerifySignature (hash, signature);
 150                 }
 151
 152                 [Test]
 153                 [ExpectedException (typeof (ArgumentNullException))]
 154                 public void VerifySignatureNullSignature ()
 155                 {
 156                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 157                         fmt.SetHashAlgorithm ("SHA1");
 158                         fmt.SetKey (rsa);
 159                         byte[] hash = new byte [20];
 160                         fmt.VerifySignature (hash, null);
 161                 }
 162
 163                 [Test]
 164                 [ExpectedException (typeof (CryptographicUnexpectedOperationException))]
 165                 public void VerifySignatureWithBadHash ()
 166                 {
 167                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 168                         fmt.SetKey (rsa);
 169                         // no hash algorithm
 170                         byte[] hash = new byte [1];
 171                         byte[] signature = new byte [1];
 172                         fmt.VerifySignature (hash, signature);
 173                 }
 174
 175                 [Test]
 176                 public void VerifySHA1SignatureWithNullKey ()
 177                 {
 178                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 179                         fmt.SetHashAlgorithm ("SHA1");
 180                         byte[] hash = new byte [20];
 181                         try {
 182                                 // no key
 183                                 fmt.VerifySignature (hash, shaSignature);
 184                                 Assert.Fail ("VerifySHA1SignatureWithNullKey - Expected CryptographicUnexpectedOperationException but none");
 185                         }
 186                         catch (CryptographicUnexpectedOperationException) {
 187                                 // this was expected
 188                         }
 189                         catch (NullReferenceException) {
 190                                 // this wasn't expected - but that's the result from framework 1.1
 191                         }
 192                         catch (Exception e) {
 193                                 Assert.Fail ("VerifySHA1SignatureWithNullKey - Expected CryptographicUnexpectedOperationException but got: " + e.ToString ());
 194                         }
 195                 }
 196
 197                 private RSAPKCS1SignatureDeformatter GetDefaultDeformatter (string hashName)
 198                 {
 199                         // no need for the private key
 200                         RSA rsa = RSA.Create ();
 201                         rsa.ImportParameters (AllTests.GetRsaKey (false));
 202
 203                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 204                         fmt.SetKey (rsa);
 205                         fmt.SetHashAlgorithm (hashName);
 206                         return fmt;
 207                 }
 208
 209                 [Test]
 210                 public void VerifySHA1SignatureWithRSAKey ()
 211                 {
 212                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("SHA1");
 213                         // good SHA1
 214                         byte[] hash = new byte [20];
 215                         Assert.IsTrue (fmt.VerifySignature (hash, shaSignature), "VerifySignature(SHA1, sign)");
 216                         // bad signature
 217                         shaSignature [0] = (byte) ~shaSignature [0];
 218                         Assert.IsFalse (fmt.VerifySignature (hash, shaSignature), "VerifySignature(SHA1, badSign)");
 219                 }
 220
 221                 [Test]
 222                 [ExpectedException (typeof (CryptographicException))]
 223                 public void VerifySHA1SignatureWithWrongHashLength ()
 224                 {
 225                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("SHA1");
 226                         // wrong SHA1 length
 227                         byte[] hash = new byte [19];
 228                         fmt.VerifySignature (hash, shaSignature);
 229                 }
 230
 231                 [Test]
 232                 public void VerifySHA1SignatureWithWrongSignatureLength ()
 233                 {
 234                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("SHA1");
 235                         // wrong signature length
 236                         byte[] hash = new byte [20];
 237                         byte[] badSignature = new byte [shaSignature.Length-1];
 238                         Assert.IsFalse (fmt.VerifySignature (hash, badSignature), "VerifySignature(SHA1, badSign)");
 239                 }
 240
 241                 [Test]
 242                 public void VerifyMD5SignatureWithRSAKey ()
 243                 {
 244                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 245                         // good MD5
 246                         byte[] hash = new byte [16];
 247                         Assert.IsTrue (fmt.VerifySignature (hash, md5Signature), "VerifySignature(MD5, sign)");
 248                         // bad signature
 249                         md5Signature [0] = (byte) ~md5Signature [0];
 250                         Assert.IsFalse (fmt.VerifySignature (hash, md5Signature), "VerifySignature(MD5, badSign)");
 251                 }
 252
 253                 [Test]
 254                 [ExpectedException (typeof (CryptographicException))]
 255                 public void VerifyMD5SignatureWithWrongHashLength ()
 256                 {
 257                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 258                         // wrong MD5 length
 259                         byte[] hash = new byte [17];
 260                         fmt.VerifySignature (hash, md5Signature);
 261                 }
 262
 263                 [Test]
 264                 public void VerifyMD5SignatureWithWrongSignatureLength ()
 265                 {
 266                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 267                         // wrong signature length
 268                         byte[] hash = new byte [16];
 269                         byte[] badSignature = new byte [md5Signature.Length-1];
 270                         Assert.IsFalse (fmt.VerifySignature (hash, badSignature), "VerifySignature(MD5, badSign)");
 271                 }
 272
 273                 [Test]
 274                 [ExpectedException (typeof (ArgumentNullException))]
 275                 public void VerifySignatureNullHashAlgorithm ()
 276                 {
 277                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 278                         HashAlgorithm hash = null;
 279                         byte[] data = new byte [20];
 280                         // no hash algorithm
 281                         byte[] signature = new byte [1];
 282                         fmt.VerifySignature (hash, signature);
 283                 }
 284
 285                 [Test]
 286                 public void VerifySignatureHashNoKey ()
 287                 {
 288                         RSAPKCS1SignatureDeformatter fmt = new RSAPKCS1SignatureDeformatter ();
 289                         HashAlgorithm hash = SHA1.Create ();
 290                         try {
 291                                 // no key
 292                                 fmt.VerifySignature (hash, shaSignature);
 293                                 Assert.Fail ("VerifySignatureHashNoKey - Expected CryptographicUnexpectedOperationException but none");
 294                         }
 295                         catch (CryptographicUnexpectedOperationException) {
 296                                 // this was expected
 297                         }
 298                         catch (NullReferenceException) {
 299                                 // this wasn't expected - but that's the result from framework 1.1
 300                         }
 301                         catch (Exception e) {
 302                                 Assert.Fail ("VerifySignatureHashNoKey - Expected CryptographicUnexpectedOperationException but got: " + e.ToString ());
 303                         }
 304                 }
 305
 306                 [Test]
 307                 public void VerifySignatureSHA1Hash ()
 308                 {
 309                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("SHA1");
 310                         // good SHA1
 311                         byte[] data = new byte [20];
 312                         HashAlgorithm hash = SHA1.Create ();
 313                         hash.ComputeHash (data);
 314
 315                         byte[] shaSignature = { 0x7C, 0xA0, 0x13, 0xFB, 0xCB, 0x4D, 0x08, 0x02, 0x3C, 0x6B, 0x88, 0xA6, 0x25, 0x43, 0x17, 0x51, 0xA6, 0xA8, 0x8F, 0x5B, 0xAE, 0xC3, 0x57, 0x75, 0x2A, 0x8B, 0xD8, 0xBA, 0xCF, 0x9B, 0xBB, 0x5A, 0xD5, 0xB0, 0x11, 0xF2, 0xA9, 0xCC, 0xB5, 0x22, 0x59, 0xEE, 0x85, 0x49, 0x11, 0xB6, 0x9C, 0x50, 0x61, 0x4A, 0xEC, 0xA3, 0x50, 0x96, 0xE3, 0x2F, 0x1A, 0x6D, 0x9B, 0x6B, 0x6E, 0xC4, 0x50, 0x50, 0x84, 0x29, 0x92, 0x93, 0xE0, 0x0F, 0xCB, 0xBB, 0x61, 0x5D, 0x36, 0x51, 0x1A, 0xBB, 0x73, 0x75, 0x83, 0xEF, 0xDB, 0x4B, 0x2A, 0x38, 0x2C, 0x37, 0x0A, 0x1F, 0x84, 0xE0, 0x9B, 0x24, 0xDF, 0x69, 0x0E, 0x5C, 0xD9, 0xAF, 0x89, 0x72, 0x45, 0x30, 0xA1, 0xDB, 0xA8, 0x22, 0x40, 0x42, 0x07, 0xCC, 0x2A, 0x0E, 0x90, 0x9A, 0x4D, 0xE5, 0x2B, 0x48, 0x86, 0x4D, 0x01, 0x25, 0x23, 0x95, 0xB5, 0xBD };
 316                         Assert.IsTrue (fmt.VerifySignature (hash, shaSignature), "VerifySignature(SHA1, sign)");
 317                         // bad signature
 318                         shaSignature [0] = (byte) ~shaSignature [0];
 319                         Assert.IsFalse (fmt.VerifySignature (hash, shaSignature), "VerifySignature(SHA1, badSign)");
 320                 }
 321
 322                 [Test]
 323                 public void VerifySignatureSHA1HashBadSignatureLength ()
 324                 {
 325                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("SHA1");
 326                         // wrong signature length
 327                         byte[] badSignature = new byte [shaSignature.Length-1];
 328                         HashAlgorithm hash = SHA1.Create ();
 329                         try {
 330                                 fmt.VerifySignature (hash, badSignature);
 331                                 Assert.Fail ("VerifySignatureSHA1HashBadSignatureLength - Expected CryptographicUnexpectedOperationException but none");
 332                         }
 333                         catch (CryptographicUnexpectedOperationException) {
 334                                 // this was expected
 335                         }
 336                         catch (NullReferenceException) {
 337                                 // this wasn't expected - but that's the result from framework 1.1
 338                         }
 339                         catch (Exception e) {
 340                                 Assert.Fail ("VerifySignatureSHA1HashBadSignatureLength - Expected CryptographicUnexpectedOperationException but got: " + e.ToString ());
 341                         }
 342                 }
 343
 344                 [Test]
 345                 public void VerifySignatureMD5Hash ()
 346                 {
 347                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 348                         // good MD5
 349                         byte[] data = new byte [20];
 350                         HashAlgorithm hash = MD5.Create ();
 351                         hash.ComputeHash (data);
 352                         byte[] signature = { 0x0F, 0xD6, 0x16, 0x2C, 0x31, 0xD6, 0xD7, 0xA0, 0xE8, 0xA0, 0x89, 0x53, 0x7B, 0x36, 0x8F, 0x25, 0xA5, 0xF6, 0x4A, 0x0B, 0xD3, 0xB9, 0x9B, 0xC4, 0xAE, 0xDC, 0xD4, 0x58, 0x5C, 0xD9, 0x58, 0x61, 0xE3, 0x66, 0x89, 0xB1, 0x1E, 0x33, 0x88, 0xDF, 0x58, 0xC4, 0x2E, 0xAE, 0xE7, 0x7B, 0x96, 0x61, 0x77, 0x91, 0xBD, 0xBD, 0x99, 0x9E, 0x1C, 0x3E, 0x0A, 0x5C, 0x15, 0x69, 0x00, 0xFA, 0xEE, 0xD7, 0xDC, 0xD2, 0x62, 0xA3, 0x31, 0x6A, 0x33, 0x75, 0xC8, 0x8E, 0x47, 0x5C, 0x1E, 0xD8, 0x91, 0x36, 0x65, 0xF3, 0x67, 0x63, 0xFC, 0x2B, 0x37, 0x7D, 0xE6, 0x2C, 0x2C, 0x09, 0x45, 0xE1, 0x8D, 0x8C, 0x8F, 0xFC, 0x6A, 0x4A, 0xD1, 0x4D, 0x06, 0xF3, 0x79, 0x9F, 0xDB, 0x0F, 0x4B, 0xD1, 0x94, 0x6F, 0xC7, 0xE7, 0x4E, 0x06, 0xDA, 0xDB, 0x2A, 0x51, 0x62, 0xCA, 0x1A, 0x31, 0x51, 0x2B, 0x83, 0xDD };
 353                         Assert.IsTrue (fmt.VerifySignature (hash, signature), "VerifySignature(MD5, sign)");
 354                 }
 355
 356                 [Test]
 357                 public void VerifyBadSignatureMD5Hash ()
 358                 {
 359                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 360                         // bad signature
 361                         byte[] badSignature = new Byte [md5Signature.Length];
 362                         Array.Copy (md5Signature, 0, badSignature, 0, badSignature.Length);
 363                         badSignature[0] = (byte) ~md5Signature [0];
 364                         HashAlgorithm hash = MD5.Create ();
 365                         try {
 366                                 fmt.VerifySignature (hash, md5Signature);
 367                                 Assert.Fail ("VerifyBadSignatureMD5Hash - Expected CryptographicUnexpectedOperationException but none");
 368                         }
 369                         catch (CryptographicUnexpectedOperationException) {
 370                                 // this was expected
 371                         }
 372                         catch (NullReferenceException) {
 373                                 // this wasn't expected - but that's the result from framework 1.1
 374                         }
 375                         catch (Exception e) {
 376                                 Assert.Fail ("VerifyBadSignatureMD5Hash - Expected CryptographicUnexpectedOperationException but got: " + e.ToString ());
 377                         }
 378                 }
 379
 380                 [Test]
 381                 public void VerifySignatureMD5HashBadSignatureLength ()
 382                 {
 383                         RSAPKCS1SignatureDeformatter fmt = GetDefaultDeformatter ("MD5");
 384                         // wrong signature length
 385                         byte[] badSignature = new byte [md5Signature.Length-1];
 386                         HashAlgorithm hash = MD5.Create ();
 387                         try {
 388                                 fmt.VerifySignature (hash, md5Signature);
 389                                 Assert.Fail ("VerifySignatureMD5HashBadSignatureLength - Expected CryptographicUnexpectedOperationException but none");
 390                         }
 391                         catch (CryptographicUnexpectedOperationException) {
 392                                 // this was expected
 393                         }
 394                         catch (NullReferenceException) {
 395                                 // this wasn't expected - but that's the result from framework 1.1
 396                         }
 397                         catch (Exception e) {
 398                                 Assert.Fail ("VerifySignatureMD5HashBadSignatureLength - Expected CryptographicUnexpectedOperationException but got: " + e.ToString ());
 399                         }
 400                 }
 401
 402                 [Test]
 403                 public void VerifySignatureWithoutCallingSetHashAlgorithm ()
 404                 {
 405                         string text = "text to sign";
 406                         RSA rsa = RSA.Create ();
 407                         RSAPKCS1SignatureFormatter fmt = new RSAPKCS1SignatureFormatter (rsa);
 408                         SHA1 hash = SHA1.Create ();
 409                         hash.ComputeHash (Encoding.UTF8.GetBytes (text));
 410                         byte[] signature = fmt.CreateSignature (hash);
 411
 412                         RSAPKCS1SignatureDeformatter def = new RSAPKCS1SignatureDeformatter (rsa);
 413                         Assert.IsTrue (def.VerifySignature (hash, signature), "Signature Ok");
 414                 }
 415         }
 416 }