Novacoin/ScriptCode.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Text;
   5
   6 using System.Numerics;
   7
   8 // using Org.BouncyCastle.Math;
   9
  10 namespace Novacoin
  11 {
  12     /// <summary>
  13     /// Script opcodes
  14     /// </summary>
  15     public enum instruction
  16     {
  17         // push value
  18         OP_0 = 0x00,
  19         OP_FALSE = OP_0,
  20         OP_PUSHDATA1 = 0x4c,
  21         OP_PUSHDATA2 = 0x4d,
  22         OP_PUSHDATA4 = 0x4e,
  23         OP_1NEGATE = 0x4f,
  24         OP_RESERVED = 0x50,
  25         OP_1 = 0x51,
  26         OP_TRUE = OP_1,
  27         OP_2 = 0x52,
  28         OP_3 = 0x53,
  29         OP_4 = 0x54,
  30         OP_5 = 0x55,
  31         OP_6 = 0x56,
  32         OP_7 = 0x57,
  33         OP_8 = 0x58,
  34         OP_9 = 0x59,
  35         OP_10 = 0x5a,
  36         OP_11 = 0x5b,
  37         OP_12 = 0x5c,
  38         OP_13 = 0x5d,
  39         OP_14 = 0x5e,
  40         OP_15 = 0x5f,
  41         OP_16 = 0x60,
  42
  43         // control
  44         OP_NOP = 0x61,
  45         OP_VER = 0x62,
  46         OP_IF = 0x63,
  47         OP_NOTIF = 0x64,
  48         OP_VERIF = 0x65,
  49         OP_VERNOTIF = 0x66,
  50         OP_ELSE = 0x67,
  51         OP_ENDIF = 0x68,
  52         OP_VERIFY = 0x69,
  53         OP_RETURN = 0x6a,
  54
  55         // stack ops
  56         OP_TOALTSTACK = 0x6b,
  57         OP_FROMALTSTACK = 0x6c,
  58         OP_2DROP = 0x6d,
  59         OP_2DUP = 0x6e,
  60         OP_3DUP = 0x6f,
  61         OP_2OVER = 0x70,
  62         OP_2ROT = 0x71,
  63         OP_2SWAP = 0x72,
  64         OP_IFDUP = 0x73,
  65         OP_DEPTH = 0x74,
  66         OP_DROP = 0x75,
  67         OP_DUP = 0x76,
  68         OP_NIP = 0x77,
  69         OP_OVER = 0x78,
  70         OP_PICK = 0x79,
  71         OP_ROLL = 0x7a,
  72         OP_ROT = 0x7b,
  73         OP_SWAP = 0x7c,
  74         OP_TUCK = 0x7d,
  75
  76         // splice ops
  77         OP_CAT = 0x7e,
  78         OP_SUBSTR = 0x7f,
  79         OP_LEFT = 0x80,
  80         OP_RIGHT = 0x81,
  81         OP_SIZE = 0x82,
  82
  83         // bit logic
  84         OP_INVERT = 0x83,
  85         OP_AND = 0x84,
  86         OP_OR = 0x85,
  87         OP_XOR = 0x86,
  88         OP_EQUAL = 0x87,
  89         OP_EQUALVERIFY = 0x88,
  90         OP_RESERVED1 = 0x89,
  91         OP_RESERVED2 = 0x8a,
  92
  93         // numeric
  94         OP_1ADD = 0x8b,
  95         OP_1SUB = 0x8c,
  96         OP_2MUL = 0x8d,
  97         OP_2DIV = 0x8e,
  98         OP_NEGATE = 0x8f,
  99         OP_ABS = 0x90,
 100         OP_NOT = 0x91,
 101         OP_0NOTEQUAL = 0x92,
 102
 103         OP_ADD = 0x93,
 104         OP_SUB = 0x94,
 105         OP_MUL = 0x95,
 106         OP_DIV = 0x96,
 107         OP_MOD = 0x97,
 108         OP_LSHIFT = 0x98,
 109         OP_RSHIFT = 0x99,
 110
 111         OP_BOOLAND = 0x9a,
 112         OP_BOOLOR = 0x9b,
 113         OP_NUMEQUAL = 0x9c,
 114         OP_NUMEQUALVERIFY = 0x9d,
 115         OP_NUMNOTEQUAL = 0x9e,
 116         OP_LESSTHAN = 0x9f,
 117         OP_GREATERTHAN = 0xa0,
 118         OP_LESSTHANOREQUAL = 0xa1,
 119         OP_GREATERTHANOREQUAL = 0xa2,
 120         OP_MIN = 0xa3,
 121         OP_MAX = 0xa4,
 122
 123         OP_WITHIN = 0xa5,
 124
 125         // crypto
 126         OP_RIPEMD160 = 0xa6,
 127         OP_SHA1 = 0xa7,
 128         OP_SHA256 = 0xa8,
 129         OP_HASH160 = 0xa9,
 130         OP_HASH256 = 0xaa,
 131         OP_CODESEPARATOR = 0xab,
 132         OP_CHECKSIG = 0xac,
 133         OP_CHECKSIGVERIFY = 0xad,
 134         OP_CHECKMULTISIG = 0xae,
 135         OP_CHECKMULTISIGVERIFY = 0xaf,
 136
 137         // expansion
 138         OP_NOP1 = 0xb0,
 139         OP_NOP2 = 0xb1,
 140         OP_NOP3 = 0xb2,
 141         OP_NOP4 = 0xb3,
 142         OP_NOP5 = 0xb4,
 143         OP_NOP6 = 0xb5,
 144         OP_NOP7 = 0xb6,
 145         OP_NOP8 = 0xb7,
 146         OP_NOP9 = 0xb8,
 147         OP_NOP10 = 0xb9,
 148
 149         // template matching params
 150         OP_SMALLDATA = 0xf9,
 151         OP_SMALLINTEGER = 0xfa,
 152         OP_PUBKEYS = 0xfb,
 153         OP_PUBKEYHASH = 0xfd,
 154         OP_PUBKEY = 0xfe,
 155
 156         OP_INVALIDOPCODE = 0xff,
 157     };
 158
 159     /// <summary>
 160     /// Transaction output types.
 161     /// </summary>
 162     public enum txnouttype
 163     {
 164         TX_NONSTANDARD,
 165
 166         // 'standard' transaction types:
 167         TX_PUBKEY,
 168         TX_PUBKEYHASH,
 169         TX_SCRIPTHASH,
 170         TX_MULTISIG,
 171         TX_NULL_DATA,
 172     };
 173
 174     /// <summary>
 175     /// Signature hash types/flags
 176     /// </summary>
 177     public enum sigflag
 178     {
 179         SIGHASH_ALL = 1,
 180         SIGHASH_NONE = 2,
 181         SIGHASH_SINGLE = 3,
 182         SIGHASH_ANYONECANPAY = 0x80,
 183     };
 184
 185     /** Script verification flags */
 186     public enum scriptflag
 187     {
 188         SCRIPT_VERIFY_NONE = 0,
 189         SCRIPT_VERIFY_P2SH = (1 << 0), // evaluate P2SH (BIP16) subscripts
 190         SCRIPT_VERIFY_STRICTENC = (1 << 1), // enforce strict conformance to DER and SEC2 for signatures and pubkeys
 191         SCRIPT_VERIFY_LOW_S = (1 << 2), // enforce low S values in signatures (depends on STRICTENC)
 192         SCRIPT_VERIFY_NOCACHE = (1 << 3), // do not store results in signature cache (but do query it)
 193         SCRIPT_VERIFY_NULLDUMMY = (1 << 4), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
 194     };
 195
 196     public static class ScriptCode
 197     {
 198         public static string GetTxnOutputType(txnouttype t)
 199         {
 200             switch (t)
 201             {
 202                 case txnouttype.TX_NONSTANDARD: return "nonstandard";
 203                 case txnouttype.TX_PUBKEY: return "pubkey";
 204                 case txnouttype.TX_PUBKEYHASH: return "pubkeyhash";
 205                 case txnouttype.TX_SCRIPTHASH: return "scripthash";
 206                 case txnouttype.TX_MULTISIG: return "multisig";
 207                 case txnouttype.TX_NULL_DATA: return "nulldata";
 208             }
 209             return string.Empty;
 210         }
 211
 212         /// <summary>
 213         /// Get the name of supplied opcode
 214         /// </summary>
 215         /// <param name="opcode">Opcode</param>
 216         /// <returns>Opcode name</returns>
 217         public static string GetOpName(instruction opcode)
 218         {
 219             switch (opcode)
 220             {
 221                 // push value
 222                 case instruction.OP_0:
 223                     return "OP_0";
 224                 case instruction.OP_PUSHDATA1:
 225                     return "OP_PUSHDATA1";
 226                 case instruction.OP_PUSHDATA2:
 227                     return "OP_PUSHDATA2";
 228                 case instruction.OP_PUSHDATA4:
 229                     return "OP_PUSHDATA4";
 230                 case instruction.OP_1NEGATE:
 231                     return "OP_1NEGATE";
 232                 case instruction.OP_RESERVED:
 233                     return "OP_RESERVED";
 234                 case instruction.OP_1:
 235                     return "OP_1";
 236                 case instruction.OP_2:
 237                     return "OP_2";
 238                 case instruction.OP_3:
 239                     return "OP_3";
 240                 case instruction.OP_4:
 241                     return "OP_4";
 242                 case instruction.OP_5:
 243                     return "OP_5";
 244                 case instruction.OP_6:
 245                     return "OP_6";
 246                 case instruction.OP_7:
 247                     return "OP_7";
 248                 case instruction.OP_8:
 249                     return "OP_8";
 250                 case instruction.OP_9:
 251                     return "OP_9";
 252                 case instruction.OP_10:
 253                     return "OP_10";
 254                 case instruction.OP_11:
 255                     return "OP_11";
 256                 case instruction.OP_12:
 257                     return "OP_12";
 258                 case instruction.OP_13:
 259                     return "OP_13";
 260                 case instruction.OP_14:
 261                     return "OP_14";
 262                 case instruction.OP_15:
 263                     return "OP_15";
 264                 case instruction.OP_16:
 265                     return "OP_16";
 266
 267                 // control
 268                 case instruction.OP_NOP:
 269                     return "OP_NOP";
 270                 case instruction.OP_VER:
 271                     return "OP_VER";
 272                 case instruction.OP_IF:
 273                     return "OP_IF";
 274                 case instruction.OP_NOTIF:
 275                     return "OP_NOTIF";
 276                 case instruction.OP_VERIF:
 277                     return "OP_VERIF";
 278                 case instruction.OP_VERNOTIF:
 279                     return "OP_VERNOTIF";
 280                 case instruction.OP_ELSE:
 281                     return "OP_ELSE";
 282                 case instruction.OP_ENDIF:
 283                     return "OP_ENDIF";
 284                 case instruction.OP_VERIFY:
 285                     return "OP_VERIFY";
 286                 case instruction.OP_RETURN:
 287                     return "OP_RETURN";
 288
 289                 // stack ops
 290                 case instruction.OP_TOALTSTACK:
 291                     return "OP_TOALTSTACK";
 292                 case instruction.OP_FROMALTSTACK:
 293                     return "OP_FROMALTSTACK";
 294                 case instruction.OP_2DROP:
 295                     return "OP_2DROP";
 296                 case instruction.OP_2DUP:
 297                     return "OP_2DUP";
 298                 case instruction.OP_3DUP:
 299                     return "OP_3DUP";
 300                 case instruction.OP_2OVER:
 301                     return "OP_2OVER";
 302                 case instruction.OP_2ROT:
 303                     return "OP_2ROT";
 304                 case instruction.OP_2SWAP:
 305                     return "OP_2SWAP";
 306                 case instruction.OP_IFDUP:
 307                     return "OP_IFDUP";
 308                 case instruction.OP_DEPTH:
 309                     return "OP_DEPTH";
 310                 case instruction.OP_DROP:
 311                     return "OP_DROP";
 312                 case instruction.OP_DUP:
 313                     return "OP_DUP";
 314                 case instruction.OP_NIP:
 315                     return "OP_NIP";
 316                 case instruction.OP_OVER:
 317                     return "OP_OVER";
 318                 case instruction.OP_PICK:
 319                     return "OP_PICK";
 320                 case instruction.OP_ROLL:
 321                     return "OP_ROLL";
 322                 case instruction.OP_ROT:
 323                     return "OP_ROT";
 324                 case instruction.OP_SWAP:
 325                     return "OP_SWAP";
 326                 case instruction.OP_TUCK:
 327                     return "OP_TUCK";
 328
 329                 // splice ops
 330                 case instruction.OP_CAT:
 331                     return "OP_CAT";
 332                 case instruction.OP_SUBSTR:
 333                     return "OP_SUBSTR";
 334                 case instruction.OP_LEFT:
 335                     return "OP_LEFT";
 336                 case instruction.OP_RIGHT:
 337                     return "OP_RIGHT";
 338                 case instruction.OP_SIZE:
 339                     return "OP_SIZE";
 340
 341                 // bit logic
 342                 case instruction.OP_INVERT:
 343                     return "OP_INVERT";
 344                 case instruction.OP_AND:
 345                     return "OP_AND";
 346                 case instruction.OP_OR:
 347                     return "OP_OR";
 348                 case instruction.OP_XOR:
 349                     return "OP_XOR";
 350                 case instruction.OP_EQUAL:
 351                     return "OP_EQUAL";
 352                 case instruction.OP_EQUALVERIFY:
 353                     return "OP_EQUALVERIFY";
 354                 case instruction.OP_RESERVED1:
 355                     return "OP_RESERVED1";
 356                 case instruction.OP_RESERVED2:
 357                     return "OP_RESERVED2";
 358
 359                 // numeric
 360                 case instruction.OP_1ADD:
 361                     return "OP_1ADD";
 362                 case instruction.OP_1SUB:
 363                     return "OP_1SUB";
 364                 case instruction.OP_2MUL:
 365                     return "OP_2MUL";
 366                 case instruction.OP_2DIV:
 367                     return "OP_2DIV";
 368                 case instruction.OP_NEGATE:
 369                     return "OP_NEGATE";
 370                 case instruction.OP_ABS:
 371                     return "OP_ABS";
 372                 case instruction.OP_NOT:
 373                     return "OP_NOT";
 374                 case instruction.OP_0NOTEQUAL:
 375                     return "OP_0NOTEQUAL";
 376                 case instruction.OP_ADD:
 377                     return "OP_ADD";
 378                 case instruction.OP_SUB:
 379                     return "OP_SUB";
 380                 case instruction.OP_MUL:
 381                     return "OP_MUL";
 382                 case instruction.OP_DIV:
 383                     return "OP_DIV";
 384                 case instruction.OP_MOD:
 385                     return "OP_MOD";
 386                 case instruction.OP_LSHIFT:
 387                     return "OP_LSHIFT";
 388                 case instruction.OP_RSHIFT:
 389                     return "OP_RSHIFT";
 390                 case instruction.OP_BOOLAND:
 391                     return "OP_BOOLAND";
 392                 case instruction.OP_BOOLOR:
 393                     return "OP_BOOLOR";
 394                 case instruction.OP_NUMEQUAL:
 395                     return "OP_NUMEQUAL";
 396                 case instruction.OP_NUMEQUALVERIFY:
 397                     return "OP_NUMEQUALVERIFY";
 398                 case instruction.OP_NUMNOTEQUAL:
 399                     return "OP_NUMNOTEQUAL";
 400                 case instruction.OP_LESSTHAN:
 401                     return "OP_LESSTHAN";
 402                 case instruction.OP_GREATERTHAN:
 403                     return "OP_GREATERTHAN";
 404                 case instruction.OP_LESSTHANOREQUAL:
 405                     return "OP_LESSTHANOREQUAL";
 406                 case instruction.OP_GREATERTHANOREQUAL:
 407                     return "OP_GREATERTHANOREQUAL";
 408                 case instruction.OP_MIN:
 409                     return "OP_MIN";
 410                 case instruction.OP_MAX:
 411                     return "OP_MAX";
 412                 case instruction.OP_WITHIN:
 413                     return "OP_WITHIN";
 414
 415                 // crypto
 416                 case instruction.OP_RIPEMD160:
 417                     return "OP_RIPEMD160";
 418                 case instruction.OP_SHA1:
 419                     return "OP_SHA1";
 420                 case instruction.OP_SHA256:
 421                     return "OP_SHA256";
 422                 case instruction.OP_HASH160:
 423                     return "OP_HASH160";
 424                 case instruction.OP_HASH256:
 425                     return "OP_HASH256";
 426                 case instruction.OP_CODESEPARATOR:
 427                     return "OP_CODESEPARATOR";
 428                 case instruction.OP_CHECKSIG:
 429                     return "OP_CHECKSIG";
 430                 case instruction.OP_CHECKSIGVERIFY:
 431                     return "OP_CHECKSIGVERIFY";
 432                 case instruction.OP_CHECKMULTISIG:
 433                     return "OP_CHECKMULTISIG";
 434                 case instruction.OP_CHECKMULTISIGVERIFY:
 435                     return "OP_CHECKMULTISIGVERIFY";
 436
 437                 // expansion
 438                 case instruction.OP_NOP1:
 439                     return "OP_NOP1";
 440                 case instruction.OP_NOP2:
 441                     return "OP_NOP2";
 442                 case instruction.OP_NOP3:
 443                     return "OP_NOP3";
 444                 case instruction.OP_NOP4:
 445                     return "OP_NOP4";
 446                 case instruction.OP_NOP5:
 447                     return "OP_NOP5";
 448                 case instruction.OP_NOP6:
 449                     return "OP_NOP6";
 450                 case instruction.OP_NOP7:
 451                     return "OP_NOP7";
 452                 case instruction.OP_NOP8:
 453                     return "OP_NOP8";
 454                 case instruction.OP_NOP9:
 455                     return "OP_NOP9";
 456                 case instruction.OP_NOP10:
 457                     return "OP_NOP10";
 458
 459                 // template matching params
 460                 case instruction.OP_PUBKEYHASH:
 461                     return "OP_PUBKEYHASH";
 462                 case instruction.OP_PUBKEY:
 463                     return "OP_PUBKEY";
 464                 case instruction.OP_SMALLDATA:
 465                     return "OP_SMALLDATA";
 466
 467                 case instruction.OP_INVALIDOPCODE:
 468                     return "OP_INVALIDOPCODE";
 469                 default:
 470                     return "OP_UNKNOWN";
 471             }
 472         }
 473
 474         /// <summary>
 475         /// Get next opcode from passed list of bytes and extract push arguments if there are some.
 476         /// </summary>
 477         /// <param name="codeBytes">ByteQueue reference.</param>
 478         /// <param name="opcodeRet">Found opcode.</param>
 479         /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
 480         /// <returns>Result of operation</returns>
 481         public static bool GetOp(ref ByteQueue codeBytes, out instruction opcodeRet, out IEnumerable<byte> bytesRet)
 482         {
 483             bytesRet = new List<byte>();
 484             opcodeRet = instruction.OP_INVALIDOPCODE;
 485
 486             instruction opcode;
 487
 488             try
 489             {
 490                 // Read instruction
 491                 opcode = (instruction)codeBytes.Get();
 492             }
 493             catch (ByteQueueException)
 494             {
 495                 // No instruction found there
 496                 return false;
 497             }
 498
 499             // Immediate operand
 500             if (opcode <= instruction.OP_PUSHDATA4)
 501             {
 502                 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
 503
 504                 try
 505                 {
 506                     if (opcode < instruction.OP_PUSHDATA1)
 507                     {
 508                         // Zero value opcodes (OP_0, OP_FALSE)
 509                         szBytes[3] = (byte)opcode;
 510                     }
 511                     else if (opcode == instruction.OP_PUSHDATA1)
 512                     {
 513                         // The next byte contains the number of bytes to be pushed onto the stack,
 514                         //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
 515                         szBytes[3] = (byte)codeBytes.Get();
 516                     }
 517                     else if (opcode == instruction.OP_PUSHDATA2)
 518                     {
 519                         // The next two bytes contain the number of bytes to be pushed onto the stack,
 520                         //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
 521                         codeBytes.Get(2).CopyTo(szBytes, 2);
 522                     }
 523                     else if (opcode == instruction.OP_PUSHDATA4)
 524                     {
 525                         // The next four bytes contain the number of bytes to be pushed onto the stack,
 526                         //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
 527                         szBytes = codeBytes.Get(4);
 528                     }
 529                 }
 530                 catch (ByteQueueException)
 531                 {
 532                     // Unable to read operand length
 533                     return false;
 534                 }
 535
 536                 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
 537
 538                 if (nSize > 0)
 539                 {
 540                     // If nSize is greater than zero then there is some data available
 541                     try
 542                     {
 543                         // Read found number of bytes into list of OP_PUSHDATAn arguments.
 544                         bytesRet = codeBytes.GetEnumerable(nSize);
 545                     }
 546                     catch (ByteQueueException)
 547                     {
 548                         // Unable to read data
 549                         return false;
 550                     }
 551                 }
 552             }
 553
 554             opcodeRet = opcode;
 555
 556             return true;
 557         }
 558
 559         /// <summary>
 560         /// Convert value bytes into readable representation.
 561         ///
 562         /// If list lengh is equal or lesser than 4 bytes then bytes are interpreted as integer value. Otherwise you will get hex representation of supplied data.
 563         /// </summary>
 564         /// <param name="bytes">Collection of value bytes.</param>
 565         /// <returns>Formatted value.</returns>
 566         public static string ValueString(IEnumerable<byte> bytes)
 567         {
 568             StringBuilder sb = new StringBuilder();
 569
 570             if (bytes.Count() <= 4)
 571             {
 572                 byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
 573                 bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());
 574
 575                 sb.Append(Interop.BEBytesToUInt32(valueBytes));
 576             }
 577             else
 578             {
 579                 return Interop.ToHex(bytes);
 580             }
 581
 582             return sb.ToString();
 583         }
 584
 585         /// <summary>
 586         /// Convert list of stack items into human readable representation.
 587         /// </summary>
 588         /// <param name="stackList">List of stack items.</param>
 589         /// <returns>Formatted value.</returns>
 590         public static string StackString(IList<IList<byte>> stackList)
 591         {
 592             StringBuilder sb = new StringBuilder();
 593             foreach (IList<byte> bytesList in stackList)
 594             {
 595                 sb.Append(ValueString(bytesList));
 596             }
 597
 598             return sb.ToString();
 599         }
 600
 601         /// <summary>
 602         /// Decode instruction to integer value
 603         /// </summary>
 604         /// <param name="opcode">Small integer opcode (OP_1_NEGATE and OP_0 - OP_16)</param>
 605         /// <returns>Small integer</returns>
 606         public static int DecodeOP_N(instruction opcode, bool AllowNegate = false)
 607         {
 608             if (AllowNegate && opcode == instruction.OP_1NEGATE)
 609             {
 610                 return -1;
 611             }
 612
 613             if (opcode == instruction.OP_0)
 614             {
 615                 return 0;
 616             }
 617
 618             // Only OP_n opcodes are supported, throw exception otherwise.
 619             if (opcode < instruction.OP_1 || opcode > instruction.OP_16)
 620             {
 621                 throw new Exception("Invalid integer instruction.");
 622             }
 623
 624             return (int)opcode - (int)(instruction.OP_1 - 1);
 625         }
 626
 627         /// <summary>
 628         /// Converts integer into instruction
 629         /// </summary>
 630         /// <param name="n">Small integer from the range of -1 up to 16.</param>
 631         /// <returns>Corresponding opcode.</returns>
 632         public static instruction EncodeOP_N(int n, bool allowNegate = false)
 633         {
 634             if (allowNegate && n == -1)
 635             {
 636                 return instruction.OP_1NEGATE;
 637             }
 638
 639             if (n == 0)
 640             {
 641                 return instruction.OP_0;
 642             }
 643
 644             // The n value must be in the range of 0 to 16.
 645             if (n < 0 || n > 16)
 646                 throw new Exception("Invalid integer value.");
 647             return (instruction.OP_1 + n - 1);
 648         }
 649
 650         public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
 651         {
 652             switch (t)
 653             {
 654                 case txnouttype.TX_NONSTANDARD:
 655                     return -1;
 656                 case txnouttype.TX_NULL_DATA:
 657                     return 1;
 658                 case txnouttype.TX_PUBKEY:
 659                     return 1;
 660                 case txnouttype.TX_PUBKEYHASH:
 661                     return 2;
 662                 case txnouttype.TX_MULTISIG:
 663                     if (solutions.Count() < 1 || solutions.First().Count() < 1)
 664                         return -1;
 665                     return solutions.First().First() + 1;
 666                 case txnouttype.TX_SCRIPTHASH:
 667                     return 1; // doesn't include args needed by the script
 668             }
 669             return -1;
 670         }
 671
 672         /// <summary>
 673         /// Is it a standart type of scriptPubKey?
 674         /// </summary>
 675         /// <param name="scriptPubKey">CScript instance</param>
 676         /// <param name="whichType">utut type</param>
 677         /// <returns>Checking result</returns>
 678         public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
 679         {
 680             IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();
 681
 682             if (!Solver(scriptPubKey, out whichType, out solutions))
 683             {
 684                 // No solutions found
 685                 return false;
 686             }
 687
 688             if (whichType == txnouttype.TX_MULTISIG)
 689             {
 690                 // Additional verification of OP_CHECKMULTISIG arguments
 691                 byte m = solutions.First().First();
 692                 byte n = solutions.Last().First();
 693
 694                 // Support up to x-of-3 multisig txns as standard
 695                 if (n < 1 || n > 3)
 696                 {
 697                     return false;
 698                 }
 699                 if (m < 1 || m > n)
 700                 {
 701                     return false;
 702                 }
 703             }
 704
 705             return whichType != txnouttype.TX_NONSTANDARD;
 706         }
 707
 708         /// <summary>
 709         /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
 710         /// </summary>
 711         /// <param name="scriptPubKey">CScript instance</param>
 712         /// <param name="typeRet">Output type</param>
 713         /// <param name="solutions">Set of solutions</param>
 714         /// <returns>Result</returns>
 715         public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
 716         {
 717             solutions = new List<IEnumerable<byte>>();
 718
 719             // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types.
 720
 721             // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
 722             if (scriptPubKey.IsPayToScriptHash)
 723             {
 724                 typeRet = txnouttype.TX_SCRIPTHASH;
 725
 726                 // Take 20 bytes with offset of 2 bytes
 727                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(2).Take(20);
 728                 solutions.Add(hashBytes);
 729
 730                 return true;
 731             }
 732
 733             // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 734             if (scriptPubKey.IsPayToPubKeyHash)
 735             {
 736                 typeRet = txnouttype.TX_PUBKEYHASH;
 737
 738                 // Take 20 bytes with offset of 3 bytes
 739                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(3).Take(20);
 740                 solutions.Add(hashBytes);
 741
 742                 return true;
 743             }
 744
 745             List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();
 746
 747             // Sender provides pubkey, receiver adds signature
 748             // [ECDSA public key] OP_CHECKSIG
 749             templateTuples.Add(
 750                 new Tuple<txnouttype, IEnumerable<byte>>(
 751                     txnouttype.TX_PUBKEY,
 752                     new byte[] {
 753                         (byte)instruction.OP_PUBKEY,
 754                         (byte)instruction.OP_CHECKSIG
 755                     })
 756             );
 757
 758             // Sender provides N pubkeys, receivers provides M signatures
 759             // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
 760             // Where N and M are small integer opcodes (OP1 ... OP_16)
 761             templateTuples.Add(
 762                 new Tuple<txnouttype, IEnumerable<byte>>(
 763                     txnouttype.TX_MULTISIG,
 764                     new byte[] {
 765                         (byte)instruction.OP_SMALLINTEGER,
 766                         (byte)instruction.OP_PUBKEYS,
 767                         (byte)instruction.OP_SMALLINTEGER,
 768                         (byte)instruction.OP_CHECKMULTISIG
 769                     })
 770             );
 771
 772             // Data-carrying output
 773             // OP_RETURN [up to 80 bytes of data]
 774             templateTuples.Add(
 775                 new Tuple<txnouttype, IEnumerable<byte>>(
 776                     txnouttype.TX_NULL_DATA,
 777                     new byte[] {
 778                         (byte)instruction.OP_RETURN,
 779                         (byte)instruction.OP_SMALLDATA
 780                     })
 781             );
 782
 783             // Nonstandard tx output
 784             typeRet = txnouttype.TX_NONSTANDARD;
 785
 786             foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
 787             {
 788                 CScript script1 = scriptPubKey;
 789                 CScript script2 = new CScript(templateTuple.Item2);
 790
 791                 instruction opcode1, opcode2;
 792
 793                 // Compare
 794                 ByteQueue bq1 = script1.GetByteQUeue();
 795                 ByteQueue bq2 = script2.GetByteQUeue();
 796
 797                 IEnumerable<byte> args1, args2;
 798
 799                 byte last1 = script1.Bytes.Last();
 800                 byte last2 = script2.Bytes.Last();
 801
 802                 while (true)
 803                 {
 804                     if (bq1.GetCurrent() == last1 && bq2.GetCurrent() == last2)
 805                     {
 806                         // Found a match
 807                         typeRet = templateTuple.Item1;
 808                         if (typeRet == txnouttype.TX_MULTISIG)
 809                         {
 810                             // Additional checks for TX_MULTISIG:
 811                             byte m = solutions.First().First();
 812                             byte n = solutions.Last().First();
 813
 814                             if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
 815                             {
 816                                 return false;
 817                             }
 818                         }
 819                         return true;
 820                     }
 821
 822                     if (!GetOp(ref bq1, out opcode1, out args1))
 823                     {
 824                         break;
 825                     }
 826                     if (!GetOp(ref bq2, out opcode2, out args2))
 827                     {
 828                         break;
 829                     }
 830
 831                     // Template matching opcodes:
 832                     if (opcode2 == instruction.OP_PUBKEYS)
 833                     {
 834                         while (args1.Count() >= 33 && args1.Count() <= 120)
 835                         {
 836                             solutions.Add(args1);
 837                             if (!GetOp(ref bq1, out opcode1, out args1))
 838                             {
 839                                 break;
 840                             }
 841                         }
 842                         if (!GetOp(ref bq2, out opcode2, out args2))
 843                             break;
 844                         // Normal situation is to fall through
 845                         // to other if/else statements
 846                     }
 847                     if (opcode2 == instruction.OP_PUBKEY)
 848                     {
 849                         if (args1.Count() < 33 || args1.Count() > 120)
 850                         {
 851                             break;
 852                         }
 853                         solutions.Add(args1);
 854                     }
 855                     else if (opcode2 == instruction.OP_PUBKEYHASH)
 856                     {
 857                         if (args1.Count() != 20) // hash160 size
 858                         {
 859                             break;
 860                         }
 861                         solutions.Add(args1);
 862                     }
 863                     else if (opcode2 == instruction.OP_SMALLINTEGER)
 864                     {
 865                         // Single-byte small integer pushed onto solutions
 866                         if (opcode1 == instruction.OP_0 || (opcode1 >= instruction.OP_1 && opcode1 <= instruction.OP_16))
 867                         {
 868                             byte n = (byte)DecodeOP_N(opcode1);
 869                             solutions.Add(new byte[] { n });
 870                         }
 871                         else
 872                         {
 873                             break;
 874                         }
 875                     }
 876                     else if (opcode2 == instruction.OP_SMALLDATA)
 877                     {
 878                         // small pushdata, <= 80 bytes
 879                         if (args1.Count() > 80)
 880                         {
 881                             break;
 882                         }
 883                     }
 884                     else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
 885                     {
 886                         // Others must match exactly
 887                         break;
 888                     }
 889                 }
 890             }
 891
 892             solutions.Clear();
 893             typeRet = txnouttype.TX_NONSTANDARD;
 894
 895             return false;
 896         }
 897
 898         public static Hash256 SignatureHash(CScript scriptCode, CTransaction txTo, int nIn, int nHashType)
 899         {
 900             if (nIn >= txTo.vin.Length)
 901             {
 902                 StringBuilder sb = new StringBuilder();
 903                 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
 904                 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
 905             }
 906
 907             CTransaction txTmp = new CTransaction(txTo);
 908
 909             // In case concatenating two scripts ends up with two codeseparators,
 910             // or an extra one at the end, this prevents all those possible incompatibilities.
 911             scriptCode.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
 912
 913             // Blank out other inputs' signatures
 914             for (int i = 0; i < txTmp.vin.Length; i++)
 915             {
 916                 txTmp.vin[i].scriptSig = new CScript();
 917             }
 918             txTmp.vin[nIn].scriptSig = scriptCode;
 919
 920             // Blank out some of the outputs
 921             if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
 922             {
 923                 // Wildcard payee
 924                 txTmp.vout = new CTxOut[0];
 925
 926                 // Let the others update at will
 927                 for (int i = 0; i < txTmp.vin.Length; i++)
 928                 {
 929                     if (i != nIn)
 930                     {
 931                         txTmp.vin[i].nSequence = 0;
 932                     }
 933                 }
 934             }
 935             else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
 936             {
 937                 // Only lock-in the txout payee at same index as txin
 938                 int nOut = nIn;
 939                 if (nOut >= txTmp.vout.Length)
 940                 {
 941                     StringBuilder sb = new StringBuilder();
 942                     sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
 943                     throw new ArgumentOutOfRangeException("nOut", sb.ToString());
 944                 }
 945                 Array.Resize(ref txTmp.vout, nOut + 1);
 946
 947                 for (int i = 0; i < nOut; i++)
 948                 {
 949                     txTmp.vout[i] = new CTxOut();
 950                 }
 951
 952                 // Let the others update at will
 953                 for (int i = 0; i < txTmp.vin.Length; i++)
 954                 {
 955                     if (i != nIn)
 956                     {
 957                         txTmp.vin[i].nSequence = 0;
 958                     }
 959                 }
 960             }
 961
 962             // Blank out other inputs completely, not recommended for open transactions
 963             if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
 964             {
 965                 txTmp.vin[0] = txTmp.vin[nIn];
 966                 Array.Resize(ref txTmp.vin, 1);
 967             }
 968
 969             // Serialize and hash
 970             List<byte> b = new List<byte>();
 971             b.AddRange(txTmp.Bytes);
 972             b.AddRange(BitConverter.GetBytes(nHashType));
 973
 974             return Hash256.Compute256(b);
 975         }
 976
 977         public class StackMachineException : Exception
 978         {
 979             public StackMachineException()
 980             {
 981             }
 982
 983             public StackMachineException(string message)
 984                 : base(message)
 985             {
 986             }
 987
 988             public StackMachineException(string message, Exception inner)
 989                 : base(message, inner)
 990             {
 991             }
 992         }
 993
 994
 995         //
 996         // Script is a stack machine (like Forth) that evaluates a predicate
 997         // returning a bool indicating valid or not.  There are no loops.
 998         //
 999
1000         /// <summary>
1001         /// Remove last element from stack
1002         /// </summary>
1003         /// <param name="stack">Stack reference</param>
1004         static void popstack(ref List<IEnumerable<byte>> stack)
1005         {
1006             int nCount = stack.Count;
1007             if (nCount == 0)
1008                 throw new StackMachineException("popstack() : stack empty");
1009             stack.RemoveAt(nCount - 1);
1010         }
1011
1012         /// <summary>
1013         /// Get element at specified stack depth
1014         /// </summary>
1015         /// <param name="stack">Stack reference</param>
1016         /// <param name="nDepth">Depth</param>
1017         /// <returns>Byte sequence</returns>
1018         static IEnumerable<byte> stacktop(ref List<IEnumerable<byte>> stack, int nDepth)
1019         {
1020             int nStackElement = stack.Count + nDepth;
1021
1022             if (nDepth >= 0)
1023             {
1024                 StringBuilder sb = new StringBuilder();
1025                 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
1026
1027                 throw new StackMachineException(sb.ToString());
1028             }
1029
1030             if (nStackElement < 0)
1031             {
1032                 StringBuilder sb = new StringBuilder();
1033                 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
1034
1035                 throw new StackMachineException(sb.ToString());
1036             }
1037
1038             return stack[nStackElement];
1039         }
1040
1041         /// <summary>
1042         /// Cast argument to boolean value
1043         /// </summary>
1044         /// <param name="value">Some byte sequence</param>
1045         /// <returns></returns>
1046         private static bool CastToBool(IEnumerable<byte> arg)
1047         {
1048             byte[] value = arg.ToArray();
1049
1050             for (var i = 0; i < value.Length; i++)
1051             {
1052                 if (value[i] != 0)
1053                 {
1054                     // Can be negative zero
1055                     if (i == value.Length - 1 && value[i] == 0x80)
1056                     {
1057                         return false;
1058                     }
1059
1060                     return true;
1061                 }
1062             }
1063
1064             return false;
1065         }
1066
1067         /// <summary>
1068         /// Cast argument to integer value
1069         /// </summary>
1070         /// <param name="value"></param>
1071         /// <returns></returns>
1072         private static BigInteger CastToBigInteger(IEnumerable<byte> value)
1073         {
1074             if (value.Count() > 4)
1075             {
1076                 throw new StackMachineException("CastToBigInteger() : overflow");
1077             }
1078
1079             return new BigInteger(value.ToArray());
1080         }
1081
1082         static bool EvalScript(ref List<IEnumerable<byte>> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
1083         {
1084             instruction opcode;
1085
1086             ByteQueue CodeQueue = script.GetByteQUeue();
1087
1088             List<bool> vfExec = new List<bool>();
1089             List<IEnumerable<byte>> altStack = new List<IEnumerable<byte>>();
1090
1091             byte[] falseBytes = new byte[0];
1092             byte[] trueBytes = new byte[] { 0x01 };
1093
1094             if (script.Bytes.Count() > 10000)
1095             {
1096                 return false; // Size limit failed
1097             }
1098
1099             int nOpCount = 0;
1100             int nCodeHashBegin = 0;
1101
1102             IEnumerable<byte> pushArg;
1103
1104             while (GetOp(ref CodeQueue, out opcode, out pushArg)) // Read instructions
1105             {
1106                 bool fExec = vfExec.IndexOf(false) != -1;
1107
1108                 if (pushArg.Count() > 520)
1109                 {
1110                     return false; // Script element size limit failed
1111                 }
1112
1113                 if (opcode > instruction.OP_16 && ++nOpCount > 201)
1114                 {
1115                     return false;
1116                 }
1117
1118                 if (fExec && 0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
1119                 {
1120                     stack.Add(pushArg); // Push argument to stack
1121                 }
1122                 else if (fExec || (instruction.OP_IF <= opcode && opcode <= instruction.OP_ENDIF))
1123                     switch (opcode)
1124                     {
1125                         //
1126                         // Disabled opcodes
1127                         //
1128                         case instruction.OP_CAT:
1129                         case instruction.OP_SUBSTR:
1130                         case instruction.OP_LEFT:
1131                         case instruction.OP_RIGHT:
1132                         case instruction.OP_INVERT:
1133                         case instruction.OP_AND:
1134                         case instruction.OP_OR:
1135                         case instruction.OP_XOR:
1136                         case instruction.OP_2MUL:
1137                         case instruction.OP_2DIV:
1138                         case instruction.OP_MUL:
1139                         case instruction.OP_DIV:
1140                         case instruction.OP_MOD:
1141                         case instruction.OP_LSHIFT:
1142                         case instruction.OP_RSHIFT:
1143                             return false;
1144
1145                         //
1146                         // Push integer instructions
1147                         //
1148                         case instruction.OP_1NEGATE:
1149                         case instruction.OP_1:
1150                         case instruction.OP_2:
1151                         case instruction.OP_3:
1152                         case instruction.OP_4:
1153                         case instruction.OP_5:
1154                         case instruction.OP_6:
1155                         case instruction.OP_7:
1156                         case instruction.OP_8:
1157                         case instruction.OP_9:
1158                         case instruction.OP_10:
1159                         case instruction.OP_11:
1160                         case instruction.OP_12:
1161                         case instruction.OP_13:
1162                         case instruction.OP_14:
1163                         case instruction.OP_15:
1164                         case instruction.OP_16:
1165                             {
1166                                 // ( -- value)
1167                                 BigInteger bn = DecodeOP_N(opcode);
1168                                 stack.Add(bn.ToByteArray());
1169                             }
1170                             break;
1171
1172                         //
1173                         // Extension
1174                         //
1175                         case instruction.OP_NOP:
1176                         case instruction.OP_NOP1:
1177                         case instruction.OP_NOP2:
1178                         case instruction.OP_NOP3:
1179                         case instruction.OP_NOP4:
1180                         case instruction.OP_NOP5:
1181                         case instruction.OP_NOP6:
1182                         case instruction.OP_NOP7:
1183                         case instruction.OP_NOP8:
1184                         case instruction.OP_NOP9:
1185                         case instruction.OP_NOP10:
1186                             {
1187                                 // Just do nothing
1188                                 break;
1189                             }
1190
1191                         //
1192                         // Control
1193                         //
1194                         case instruction.OP_IF:
1195                         case instruction.OP_NOTIF:
1196                             {
1197                                 // <expression> if [statements] [else [statements]] endif
1198                                 bool fValue = false;
1199                                 if (fExec)
1200                                 {
1201                                     if (stack.Count() < 1)
1202                                     {
1203                                         return false;
1204                                     }
1205                                     IEnumerable<byte> vch = stacktop(ref stack, -1);
1206                                     fValue = CastToBool(vch);
1207                                     if (opcode == instruction.OP_NOTIF)
1208                                     {
1209                                         fValue = !fValue;
1210                                     }
1211                                     popstack(ref stack);
1212                                 }
1213                                 vfExec.Add(fValue);
1214                             }
1215                             break;
1216
1217                         case instruction.OP_ELSE:
1218                             {
1219                                 int nExecCount = vfExec.Count();
1220                                 if (nExecCount == 0)
1221                                 {
1222                                     return false;
1223                                 }
1224                                 vfExec[nExecCount - 1] = !vfExec[nExecCount - 1];
1225                             }
1226                             break;
1227
1228                         case instruction.OP_ENDIF:
1229                             {
1230                                 int nExecCount = vfExec.Count();
1231                                 if (nExecCount == 0)
1232                                 {
1233                                     return false;
1234                                 }
1235                                 vfExec.RemoveAt(nExecCount - 1);
1236                             }
1237                             break;
1238
1239                         case instruction.OP_VERIFY:
1240                             {
1241                                 // (true -- ) or
1242                                 // (false -- false) and return
1243                                 if (stack.Count() < 1)
1244                                 {
1245                                     return false;
1246                                 }
1247
1248                                 bool fValue = CastToBool(stacktop(ref stack, -1));
1249                                 if (fValue)
1250                                 {
1251                                     popstack(ref stack);
1252                                 }
1253                                 else
1254                                 {
1255                                     return false;
1256                                 }
1257                             }
1258                             break;
1259
1260                         case instruction.OP_RETURN:
1261                             {
1262                                 return false;
1263                             }
1264
1265                         //
1266                         // Stack ops
1267                         //
1268                         case instruction.OP_TOALTSTACK:
1269                             {
1270                                 if (stack.Count() < 1)
1271                                 {
1272                                     return false;
1273                                 }
1274                                 altStack.Add(stacktop(ref stack, -1));
1275                                 popstack(ref stack);
1276                             }
1277                             break;
1278
1279                         case instruction.OP_FROMALTSTACK:
1280                             {
1281                                 if (altStack.Count() < 1)
1282                                 {
1283                                     return false;
1284                                 }
1285                                 stack.Add(stacktop(ref stack, -1));
1286                                 popstack(ref altStack);
1287                             }
1288                             break;
1289
1290                         case instruction.OP_2DROP:
1291                             {
1292                                 // (x1 x2 -- )
1293                                 if (stack.Count() < 2)
1294                                 {
1295                                     return false;
1296                                 }
1297                                 popstack(ref stack);
1298                                 popstack(ref stack);
1299                             }
1300                             break;
1301
1302                         case instruction.OP_2DUP:
1303                             {
1304                                 // (x1 x2 -- x1 x2 x1 x2)
1305                                 if (stack.Count() < 2)
1306                                 {
1307                                     return false;
1308                                 }
1309                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1310                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1311                                 stack.Add(vch1);
1312                                 stack.Add(vch2);
1313                             }
1314                             break;
1315
1316                         case instruction.OP_3DUP:
1317                             {
1318                                 // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
1319                                 if (stack.Count() < 3)
1320                                 {
1321                                     return false;
1322                                 }
1323                                 IEnumerable<byte> vch1 = stacktop(ref stack, -3);
1324                                 IEnumerable<byte> vch2 = stacktop(ref stack, -2);
1325                                 IEnumerable<byte> vch3 = stacktop(ref stack, -1);
1326                                 stack.Add(vch1);
1327                                 stack.Add(vch2);
1328                                 stack.Add(vch3);
1329                             }
1330                             break;
1331
1332                         case instruction.OP_2OVER:
1333                             {
1334                                 // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
1335                                 if (stack.Count() < 4)
1336                                 {
1337                                     return false;
1338                                 }
1339                                 IEnumerable<byte> vch1 = stacktop(ref stack, -4);
1340                                 IEnumerable<byte> vch2 = stacktop(ref stack, -3);
1341                                 stack.Add(vch1);
1342                                 stack.Add(vch2);
1343                             }
1344                             break;
1345
1346                         case instruction.OP_2ROT:
1347                             {
1348                                 int nStackDepth = stack.Count();
1349                                 // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
1350                                 if (nStackDepth < 6)
1351                                 {
1352                                     return false;
1353                                 }
1354                                 IEnumerable<byte> vch1 = stacktop(ref stack, -6);
1355                                 IEnumerable<byte> vch2 = stacktop(ref stack, -5);
1356                                 stack.RemoveRange(nStackDepth - 6, 2);
1357                                 stack.Add(vch1);
1358                                 stack.Add(vch2);
1359                             }
1360                             break;
1361
1362                         case instruction.OP_2SWAP:
1363                             {
1364                                 // (x1 x2 x3 x4 -- x3 x4 x1 x2)
1365                                 int nStackDepth = stack.Count();
1366                                 if (nStackDepth < 4)
1367                                 {
1368                                     return false;
1369                                 }
1370                                 stack.Swap(nStackDepth - 4, nStackDepth - 2);
1371                                 stack.Swap(nStackDepth - 3, nStackDepth - 1);
1372                             }
1373                             break;
1374
1375                         case instruction.OP_IFDUP:
1376                             {
1377                                 // (x - 0 | x x)
1378                                 if (stack.Count() < 1)
1379                                 {
1380                                     return false;
1381                                 }
1382
1383                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1384
1385                                 if (CastToBool(vch))
1386                                 {
1387                                     stack.Add(vch);
1388                                 }
1389                             }
1390                             break;
1391
1392                         case instruction.OP_DEPTH:
1393                             {
1394                                 // -- stacksize
1395                                 BigInteger bn = new BigInteger((ushort)stack.Count());
1396                                 stack.Add(bn.ToByteArray());
1397                             }
1398                             break;
1399
1400                         case instruction.OP_DROP:
1401                             {
1402                                 // (x -- )
1403                                 if (stack.Count() < 1)
1404                                 {
1405                                     return false;
1406                                 }
1407
1408                                 popstack(ref stack);
1409                             }
1410                             break;
1411
1412                         case instruction.OP_DUP:
1413                             {
1414                                 // (x -- x x)
1415                                 if (stack.Count() < 1)
1416                                 {
1417                                     return false;
1418                                 }
1419
1420                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1421                                 stack.Add(vch);
1422                             }
1423                             break;
1424
1425                         case instruction.OP_NIP:
1426                             {
1427                                 // (x1 x2 -- x2)
1428                                 int nStackDepth = stack.Count();
1429                                 if (nStackDepth < 2)
1430                                 {
1431                                     return false;
1432                                 }
1433
1434                                 stack.RemoveAt(nStackDepth - 2);
1435                             }
1436                             break;
1437
1438                         case instruction.OP_OVER:
1439                             {
1440                                 // (x1 x2 -- x1 x2 x1)
1441                                 if (stack.Count() < 2)
1442                                 {
1443                                     return false;
1444                                 }
1445
1446                                 IEnumerable<byte> vch = stacktop(ref stack, -2);
1447                                 stack.Add(vch);
1448                             }
1449                             break;
1450
1451                         case instruction.OP_PICK:
1452                         case instruction.OP_ROLL:
1453                             {
1454                                 // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
1455                                 // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
1456
1457                                 int nStackDepth = stack.Count();
1458                                 if (nStackDepth < 2)
1459                                 {
1460                                     return false;
1461                                 }
1462
1463                                 int n = (int)CastToBigInteger(stacktop(ref stack, -1));
1464                                 popstack(ref stack);
1465
1466                                 if (n < 0 || n >= stack.Count())
1467                                 {
1468                                     return false;
1469                                 }
1470
1471                                 IEnumerable<byte> vch = stacktop(ref stack, -n - 1);
1472                                 if (opcode == instruction.OP_ROLL)
1473                                 {
1474                                     stack.RemoveAt(nStackDepth - n - 1);
1475                                 }
1476
1477                                 stack.Add(vch);
1478                             }
1479                             break;
1480
1481                         case instruction.OP_ROT:
1482                             {
1483                                 // (x1 x2 x3 -- x2 x3 x1)
1484                                 //  x2 x1 x3  after first swap
1485                                 //  x2 x3 x1  after second swap
1486                                 int nStackDepth = stack.Count();
1487                                 if (nStackDepth < 3)
1488                                 {
1489                                     return false;
1490                                 }
1491                                 stack.Swap(nStackDepth - 3, nStackDepth - 2);
1492                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1493
1494                             }
1495                             break;
1496
1497                         case instruction.OP_SWAP:
1498                             {
1499                                 // (x1 x2 -- x2 x1)
1500                                 int nStackDepth = stack.Count();
1501                                 if (nStackDepth < 2)
1502                                 {
1503                                     return false;
1504                                 }
1505                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1506                             }
1507                             break;
1508
1509                         case instruction.OP_TUCK:
1510                             {
1511                                 // (x1 x2 -- x2 x1 x2)
1512                                 int nStackDepth = stack.Count();
1513                                 if (nStackDepth < 2)
1514                                 {
1515                                     return false;
1516                                 }
1517                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1518                                 stack.Insert(nStackDepth - 2, vch);
1519                             }
1520                             break;
1521
1522
1523                         case instruction.OP_SIZE:
1524                             {
1525                                 // (in -- in size)
1526                                 if (stack.Count() < 1)
1527                                 {
1528                                     return false;
1529                                 }
1530
1531                                 BigInteger bnSize = new BigInteger((ushort)stacktop(ref stack, -1).Count());
1532                                 stack.Add(bnSize.ToByteArray());
1533                             }
1534                             break;
1535
1536
1537                         //
1538                         // Bitwise logic
1539                         //
1540                         case instruction.OP_EQUAL:
1541                         case instruction.OP_EQUALVERIFY:
1542                             //case instruction.OP_NOTEQUAL: // use OP_NUMNOTEQUAL
1543                             {
1544                                 // (x1 x2 - bool)
1545                                 if (stack.Count() < 2)
1546                                 {
1547                                     return false;
1548                                 }
1549
1550                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1551                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1552                                 bool fEqual = (vch1 == vch2);
1553                                 // OP_NOTEQUAL is disabled because it would be too easy to say
1554                                 // something like n != 1 and have some wiseguy pass in 1 with extra
1555                                 // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
1556                                 //if (opcode == instruction.OP_NOTEQUAL)
1557                                 //    fEqual = !fEqual;
1558                                 popstack(ref stack);
1559                                 popstack(ref stack);
1560                                 stack.Add(fEqual ? trueBytes : falseBytes);
1561
1562                                 if (opcode == instruction.OP_EQUALVERIFY)
1563                                 {
1564                                     if (fEqual)
1565                                     {
1566                                         popstack(ref stack);
1567                                     }
1568                                     else
1569                                     {
1570                                         return false;
1571                                     }
1572                                 }
1573                             }
1574                             break;
1575
1576
1577                         //
1578                         // Numeric
1579                         //
1580                         case instruction.OP_1ADD:
1581                         case instruction.OP_1SUB:
1582                         case instruction.OP_NEGATE:
1583                         case instruction.OP_ABS:
1584                         case instruction.OP_NOT:
1585                         case instruction.OP_0NOTEQUAL:
1586                             {
1587                                 // (in -- out)
1588                                 if (stack.Count() < 1)
1589                                 {
1590                                     return false;
1591                                 }
1592
1593                                 BigInteger bn = CastToBigInteger(stacktop(ref stack, -1));
1594                                 switch (opcode)
1595                                 {
1596                                     case instruction.OP_1ADD:
1597                                         bn = bn + 1;
1598                                         break;
1599                                     case instruction.OP_1SUB:
1600                                         bn = bn - 1;
1601                                         break;
1602                                     case instruction.OP_NEGATE:
1603                                         bn = -bn;
1604                                         break;
1605                                     case instruction.OP_ABS:
1606                                         bn = BigInteger.Abs(bn);
1607                                         break;
1608                                     case instruction.OP_NOT:
1609                                         bn = bn == 0 ? 1 : 0;
1610                                         break;
1611                                     case instruction.OP_0NOTEQUAL:
1612                                         bn = bn != 0 ? 1 : 0;
1613                                         break;
1614
1615                                     default:
1616                                         throw new StackMachineException("invalid instruction");
1617                                 }
1618
1619                                 popstack(ref stack);
1620                                 stack.Add(bn.ToByteArray());
1621                             }
1622                             break;
1623
1624                         case instruction.OP_ADD:
1625                         case instruction.OP_SUB:
1626                         case instruction.OP_BOOLAND:
1627                         case instruction.OP_BOOLOR:
1628                         case instruction.OP_NUMEQUAL:
1629                         case instruction.OP_NUMEQUALVERIFY:
1630                         case instruction.OP_NUMNOTEQUAL:
1631                         case instruction.OP_LESSTHAN:
1632                         case instruction.OP_GREATERTHAN:
1633                         case instruction.OP_LESSTHANOREQUAL:
1634                         case instruction.OP_GREATERTHANOREQUAL:
1635                         case instruction.OP_MIN:
1636                         case instruction.OP_MAX:
1637                             {
1638                                 // (x1 x2 -- out)
1639                                 if (stack.Count() < 2)
1640                                 {
1641                                     return false;
1642                                 }
1643
1644                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -2));
1645                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -1));
1646                                 BigInteger bn = 0;
1647
1648                                 switch (opcode)
1649                                 {
1650                                     case instruction.OP_ADD:
1651                                         bn = bn1 + bn2;
1652                                         break;
1653                                     case instruction.OP_SUB:
1654                                         bn = bn1 - bn2;
1655                                         break;
1656                                     case instruction.OP_BOOLAND:
1657                                         bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1658                                         break;
1659                                     case instruction.OP_BOOLOR:
1660                                         bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1661                                         break;
1662                                     case instruction.OP_NUMEQUAL:
1663                                         bn = (bn1 == bn2) ? 1 : 0;
1664                                         break;
1665                                     case instruction.OP_NUMEQUALVERIFY:
1666                                         bn = (bn1 == bn2) ? 1 : 0;
1667                                         break;
1668                                     case instruction.OP_NUMNOTEQUAL:
1669                                         bn = (bn1 != bn2) ? 1 : 0;
1670                                         break;
1671                                     case instruction.OP_LESSTHAN:
1672                                         bn = (bn1 < bn2) ? 1 : 0;
1673                                         break;
1674                                     case instruction.OP_GREATERTHAN:
1675                                         bn = (bn1 > bn2) ? 1 : 0;
1676                                         break;
1677                                     case instruction.OP_LESSTHANOREQUAL:
1678                                         bn = (bn1 <= bn2) ? 1 : 0;
1679                                         break;
1680                                     case instruction.OP_GREATERTHANOREQUAL:
1681                                         bn = (bn1 >= bn2) ? 1 : 0;
1682                                         break;
1683                                     case instruction.OP_MIN:
1684                                         bn = (bn1 < bn2 ? bn1 : bn2);
1685                                         break;
1686                                     case instruction.OP_MAX:
1687                                         bn = (bn1 > bn2 ? bn1 : bn2);
1688                                         break;
1689
1690                                     default:
1691                                         throw new StackMachineException("invalid instruction");
1692                                 }
1693
1694                                 popstack(ref stack);
1695                                 popstack(ref stack);
1696                                 stack.Add(bn.ToByteArray());
1697
1698                                 if (opcode == instruction.OP_NUMEQUALVERIFY)
1699                                 {
1700                                     if (CastToBool(stacktop(ref stack, -1)))
1701                                     {
1702                                         popstack(ref stack);
1703                                     }
1704                                     else
1705                                     {
1706                                         return false;
1707                                     }
1708                                 }
1709                             }
1710                             break;
1711
1712                         case instruction.OP_WITHIN:
1713                             {
1714                                 // (x min max -- out)
1715                                 if (stack.Count() < 3)
1716                                     return false;
1717                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -3));
1718                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -2));
1719                                 BigInteger bn3 = CastToBigInteger(stacktop(ref stack, -1));
1720                                 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1721                                 popstack(ref stack);
1722                                 popstack(ref stack);
1723                                 popstack(ref stack);
1724                                 stack.Add(fValue ? trueBytes : falseBytes);
1725                             }
1726                             break;
1727
1728
1729                         //
1730                         // Crypto
1731                         //
1732                         case instruction.OP_RIPEMD160:
1733                         case instruction.OP_SHA1:
1734                         case instruction.OP_SHA256:
1735                         case instruction.OP_HASH160:
1736                         case instruction.OP_HASH256:
1737                             {
1738                                 // (in -- hash)
1739                                 if (stack.Count() < 1)
1740                                     return false;
1741                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1742                                 IEnumerable<byte> vchHash = null;
1743                                 if (opcode == instruction.OP_RIPEMD160)
1744                                 {
1745                                     RIPEMD160 hash = RIPEMD160.Compute160(vch);
1746                                     vchHash = hash.hashBytes;
1747                                 }
1748                                 else if (opcode == instruction.OP_SHA1)
1749                                 {
1750                                     SHA1 hash = SHA1.Compute1(vch);
1751                                     vchHash = hash.hashBytes;
1752                                 }
1753                                 else if (opcode == instruction.OP_SHA256)
1754                                 {
1755                                     SHA256 hash = SHA256.Compute256(vch);
1756                                     vchHash = hash.hashBytes;
1757                                 }
1758                                 else if (opcode == instruction.OP_HASH160)
1759                                 {
1760                                     Hash160 hash = Hash160.Compute160(vch);
1761                                     vchHash = hash.hashBytes;
1762                                 }
1763                                 else if (opcode == instruction.OP_HASH256)
1764                                 {
1765                                     Hash256 hash = Hash256.Compute256(vch);
1766                                     vchHash = hash.hashBytes;
1767                                 }
1768                                 popstack(ref stack);
1769                                 stack.Add(vchHash);
1770                             }
1771                             break;
1772
1773                         case instruction.OP_CODESEPARATOR:
1774                             {
1775                                 // Hash starts after the code separator
1776                                 nCodeHashBegin = CodeQueue.CurrentIndex;
1777                             }
1778                             break;
1779
1780                         case instruction.OP_CHECKSIG:
1781                         case instruction.OP_CHECKSIGVERIFY:
1782                             {
1783                                 // (sig pubkey -- bool)
1784                                 if (stack.Count() < 2)
1785                                 {
1786                                     return false;
1787                                 }
1788
1789                                 IList<byte> sigBytes = stacktop(ref stack, -2).ToList();
1790                                 IList<byte> pubkeyBytes = stacktop(ref stack, -1).ToList();
1791
1792                                 // Subset of script starting at the most recent codeseparator
1793                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1794
1795                                 // There's no way for a signature to sign itself
1796                                 scriptCode.RemovePattern(sigBytes);
1797
1798                                 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes.ToList(), flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1799
1800                                 popstack(ref stack);
1801                                 popstack(ref stack);
1802                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1803                                 if (opcode == instruction.OP_CHECKSIGVERIFY)
1804                                 {
1805                                     if (fSuccess)
1806                                     {
1807                                         popstack(ref stack);
1808                                     }
1809                                     else
1810                                     {
1811                                         return false;
1812                                     }
1813                                 }
1814                             }
1815                             break;
1816
1817                         case instruction.OP_CHECKMULTISIG:
1818                         case instruction.OP_CHECKMULTISIGVERIFY:
1819                             {
1820                                 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1821
1822                                 int i = 1;
1823                                 if (stack.Count() < i)
1824                                 {
1825                                     return false;
1826                                 }
1827
1828                                 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1829                                 if (nKeysCount < 0 || nKeysCount > 20)
1830                                 {
1831                                     return false;
1832                                 }
1833                                 nOpCount += nKeysCount;
1834                                 if (nOpCount > 201)
1835                                 {
1836                                     return false;
1837                                 }
1838                                 int ikey = ++i;
1839                                 i += nKeysCount;
1840                                 if (stack.Count() < i)
1841                                 {
1842                                     return false;
1843                                 }
1844
1845                                 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1846                                 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1847                                 {
1848                                     return false;
1849                                 }
1850                                 int isig = ++i;
1851                                 i += nSigsCount;
1852                                 if (stack.Count() < i)
1853                                 {
1854                                     return false;
1855                                 }
1856
1857                                 // Subset of script starting at the most recent codeseparator
1858                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1859
1860                                 // There is no way for a signature to sign itself, so we need to drop the signatures
1861                                 for (int k = 0; k < nSigsCount; k++)
1862                                 {
1863                                     IEnumerable<byte> vchSig = stacktop(ref stack, -isig - k);
1864                                     scriptCode.RemovePattern(vchSig.ToList());
1865                                 }
1866
1867                                 bool fSuccess = true;
1868                                 while (fSuccess && nSigsCount > 0)
1869                                 {
1870                                     IList<byte> sigBytes = stacktop(ref stack, -isig).ToList();
1871                                     IList<byte> pubKeyBytes = stacktop(ref stack, -ikey).ToList();
1872
1873                                     // Check signature
1874                                     bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes.ToList(), flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1875
1876                                     if (fOk)
1877                                     {
1878                                         isig++;
1879                                         nSigsCount--;
1880                                     }
1881                                     ikey++;
1882                                     nKeysCount--;
1883
1884                                     // If there are more signatures left than keys left,
1885                                     // then too many signatures have failed
1886                                     if (nSigsCount > nKeysCount)
1887                                     {
1888                                         fSuccess = false;
1889                                     }
1890                                 }
1891
1892                                 while (i-- > 1)
1893                                 {
1894                                     popstack(ref stack);
1895                                 }
1896
1897                                 // A bug causes CHECKMULTISIG to consume one extra argument
1898                                 // whose contents were not checked in any way.
1899                                 //
1900                                 // Unfortunately this is a potential source of mutability,
1901                                 // so optionally verify it is exactly equal to zero prior
1902                                 // to removing it from the stack.
1903                                 if (stack.Count() < 1)
1904                                 {
1905                                     return false;
1906                                 }
1907                                 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1908                                 {
1909                                     return false; // CHECKMULTISIG dummy argument not null
1910                                 }
1911                                 popstack(ref stack);
1912
1913                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1914
1915                                 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1916                                 {
1917                                     if (fSuccess)
1918                                     {
1919                                         popstack(ref stack);
1920                                     }
1921                                     else
1922                                     {
1923                                         return false;
1924                                     }
1925                                 }
1926                             }
1927                             break;
1928
1929                         default:
1930                             return false;
1931                     }
1932
1933                 // Size limits
1934                 if (stack.Count() + altStack.Count() > 1000)
1935                 {
1936                     return false;
1937                 }
1938             }
1939
1940
1941             if (vfExec.Count() == 0)
1942             {
1943                 return false;
1944             }
1945
1946             return true;
1947         }
1948
1949
1950         static bool IsCanonicalPubKey(IList<byte> pubKeyBytes, int flags)
1951         {
1952             if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1953                 return true;
1954
1955             if (pubKeyBytes.Count() < 33)
1956                 return false;  // Non-canonical public key: too short
1957             if (pubKeyBytes[0] == 0x04)
1958             {
1959                 if (pubKeyBytes.Count() != 65)
1960                     return false; // Non-canonical public key: invalid length for uncompressed key
1961             }
1962             else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1963             {
1964                 if (pubKeyBytes.Count() != 33)
1965                     return false; // Non-canonical public key: invalid length for compressed key
1966             }
1967             else
1968             {
1969                 return false; // Non-canonical public key: compressed nor uncompressed
1970             }
1971             return true;
1972         }
1973
1974         static bool IsCanonicalSignature(IList<byte> sigBytes, int flags)
1975         {
1976             // STUB
1977
1978             return true;
1979         }
1980
1981         static bool CheckSig(IList<byte> vchSig, IList<byte> vchPubKey, CScript scriptCode, CTransaction txTo, int nIn, int nHashType, int flags)
1982         {
1983             CPubKey pubkey;
1984
1985             try
1986             {
1987                 // Trying to initialize the public key instance
1988
1989                 pubkey = new CPubKey(vchPubKey);
1990             }
1991             catch (Exception)
1992             {
1993                 // Exception occurred while initializing the public key
1994
1995                 return false;
1996             }
1997
1998             if (!pubkey.IsValid)
1999             {
2000                 return false;
2001             }
2002
2003             if (vchSig.Count == 0)
2004             {
2005                 return false;
2006             }
2007
2008             // Hash type is one byte tacked on to the end of the signature
2009             if (nHashType == 0)
2010             {
2011                 nHashType = vchSig.Last();
2012             }
2013             else if (nHashType != vchSig.Last())
2014             {
2015                 return false;
2016             }
2017
2018             // Remove hash type
2019             vchSig.RemoveAt(vchSig.Count - 1);
2020
2021             Hash256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
2022
2023             if (!pubkey.VerifySignature(sighash, vchSig))
2024             {
2025                 return false;
2026             }
2027
2028             return true;
2029         }
2030     };
2031 }