mcs/class/Mono.Security/Mono.Security.Cryptography/RSAManaged.cs

   1 //
   2 // RSAManaged.cs - Implements the RSA algorithm.
   3 //
   4 // Authors:
   5 //      Sebastien Pouliot (sebastien@ximian.com)
   6 //      Ben Maurer (bmaurer@users.sf.net)
   7 //
   8 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // Portions (C) 2003 Ben Maurer
  10 // Copyright (C) 2004,2006 Novell, Inc (http://www.novell.com)
  11 //
  12 // Key generation translated from Bouncy Castle JCE (http://www.bouncycastle.org/)
  13 // See bouncycastle.txt for license.
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System;
  36 using System.Security.Cryptography;
  37 using System.Text;
  38
  39 using Mono.Math;
  40
  41 // Big chunks of code are coming from the original RSACryptoServiceProvider class.
  42 // The class was refactored to :
  43 // a.   ease integration of new hash algorithm (like MD2, RIPEMD160, ...);
  44 // b.   provide better support for the coming SSL implementation (requires
  45 //      EncryptValue/DecryptValue) with, or without, Mono runtime/corlib;
  46 // c.   provide an alternative RSA implementation for all Windows (like using
  47 //      OAEP without Windows XP).
  48
  49 namespace Mono.Security.Cryptography {
  50
  51 #if INSIDE_CORLIB
  52         internal
  53 #else
  54         public
  55 #endif
  56         class RSAManaged : RSA {
  57
  58                 private const int defaultKeySize = 1024;
  59
  60                 private bool isCRTpossible = false;
  61                 private bool keyBlinding = true;
  62                 private bool keypairGenerated = false;
  63                 private bool m_disposed = false;
  64
  65                 private BigInteger d;
  66                 private BigInteger p;
  67                 private BigInteger q;
  68                 private BigInteger dp;
  69                 private BigInteger dq;
  70                 private BigInteger qInv;
  71                 private BigInteger n;           // modulus
  72                 private BigInteger e;
  73
  74                 public RSAManaged () : this (defaultKeySize)
  75                 {
  76                 }
  77
  78                 public RSAManaged (int keySize)
  79                 {
  80                         LegalKeySizesValue = new KeySizes [1];
  81                         LegalKeySizesValue [0] = new KeySizes (384, 16384, 8);
  82                         base.KeySize = keySize;
  83                 }
  84
  85                 ~RSAManaged ()
  86                 {
  87                         // Zeroize private key
  88                         Dispose (false);
  89                 }
  90
  91                 private void GenerateKeyPair ()
  92                 {
  93                         // p and q values should have a length of half the strength in bits
  94                         int pbitlength = ((KeySize + 1) >> 1);
  95                         int qbitlength = (KeySize - pbitlength);
  96                         const uint uint_e = 17;
  97                         e = uint_e; // fixed
  98
  99                         // generate p, prime and (p-1) relatively prime to e
 100                         for (;;) {
 101                                 p = BigInteger.GeneratePseudoPrime (pbitlength);
 102                                 if (p % uint_e != 1)
 103                                         break;
 104                         }
 105                         // generate a modulus of the required length
 106                         for (;;) {
 107                                 // generate q, prime and (q-1) relatively prime to e,
 108                                 // and not equal to p
 109                                 for (;;) {
 110                                         q = BigInteger.GeneratePseudoPrime (qbitlength);
 111                                         if ((q % uint_e != 1) && (p != q))
 112                                                 break;
 113                                 }
 114
 115                                 // calculate the modulus
 116                                 n = p * q;
 117                                 if (n.BitCount () == KeySize)
 118                                         break;
 119
 120                                 // if we get here our primes aren't big enough, make the largest
 121                                 // of the two p and try again
 122                                 if (p < q)
 123                                         p = q;
 124                         }
 125
 126                         BigInteger pSub1 = (p - 1);
 127                         BigInteger qSub1 = (q - 1);
 128                         BigInteger phi = pSub1 * qSub1;
 129
 130                         // calculate the private exponent
 131                         d = e.ModInverse (phi);
 132
 133                         // calculate the CRT factors
 134                         dp = d % pSub1;
 135                         dq = d % qSub1;
 136                         qInv = q.ModInverse (p);
 137
 138                         keypairGenerated = true;
 139                         isCRTpossible = true;
 140
 141                         if (KeyGenerated != null)
 142                                 KeyGenerated (this, null);
 143                 }
 144
 145                 // overrides from RSA class
 146
 147                 public override int KeySize {
 148                         get {
 149                                 // in case keypair hasn't been (yet) generated
 150                                 if (keypairGenerated) {
 151                                         int ks = n.BitCount ();
 152                                         if ((ks & 7) != 0)
 153                                                 ks = ks + (8 - (ks & 7));
 154                                         return ks;
 155                                 }
 156                                 else
 157                                         return base.KeySize;
 158                         }
 159                 }
 160                 public override string KeyExchangeAlgorithm {
 161                         get { return "RSA-PKCS1-KeyEx"; }
 162                 }
 163
 164                 // note: when (if) we generate a keypair then it will have both
 165                 // the public and private keys
 166                 public bool PublicOnly {
 167                         get { return (keypairGenerated && ((d == null) || (n == null))); }
 168                 }
 169
 170                 public override string SignatureAlgorithm {
 171                         get { return "http://www.w3.org/2000/09/xmldsig#rsa-sha1"; }
 172                 }
 173
 174                 public override byte[] DecryptValue (byte[] rgb)
 175                 {
 176                         if (m_disposed)
 177                                 throw new ObjectDisposedException ("private key");
 178
 179                         // decrypt operation is used for signature
 180                         if (!keypairGenerated)
 181                                 GenerateKeyPair ();
 182
 183                         BigInteger input = new BigInteger (rgb);
 184                         BigInteger r = null;
 185
 186                         // we use key blinding (by default) against timing attacks
 187                         if (keyBlinding) {
 188                                 // x = (r^e * g) mod n
 189                                 // *new* random number (so it's timing is also random)
 190                                 r = BigInteger.GenerateRandom (n.BitCount ());
 191                                 input = r.ModPow (e, n) * input % n;
 192                         }
 193
 194                         BigInteger output;
 195                         // decrypt (which uses the private key) can be
 196                         // optimized by using CRT (Chinese Remainder Theorem)
 197                         if (isCRTpossible) {
 198                                 // m1 = c^dp mod p
 199                                 BigInteger m1 = input.ModPow (dp, p);
 200                                 // m2 = c^dq mod q
 201                                 BigInteger m2 = input.ModPow (dq, q);
 202                                 BigInteger h;
 203                                 if (m2 > m1) {
 204                                         // thanks to benm!
 205                                         h = p - ((m2 - m1) * qInv % p);
 206                                         output = m2 + q * h;
 207                                 } else {
 208                                         // h = (m1 - m2) * qInv mod p
 209                                         h = (m1 - m2) * qInv % p;
 210                                         // m = m2 + q * h;
 211                                         output = m2 + q * h;
 212                                 }
 213                         } else if (!PublicOnly) {
 214                                 // m = c^d mod n
 215                                 output = input.ModPow (d, n);
 216                         } else {
 217                                 throw new CryptographicException (Locale.GetText ("Missing private key to decrypt value."));
 218                         }
 219
 220                         if (keyBlinding) {
 221                                 // Complete blinding
 222                                 // x^e / r mod n
 223                                 output = output * r.ModInverse (n) % n;
 224                                 r.Clear ();
 225                         }
 226
 227                         // it's sometimes possible for the results to be a byte short
 228                         // and this can break some software (see #79502) so we 0x00 pad the result
 229                         byte[] result = GetPaddedValue (output);
 230                         // zeroize values
 231                         input.Clear ();
 232                         output.Clear ();
 233                         return result;
 234                 }
 235
 236                 public override byte[] EncryptValue (byte[] rgb)
 237                 {
 238                         if (m_disposed)
 239                                 throw new ObjectDisposedException ("public key");
 240
 241                         if (!keypairGenerated)
 242                                 GenerateKeyPair ();
 243
 244                         BigInteger input = new BigInteger (rgb);
 245                         BigInteger output = input.ModPow (e, n);
 246                         // it's sometimes possible for the results to be a byte short
 247                         // and this can break some software (see #79502) so we 0x00 pad the result
 248                         byte[] result = GetPaddedValue (output);
 249                         // zeroize value
 250                         input.Clear ();
 251                         output.Clear ();
 252                         return result;
 253                 }
 254
 255                 public override RSAParameters ExportParameters (bool includePrivateParameters)
 256                 {
 257                         if (m_disposed)
 258                                 throw new ObjectDisposedException ("");
 259
 260                         if (!keypairGenerated)
 261                                 GenerateKeyPair ();
 262
 263                         RSAParameters param = new RSAParameters ();
 264                         param.Exponent = e.GetBytes ();
 265                         param.Modulus = n.GetBytes ();
 266                         if (includePrivateParameters) {
 267                                 // some parameters are required for exporting the private key
 268                                 if (d == null)
 269                                         throw new CryptographicException ("Missing private key");
 270                                 param.D = d.GetBytes ();
 271                                 // hack for bugzilla #57941 where D wasn't provided
 272                                 if (param.D.Length != param.Modulus.Length) {
 273                                         byte[] normalizedD = new byte [param.Modulus.Length];
 274                                         Buffer.BlockCopy (param.D, 0, normalizedD, (normalizedD.Length - param.D.Length), param.D.Length);
 275                                         param.D = normalizedD;
 276                                 }
 277                                 // but CRT parameters are optionals
 278                                 if ((p != null) && (q != null) && (dp != null) && (dq != null) && (qInv != null)) {
 279                                         // and we include them only if we have them all
 280                                         param.P = p.GetBytes ();
 281                                         param.Q = q.GetBytes ();
 282                                         param.DP = dp.GetBytes ();
 283                                         param.DQ = dq.GetBytes ();
 284                                         param.InverseQ = qInv.GetBytes ();
 285                                 }
 286                         }
 287                         return param;
 288                 }
 289
 290                 public override void ImportParameters (RSAParameters parameters)
 291                 {
 292                         if (m_disposed)
 293                                 throw new ObjectDisposedException ("");
 294
 295                         // if missing "mandatory" parameters
 296                         if (parameters.Exponent == null)
 297                                 throw new CryptographicException ("Missing Exponent");
 298                         if (parameters.Modulus == null)
 299                                 throw new CryptographicException ("Missing Modulus");
 300
 301                         e = new BigInteger (parameters.Exponent);
 302                         n = new BigInteger (parameters.Modulus);
 303                         // only if the private key is present
 304                         if (parameters.D != null)
 305                                 d = new BigInteger (parameters.D);
 306                         if (parameters.DP != null)
 307                                 dp = new BigInteger (parameters.DP);
 308                         if (parameters.DQ != null)
 309                                 dq = new BigInteger (parameters.DQ);
 310                         if (parameters.InverseQ != null)
 311                                 qInv = new BigInteger (parameters.InverseQ);
 312                         if (parameters.P != null)
 313                                 p = new BigInteger (parameters.P);
 314                         if (parameters.Q != null)
 315                                 q = new BigInteger (parameters.Q);
 316
 317                         // we now have a keypair
 318                         keypairGenerated = true;
 319                         isCRTpossible = ((p != null) && (q != null) && (dp != null) && (dq != null) && (qInv != null));
 320                 }
 321
 322                 protected override void Dispose (bool disposing)
 323                 {
 324                         if (!m_disposed) {
 325                                 // Always zeroize private key
 326                                 if (d != null) {
 327                                         d.Clear ();
 328                                         d = null;
 329                                 }
 330                                 if (p != null) {
 331                                         p.Clear ();
 332                                         p = null;
 333                                 }
 334                                 if (q != null) {
 335                                         q.Clear ();
 336                                         q = null;
 337                                 }
 338                                 if (dp != null) {
 339                                         dp.Clear ();
 340                                         dp = null;
 341                                 }
 342                                 if (dq != null) {
 343                                         dq.Clear ();
 344                                         dq = null;
 345                                 }
 346                                 if (qInv != null) {
 347                                         qInv.Clear ();
 348                                         qInv = null;
 349                                 }
 350
 351                                 if (disposing) {
 352                                         // clear public key
 353                                         if (e != null) {
 354                                                 e.Clear ();
 355                                                 e = null;
 356                                         }
 357                                         if (n != null) {
 358                                                 n.Clear ();
 359                                                 n = null;
 360                                         }
 361                                 }
 362                         }
 363                         // call base class
 364                         // no need as they all are abstract before us
 365                         m_disposed = true;
 366                 }
 367
 368                 public delegate void KeyGeneratedEventHandler (object sender, EventArgs e);
 369
 370                 public event KeyGeneratedEventHandler KeyGenerated;
 371
 372                 public override string ToXmlString (bool includePrivateParameters)
 373                 {
 374                         StringBuilder sb = new StringBuilder ();
 375                         RSAParameters rsaParams = ExportParameters (includePrivateParameters);
 376                         try {
 377                                 sb.Append ("<RSAKeyValue>");
 378
 379                                 sb.Append ("<Modulus>");
 380                                 sb.Append (Convert.ToBase64String (rsaParams.Modulus));
 381                                 sb.Append ("</Modulus>");
 382
 383                                 sb.Append ("<Exponent>");
 384                                 sb.Append (Convert.ToBase64String (rsaParams.Exponent));
 385                                 sb.Append ("</Exponent>");
 386
 387                                 if (includePrivateParameters) {
 388                                         if (rsaParams.P != null) {
 389                                                 sb.Append ("<P>");
 390                                                 sb.Append (Convert.ToBase64String (rsaParams.P));
 391                                                 sb.Append ("</P>");
 392                                         }
 393                                         if (rsaParams.Q != null) {
 394                                                 sb.Append ("<Q>");
 395                                                 sb.Append (Convert.ToBase64String (rsaParams.Q));
 396                                                 sb.Append ("</Q>");
 397                                         }
 398                                         if (rsaParams.DP != null) {
 399                                                 sb.Append ("<DP>");
 400                                                 sb.Append (Convert.ToBase64String (rsaParams.DP));
 401                                                 sb.Append ("</DP>");
 402                                         }
 403                                         if (rsaParams.DQ != null) {
 404                                                 sb.Append ("<DQ>");
 405                                                 sb.Append (Convert.ToBase64String (rsaParams.DQ));
 406                                                 sb.Append ("</DQ>");
 407                                         }
 408                                         if (rsaParams.InverseQ != null) {
 409                                                 sb.Append ("<InverseQ>");
 410                                                 sb.Append (Convert.ToBase64String (rsaParams.InverseQ));
 411                                                 sb.Append ("</InverseQ>");
 412                                         }
 413                                         sb.Append ("<D>");
 414                                         sb.Append (Convert.ToBase64String (rsaParams.D));
 415                                         sb.Append ("</D>");
 416                                 }
 417
 418                                 sb.Append ("</RSAKeyValue>");
 419                         }
 420                         catch {
 421                                 if (rsaParams.P != null)
 422                                         Array.Clear (rsaParams.P, 0, rsaParams.P.Length);
 423                                 if (rsaParams.Q != null)
 424                                         Array.Clear (rsaParams.Q, 0, rsaParams.Q.Length);
 425                                 if (rsaParams.DP != null)
 426                                         Array.Clear (rsaParams.DP, 0, rsaParams.DP.Length);
 427                                 if (rsaParams.DQ != null)
 428                                         Array.Clear (rsaParams.DQ, 0, rsaParams.DQ.Length);
 429                                 if (rsaParams.InverseQ != null)
 430                                         Array.Clear (rsaParams.InverseQ, 0, rsaParams.InverseQ.Length);
 431                                 if (rsaParams.D != null)
 432                                         Array.Clear (rsaParams.D, 0, rsaParams.D.Length);
 433                                 throw;
 434                         }
 435
 436                         return sb.ToString ();
 437                 }
 438
 439                 // internal for Mono 1.0.x in order to preserve public contract
 440                 // they are public for Mono 1.1.x (for 1.2) as the API isn't froze ATM
 441
 442 #if NET_2_0
 443                 public
 444 #else
 445                 internal
 446 #endif
 447                 bool UseKeyBlinding {
 448                         get { return keyBlinding; }
 449                         // you REALLY shoudn't touch this (true is fine ;-)
 450                         set { keyBlinding = value; }
 451                 }
 452
 453 #if NET_2_0
 454                 public
 455 #else
 456                 internal
 457 #endif
 458                 bool IsCrtPossible {
 459                         // either the key pair isn't generated (and will be
 460                         // generated with CRT parameters) or CRT is (or isn't)
 461                         // possible (in case the key was imported)
 462                         get { return (!keypairGenerated || isCRTpossible); }
 463                 }
 464
 465                 private byte[] GetPaddedValue (BigInteger value)
 466                 {
 467                         byte[] result = value.GetBytes ();
 468                         int length = (KeySize >> 3);
 469                         if (result.Length >= length)
 470                                 return result;
 471
 472                         // left-pad 0x00 value on the result (same integer, correct length)
 473                         byte[] padded = new byte[length];
 474                         Buffer.BlockCopy (result, 0, padded, (length - result.Length), result.Length);
 475                         // temporary result may contain decrypted (plaintext) data, clear it
 476                         Array.Clear (result, 0, result.Length);
 477                         return padded;
 478                 }
 479         }
 480 }