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_SMALLINTEGER:
 461                     return "OP_SMALLINTEGER";
 462                 case instruction.OP_PUBKEYHASH:
 463                     return "OP_PUBKEYHASH";
 464                 case instruction.OP_PUBKEY:
 465                     return "OP_PUBKEY";
 466                 case instruction.OP_PUBKEYS:
 467                     return "OP_PUBKEYS";
 468                 case instruction.OP_SMALLDATA:
 469                     return "OP_SMALLDATA";
 470
 471                 case instruction.OP_INVALIDOPCODE:
 472                     return "OP_INVALIDOPCODE";
 473                 default:
 474                     return "OP_UNKNOWN";
 475             }
 476         }
 477
 478         /// <summary>
 479         /// Get next opcode from passed list of bytes and extract push arguments if there are some.
 480         /// </summary>
 481         /// <param name="codeBytes">ByteQueue reference.</param>
 482         /// <param name="opcodeRet">Found opcode.</param>
 483         /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
 484         /// <returns>Result of operation</returns>
 485         public static bool GetOp(ref ByteQueue codeBytes, out instruction opcodeRet, out IEnumerable<byte> bytesRet)
 486         {
 487             bytesRet = new List<byte>();
 488             opcodeRet = instruction.OP_INVALIDOPCODE;
 489
 490             instruction opcode;
 491
 492             try
 493             {
 494                 // Read instruction
 495                 opcode = (instruction)codeBytes.Get();
 496             }
 497             catch (ByteQueueException)
 498             {
 499                 // No instruction found there
 500                 return false;
 501             }
 502
 503             // Immediate operand
 504             if (opcode <= instruction.OP_PUSHDATA4)
 505             {
 506                 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
 507
 508                 try
 509                 {
 510                     if (opcode < instruction.OP_PUSHDATA1)
 511                     {
 512                         // Zero value opcodes (OP_0, OP_FALSE)
 513                         szBytes[3] = (byte)opcode;
 514                     }
 515                     else if (opcode == instruction.OP_PUSHDATA1)
 516                     {
 517                         // The next byte contains the number of bytes to be pushed onto the stack,
 518                         //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
 519                         szBytes[3] = (byte)codeBytes.Get();
 520                     }
 521                     else if (opcode == instruction.OP_PUSHDATA2)
 522                     {
 523                         // The next two bytes contain the number of bytes to be pushed onto the stack,
 524                         //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
 525                         codeBytes.Get(2).CopyTo(szBytes, 2);
 526                     }
 527                     else if (opcode == instruction.OP_PUSHDATA4)
 528                     {
 529                         // The next four bytes contain the number of bytes to be pushed onto the stack,
 530                         //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
 531                         szBytes = codeBytes.Get(4);
 532                     }
 533                 }
 534                 catch (ByteQueueException)
 535                 {
 536                     // Unable to read operand length
 537                     return false;
 538                 }
 539
 540                 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
 541
 542                 if (nSize > 0)
 543                 {
 544                     // If nSize is greater than zero then there is some data available
 545                     try
 546                     {
 547                         // Read found number of bytes into list of OP_PUSHDATAn arguments.
 548                         bytesRet = codeBytes.GetEnumerable(nSize);
 549                     }
 550                     catch (ByteQueueException)
 551                     {
 552                         // Unable to read data
 553                         return false;
 554                     }
 555                 }
 556             }
 557
 558             opcodeRet = opcode;
 559
 560             return true;
 561         }
 562
 563         /// <summary>
 564         /// Convert value bytes into readable representation.
 565         ///
 566         /// 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.
 567         /// </summary>
 568         /// <param name="bytes">Collection of value bytes.</param>
 569         /// <returns>Formatted value.</returns>
 570         public static string ValueString(IEnumerable<byte> bytes)
 571         {
 572             StringBuilder sb = new StringBuilder();
 573
 574             if (bytes.Count() <= 4)
 575             {
 576                 byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
 577                 bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());
 578
 579                 sb.Append(Interop.BEBytesToUInt32(valueBytes));
 580             }
 581             else
 582             {
 583                 return Interop.ToHex(bytes);
 584             }
 585
 586             return sb.ToString();
 587         }
 588
 589         /// <summary>
 590         /// Convert list of stack items into human readable representation.
 591         /// </summary>
 592         /// <param name="stackList">List of stack items.</param>
 593         /// <returns>Formatted value.</returns>
 594         public static string StackString(IList<IList<byte>> stackList)
 595         {
 596             StringBuilder sb = new StringBuilder();
 597             foreach (IList<byte> bytesList in stackList)
 598             {
 599                 sb.Append(ValueString(bytesList));
 600             }
 601
 602             return sb.ToString();
 603         }
 604
 605         /// <summary>
 606         /// Decode instruction to integer value
 607         /// </summary>
 608         /// <param name="opcode">Small integer opcode (OP_1_NEGATE and OP_0 - OP_16)</param>
 609         /// <returns>Small integer</returns>
 610         public static int DecodeOP_N(instruction opcode, bool AllowNegate = false)
 611         {
 612             if (AllowNegate && opcode == instruction.OP_1NEGATE)
 613             {
 614                 return -1;
 615             }
 616
 617             if (opcode == instruction.OP_0)
 618             {
 619                 return 0;
 620             }
 621
 622             // Only OP_n opcodes are supported, throw exception otherwise.
 623             if (opcode < instruction.OP_1 || opcode > instruction.OP_16)
 624             {
 625                 throw new ArgumentException("Invalid integer instruction.");
 626             }
 627
 628             return (int)opcode - (int)(instruction.OP_1 - 1);
 629         }
 630
 631         /// <summary>
 632         /// Converts integer into instruction
 633         /// </summary>
 634         /// <param name="n">Small integer from the range of -1 up to 16.</param>
 635         /// <returns>Corresponding opcode.</returns>
 636         public static instruction EncodeOP_N(int n, bool allowNegate = false)
 637         {
 638             if (allowNegate && n == -1)
 639             {
 640                 return instruction.OP_1NEGATE;
 641             }
 642
 643             if (n == 0)
 644             {
 645                 return instruction.OP_0;
 646             }
 647
 648             // The n value must be in the range of 0 to 16.
 649             if (n < 0 || n > 16)
 650                 throw new ArgumentException("Invalid integer value.");
 651             return (instruction.OP_1 + n - 1);
 652         }
 653
 654         public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
 655         {
 656             switch (t)
 657             {
 658                 case txnouttype.TX_NONSTANDARD:
 659                     return -1;
 660                 case txnouttype.TX_NULL_DATA:
 661                     return 1;
 662                 case txnouttype.TX_PUBKEY:
 663                     return 1;
 664                 case txnouttype.TX_PUBKEYHASH:
 665                     return 2;
 666                 case txnouttype.TX_MULTISIG:
 667                     if (solutions.Count() < 1 || solutions.First().Count() < 1)
 668                         return -1;
 669                     return solutions.First().First() + 1;
 670                 case txnouttype.TX_SCRIPTHASH:
 671                     return 1; // doesn't include args needed by the script
 672             }
 673             return -1;
 674         }
 675
 676         /// <summary>
 677         /// Is it a standart type of scriptPubKey?
 678         /// </summary>
 679         /// <param name="scriptPubKey">CScript instance</param>
 680         /// <param name="whichType">utut type</param>
 681         /// <returns>Checking result</returns>
 682         public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
 683         {
 684             IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();
 685
 686             if (!Solver(scriptPubKey, out whichType, out solutions))
 687             {
 688                 // No solutions found
 689                 return false;
 690             }
 691
 692             if (whichType == txnouttype.TX_MULTISIG)
 693             {
 694                 // Additional verification of OP_CHECKMULTISIG arguments
 695                 byte m = solutions.First().First();
 696                 byte n = solutions.Last().First();
 697
 698                 // Support up to x-of-3 multisig txns as standard
 699                 if (n < 1 || n > 3)
 700                 {
 701                     return false;
 702                 }
 703                 if (m < 1 || m > n)
 704                 {
 705                     return false;
 706                 }
 707             }
 708
 709             return whichType != txnouttype.TX_NONSTANDARD;
 710         }
 711
 712         /// <summary>
 713         /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
 714         /// </summary>
 715         /// <param name="scriptPubKey">CScript instance</param>
 716         /// <param name="typeRet">Output type</param>
 717         /// <param name="solutions">Set of solutions</param>
 718         /// <returns>Result</returns>
 719         public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
 720         {
 721             solutions = new List<IEnumerable<byte>>();
 722
 723             // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types.
 724
 725             // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
 726             if (scriptPubKey.IsPayToScriptHash)
 727             {
 728                 typeRet = txnouttype.TX_SCRIPTHASH;
 729
 730                 // Take 20 bytes with offset of 2 bytes
 731                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(2).Take(20);
 732                 solutions.Add(hashBytes);
 733
 734                 return true;
 735             }
 736
 737             // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 738             if (scriptPubKey.IsPayToPubKeyHash)
 739             {
 740                 typeRet = txnouttype.TX_PUBKEYHASH;
 741
 742                 // Take 20 bytes with offset of 3 bytes
 743                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(3).Take(20);
 744                 solutions.Add(hashBytes);
 745
 746                 return true;
 747             }
 748
 749             List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();
 750
 751             // Sender provides pubkey, receiver adds signature
 752             // [ECDSA public key] OP_CHECKSIG
 753             templateTuples.Add(
 754                 new Tuple<txnouttype, IEnumerable<byte>>(
 755                     txnouttype.TX_PUBKEY,
 756                     new byte[] {
 757                         (byte)instruction.OP_PUBKEY,
 758                         (byte)instruction.OP_CHECKSIG
 759                     })
 760             );
 761
 762             // Sender provides N pubkeys, receivers provides M signatures
 763             // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
 764             // Where N and M are small integer opcodes (OP1 ... OP_16)
 765             templateTuples.Add(
 766                 new Tuple<txnouttype, IEnumerable<byte>>(
 767                     txnouttype.TX_MULTISIG,
 768                     new byte[] {
 769                         (byte)instruction.OP_SMALLINTEGER,
 770                         (byte)instruction.OP_PUBKEYS,
 771                         (byte)instruction.OP_SMALLINTEGER,
 772                         (byte)instruction.OP_CHECKMULTISIG
 773                     })
 774             );
 775
 776             // Data-carrying output
 777             // OP_RETURN [up to 80 bytes of data]
 778             templateTuples.Add(
 779                 new Tuple<txnouttype, IEnumerable<byte>>(
 780                     txnouttype.TX_NULL_DATA,
 781                     new byte[] {
 782                         (byte)instruction.OP_RETURN,
 783                         (byte)instruction.OP_SMALLDATA
 784                     })
 785             );
 786
 787             // Nonstandard tx output
 788             typeRet = txnouttype.TX_NONSTANDARD;
 789
 790             foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
 791             {
 792                 CScript script1 = scriptPubKey;
 793                 CScript script2 = new CScript(templateTuple.Item2);
 794
 795                 instruction opcode1, opcode2;
 796
 797                 // Compare
 798                 ByteQueue bq1 = script1.GetByteQUeue();
 799                 ByteQueue bq2 = script2.GetByteQUeue();
 800
 801                 IEnumerable<byte> args1, args2;
 802
 803                 int last1 = script1.Bytes.Count() -1;
 804                 int last2 = script2.Bytes.Count() - 1;
 805
 806                 while (true)
 807                 {
 808                     if (bq1.CurrentIndex == last1 && bq2.CurrentIndex == last2)
 809                     {
 810                         // Found a match
 811                         typeRet = templateTuple.Item1;
 812                         if (typeRet == txnouttype.TX_MULTISIG)
 813                         {
 814                             // Additional checks for TX_MULTISIG:
 815                             byte m = solutions.First().First();
 816                             byte n = solutions.Last().First();
 817
 818                             if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
 819                             {
 820                                 return false;
 821                             }
 822                         }
 823                         return true;
 824                     }
 825
 826                     if (!GetOp(ref bq1, out opcode1, out args1))
 827                     {
 828                         break;
 829                     }
 830                     if (!GetOp(ref bq2, out opcode2, out args2))
 831                     {
 832                         break;
 833                     }
 834
 835                     // Template matching opcodes:
 836                     if (opcode2 == instruction.OP_PUBKEYS)
 837                     {
 838                         while (args1.Count() >= 33 && args1.Count() <= 120)
 839                         {
 840                             solutions.Add(args1);
 841                             if (!GetOp(ref bq1, out opcode1, out args1))
 842                             {
 843                                 break;
 844                             }
 845                         }
 846                         if (!GetOp(ref bq2, out opcode2, out args2))
 847                         {
 848                             break;
 849                         }
 850                         // Normal situation is to fall through
 851                         // to other if/else statements
 852                     }
 853                     if (opcode2 == instruction.OP_PUBKEY)
 854                     {
 855                         int PubKeyLen = args1.Count();
 856                         if (PubKeyLen < 33 || PubKeyLen > 120)
 857                         {
 858                             break;
 859                         }
 860                         solutions.Add(args1);
 861                     }
 862                     else if (opcode2 == instruction.OP_PUBKEYHASH)
 863                     {
 864                         if (args1.Count() != 20) // hash160 size
 865                         {
 866                             break;
 867                         }
 868                         solutions.Add(args1);
 869                     }
 870                     else if (opcode2 == instruction.OP_SMALLINTEGER)
 871                     {
 872                         // Single-byte small integer pushed onto solutions
 873                         try
 874                         {
 875                             byte n = (byte)DecodeOP_N(opcode1);
 876                             solutions.Add(new byte[] { n });
 877                         }
 878                         catch (Exception)
 879                         {
 880                             break;
 881                         }
 882                     }
 883                     else if (opcode2 == instruction.OP_SMALLDATA)
 884                     {
 885                         // small pushdata, <= 80 bytes
 886                         if (args1.Count() > 80)
 887                         {
 888                             break;
 889                         }
 890                     }
 891                     else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
 892                     {
 893                         // Others must match exactly
 894                         break;
 895                     }
 896                 }
 897             }
 898
 899             solutions.Clear();
 900             typeRet = txnouttype.TX_NONSTANDARD;
 901
 902             return false;
 903         }
 904
 905         public static Hash256 SignatureHash(CScript scriptCode, CTransaction txTo, int nIn, int nHashType)
 906         {
 907             if (nIn >= txTo.vin.Length)
 908             {
 909                 StringBuilder sb = new StringBuilder();
 910                 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
 911                 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
 912             }
 913
 914             CTransaction txTmp = new CTransaction(txTo);
 915
 916             // In case concatenating two scripts ends up with two codeseparators,
 917             // or an extra one at the end, this prevents all those possible incompatibilities.
 918             scriptCode.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
 919
 920             // Blank out other inputs' signatures
 921             for (int i = 0; i < txTmp.vin.Length; i++)
 922             {
 923                 txTmp.vin[i].scriptSig = new CScript();
 924             }
 925             txTmp.vin[nIn].scriptSig = scriptCode;
 926
 927             // Blank out some of the outputs
 928             if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
 929             {
 930                 // Wildcard payee
 931                 txTmp.vout = new CTxOut[0];
 932
 933                 // Let the others update at will
 934                 for (int i = 0; i < txTmp.vin.Length; i++)
 935                 {
 936                     if (i != nIn)
 937                     {
 938                         txTmp.vin[i].nSequence = 0;
 939                     }
 940                 }
 941             }
 942             else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
 943             {
 944                 // Only lock-in the txout payee at same index as txin
 945                 int nOut = nIn;
 946                 if (nOut >= txTmp.vout.Length)
 947                 {
 948                     StringBuilder sb = new StringBuilder();
 949                     sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
 950                     throw new ArgumentOutOfRangeException("nOut", sb.ToString());
 951                 }
 952                 Array.Resize(ref txTmp.vout, nOut + 1);
 953
 954                 for (int i = 0; i < nOut; i++)
 955                 {
 956                     txTmp.vout[i] = new CTxOut();
 957                 }
 958
 959                 // Let the others update at will
 960                 for (int i = 0; i < txTmp.vin.Length; i++)
 961                 {
 962                     if (i != nIn)
 963                     {
 964                         txTmp.vin[i].nSequence = 0;
 965                     }
 966                 }
 967             }
 968
 969             // Blank out other inputs completely, not recommended for open transactions
 970             if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
 971             {
 972                 txTmp.vin[0] = txTmp.vin[nIn];
 973                 Array.Resize(ref txTmp.vin, 1);
 974             }
 975
 976             // Serialize and hash
 977             List<byte> b = new List<byte>();
 978             b.AddRange(txTmp.Bytes);
 979             b.AddRange(BitConverter.GetBytes(nHashType));
 980
 981             return Hash256.Compute256(b);
 982         }
 983
 984         public class StackMachineException : Exception
 985         {
 986             public StackMachineException()
 987             {
 988             }
 989
 990             public StackMachineException(string message)
 991                 : base(message)
 992             {
 993             }
 994
 995             public StackMachineException(string message, Exception inner)
 996                 : base(message, inner)
 997             {
 998             }
 999         }
1000
1001
1002         //
1003         // Script is a stack machine (like Forth) that evaluates a predicate
1004         // returning a bool indicating valid or not.  There are no loops.
1005         //
1006
1007         /// <summary>
1008         /// Remove last element from stack
1009         /// </summary>
1010         /// <param name="stack">Stack reference</param>
1011         static void popstack(ref List<IEnumerable<byte>> stack)
1012         {
1013             int nCount = stack.Count;
1014             if (nCount == 0)
1015                 throw new StackMachineException("popstack() : stack empty");
1016             stack.RemoveAt(nCount - 1);
1017         }
1018
1019         /// <summary>
1020         /// Get element at specified stack depth
1021         /// </summary>
1022         /// <param name="stack">Stack reference</param>
1023         /// <param name="nDepth">Depth</param>
1024         /// <returns>Byte sequence</returns>
1025         static IEnumerable<byte> stacktop(ref List<IEnumerable<byte>> stack, int nDepth)
1026         {
1027             int nStackElement = stack.Count + nDepth;
1028
1029             if (nDepth >= 0)
1030             {
1031                 StringBuilder sb = new StringBuilder();
1032                 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
1033
1034                 throw new StackMachineException(sb.ToString());
1035             }
1036
1037             if (nStackElement < 0)
1038             {
1039                 StringBuilder sb = new StringBuilder();
1040                 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
1041
1042                 throw new StackMachineException(sb.ToString());
1043             }
1044
1045             return stack[nStackElement];
1046         }
1047
1048         /// <summary>
1049         /// Cast argument to boolean value
1050         /// </summary>
1051         /// <param name="value">Some byte sequence</param>
1052         /// <returns></returns>
1053         private static bool CastToBool(IEnumerable<byte> arg)
1054         {
1055             byte[] value = arg.ToArray();
1056
1057             for (var i = 0; i < value.Length; i++)
1058             {
1059                 if (value[i] != 0)
1060                 {
1061                     // Can be negative zero
1062                     if (i == value.Length - 1 && value[i] == 0x80)
1063                     {
1064                         return false;
1065                     }
1066
1067                     return true;
1068                 }
1069             }
1070
1071             return false;
1072         }
1073
1074         /// <summary>
1075         /// Cast argument to integer value
1076         /// </summary>
1077         /// <param name="value"></param>
1078         /// <returns></returns>
1079         private static BigInteger CastToBigInteger(IEnumerable<byte> value)
1080         {
1081             if (value.Count() > 4)
1082             {
1083                 throw new StackMachineException("CastToBigInteger() : overflow");
1084             }
1085
1086             return new BigInteger(value.ToArray());
1087         }
1088
1089         static bool EvalScript(ref List<IEnumerable<byte>> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
1090         {
1091             instruction opcode;
1092
1093             ByteQueue CodeQueue = script.GetByteQUeue();
1094
1095             List<bool> vfExec = new List<bool>();
1096             List<IEnumerable<byte>> altStack = new List<IEnumerable<byte>>();
1097
1098             byte[] falseBytes = new byte[0];
1099             byte[] trueBytes = new byte[] { 0x01 };
1100
1101             if (script.Bytes.Count() > 10000)
1102             {
1103                 return false; // Size limit failed
1104             }
1105
1106             int nOpCount = 0;
1107             int nCodeHashBegin = 0;
1108
1109             IEnumerable<byte> pushArg;
1110
1111             while (GetOp(ref CodeQueue, out opcode, out pushArg)) // Read instructions
1112             {
1113                 bool fExec = vfExec.IndexOf(false) != -1;
1114
1115                 if (pushArg.Count() > 520)
1116                 {
1117                     return false; // Script element size limit failed
1118                 }
1119
1120                 if (opcode > instruction.OP_16 && ++nOpCount > 201)
1121                 {
1122                     return false;
1123                 }
1124
1125                 if (fExec && 0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
1126                 {
1127                     stack.Add(pushArg); // Push argument to stack
1128                 }
1129                 else if (fExec || (instruction.OP_IF <= opcode && opcode <= instruction.OP_ENDIF))
1130                     switch (opcode)
1131                     {
1132                         //
1133                         // Disabled opcodes
1134                         //
1135                         case instruction.OP_CAT:
1136                         case instruction.OP_SUBSTR:
1137                         case instruction.OP_LEFT:
1138                         case instruction.OP_RIGHT:
1139                         case instruction.OP_INVERT:
1140                         case instruction.OP_AND:
1141                         case instruction.OP_OR:
1142                         case instruction.OP_XOR:
1143                         case instruction.OP_2MUL:
1144                         case instruction.OP_2DIV:
1145                         case instruction.OP_MUL:
1146                         case instruction.OP_DIV:
1147                         case instruction.OP_MOD:
1148                         case instruction.OP_LSHIFT:
1149                         case instruction.OP_RSHIFT:
1150                             return false;
1151
1152                         //
1153                         // Push integer instructions
1154                         //
1155                         case instruction.OP_1NEGATE:
1156                         case instruction.OP_1:
1157                         case instruction.OP_2:
1158                         case instruction.OP_3:
1159                         case instruction.OP_4:
1160                         case instruction.OP_5:
1161                         case instruction.OP_6:
1162                         case instruction.OP_7:
1163                         case instruction.OP_8:
1164                         case instruction.OP_9:
1165                         case instruction.OP_10:
1166                         case instruction.OP_11:
1167                         case instruction.OP_12:
1168                         case instruction.OP_13:
1169                         case instruction.OP_14:
1170                         case instruction.OP_15:
1171                         case instruction.OP_16:
1172                             {
1173                                 // ( -- value)
1174                                 BigInteger bn = DecodeOP_N(opcode);
1175                                 stack.Add(bn.ToByteArray());
1176                             }
1177                             break;
1178
1179                         //
1180                         // Extension
1181                         //
1182                         case instruction.OP_NOP:
1183                         case instruction.OP_NOP1:
1184                         case instruction.OP_NOP2:
1185                         case instruction.OP_NOP3:
1186                         case instruction.OP_NOP4:
1187                         case instruction.OP_NOP5:
1188                         case instruction.OP_NOP6:
1189                         case instruction.OP_NOP7:
1190                         case instruction.OP_NOP8:
1191                         case instruction.OP_NOP9:
1192                         case instruction.OP_NOP10:
1193                             {
1194                                 // Just do nothing
1195                                 break;
1196                             }
1197
1198                         //
1199                         // Control
1200                         //
1201                         case instruction.OP_IF:
1202                         case instruction.OP_NOTIF:
1203                             {
1204                                 // <expression> if [statements] [else [statements]] endif
1205                                 bool fValue = false;
1206                                 if (fExec)
1207                                 {
1208                                     if (stack.Count() < 1)
1209                                     {
1210                                         return false;
1211                                     }
1212                                     IEnumerable<byte> vch = stacktop(ref stack, -1);
1213                                     fValue = CastToBool(vch);
1214                                     if (opcode == instruction.OP_NOTIF)
1215                                     {
1216                                         fValue = !fValue;
1217                                     }
1218                                     popstack(ref stack);
1219                                 }
1220                                 vfExec.Add(fValue);
1221                             }
1222                             break;
1223
1224                         case instruction.OP_ELSE:
1225                             {
1226                                 int nExecCount = vfExec.Count();
1227                                 if (nExecCount == 0)
1228                                 {
1229                                     return false;
1230                                 }
1231                                 vfExec[nExecCount - 1] = !vfExec[nExecCount - 1];
1232                             }
1233                             break;
1234
1235                         case instruction.OP_ENDIF:
1236                             {
1237                                 int nExecCount = vfExec.Count();
1238                                 if (nExecCount == 0)
1239                                 {
1240                                     return false;
1241                                 }
1242                                 vfExec.RemoveAt(nExecCount - 1);
1243                             }
1244                             break;
1245
1246                         case instruction.OP_VERIFY:
1247                             {
1248                                 // (true -- ) or
1249                                 // (false -- false) and return
1250                                 if (stack.Count() < 1)
1251                                 {
1252                                     return false;
1253                                 }
1254
1255                                 bool fValue = CastToBool(stacktop(ref stack, -1));
1256                                 if (fValue)
1257                                 {
1258                                     popstack(ref stack);
1259                                 }
1260                                 else
1261                                 {
1262                                     return false;
1263                                 }
1264                             }
1265                             break;
1266
1267                         case instruction.OP_RETURN:
1268                             {
1269                                 return false;
1270                             }
1271
1272                         //
1273                         // Stack ops
1274                         //
1275                         case instruction.OP_TOALTSTACK:
1276                             {
1277                                 if (stack.Count() < 1)
1278                                 {
1279                                     return false;
1280                                 }
1281                                 altStack.Add(stacktop(ref stack, -1));
1282                                 popstack(ref stack);
1283                             }
1284                             break;
1285
1286                         case instruction.OP_FROMALTSTACK:
1287                             {
1288                                 if (altStack.Count() < 1)
1289                                 {
1290                                     return false;
1291                                 }
1292                                 stack.Add(stacktop(ref stack, -1));
1293                                 popstack(ref altStack);
1294                             }
1295                             break;
1296
1297                         case instruction.OP_2DROP:
1298                             {
1299                                 // (x1 x2 -- )
1300                                 if (stack.Count() < 2)
1301                                 {
1302                                     return false;
1303                                 }
1304                                 popstack(ref stack);
1305                                 popstack(ref stack);
1306                             }
1307                             break;
1308
1309                         case instruction.OP_2DUP:
1310                             {
1311                                 // (x1 x2 -- x1 x2 x1 x2)
1312                                 if (stack.Count() < 2)
1313                                 {
1314                                     return false;
1315                                 }
1316                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1317                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1318                                 stack.Add(vch1);
1319                                 stack.Add(vch2);
1320                             }
1321                             break;
1322
1323                         case instruction.OP_3DUP:
1324                             {
1325                                 // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
1326                                 if (stack.Count() < 3)
1327                                 {
1328                                     return false;
1329                                 }
1330                                 IEnumerable<byte> vch1 = stacktop(ref stack, -3);
1331                                 IEnumerable<byte> vch2 = stacktop(ref stack, -2);
1332                                 IEnumerable<byte> vch3 = stacktop(ref stack, -1);
1333                                 stack.Add(vch1);
1334                                 stack.Add(vch2);
1335                                 stack.Add(vch3);
1336                             }
1337                             break;
1338
1339                         case instruction.OP_2OVER:
1340                             {
1341                                 // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
1342                                 if (stack.Count() < 4)
1343                                 {
1344                                     return false;
1345                                 }
1346                                 IEnumerable<byte> vch1 = stacktop(ref stack, -4);
1347                                 IEnumerable<byte> vch2 = stacktop(ref stack, -3);
1348                                 stack.Add(vch1);
1349                                 stack.Add(vch2);
1350                             }
1351                             break;
1352
1353                         case instruction.OP_2ROT:
1354                             {
1355                                 int nStackDepth = stack.Count();
1356                                 // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
1357                                 if (nStackDepth < 6)
1358                                 {
1359                                     return false;
1360                                 }
1361                                 IEnumerable<byte> vch1 = stacktop(ref stack, -6);
1362                                 IEnumerable<byte> vch2 = stacktop(ref stack, -5);
1363                                 stack.RemoveRange(nStackDepth - 6, 2);
1364                                 stack.Add(vch1);
1365                                 stack.Add(vch2);
1366                             }
1367                             break;
1368
1369                         case instruction.OP_2SWAP:
1370                             {
1371                                 // (x1 x2 x3 x4 -- x3 x4 x1 x2)
1372                                 int nStackDepth = stack.Count();
1373                                 if (nStackDepth < 4)
1374                                 {
1375                                     return false;
1376                                 }
1377                                 stack.Swap(nStackDepth - 4, nStackDepth - 2);
1378                                 stack.Swap(nStackDepth - 3, nStackDepth - 1);
1379                             }
1380                             break;
1381
1382                         case instruction.OP_IFDUP:
1383                             {
1384                                 // (x - 0 | x x)
1385                                 if (stack.Count() < 1)
1386                                 {
1387                                     return false;
1388                                 }
1389
1390                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1391
1392                                 if (CastToBool(vch))
1393                                 {
1394                                     stack.Add(vch);
1395                                 }
1396                             }
1397                             break;
1398
1399                         case instruction.OP_DEPTH:
1400                             {
1401                                 // -- stacksize
1402                                 BigInteger bn = new BigInteger((ushort)stack.Count());
1403                                 stack.Add(bn.ToByteArray());
1404                             }
1405                             break;
1406
1407                         case instruction.OP_DROP:
1408                             {
1409                                 // (x -- )
1410                                 if (stack.Count() < 1)
1411                                 {
1412                                     return false;
1413                                 }
1414
1415                                 popstack(ref stack);
1416                             }
1417                             break;
1418
1419                         case instruction.OP_DUP:
1420                             {
1421                                 // (x -- x x)
1422                                 if (stack.Count() < 1)
1423                                 {
1424                                     return false;
1425                                 }
1426
1427                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1428                                 stack.Add(vch);
1429                             }
1430                             break;
1431
1432                         case instruction.OP_NIP:
1433                             {
1434                                 // (x1 x2 -- x2)
1435                                 int nStackDepth = stack.Count();
1436                                 if (nStackDepth < 2)
1437                                 {
1438                                     return false;
1439                                 }
1440
1441                                 stack.RemoveAt(nStackDepth - 2);
1442                             }
1443                             break;
1444
1445                         case instruction.OP_OVER:
1446                             {
1447                                 // (x1 x2 -- x1 x2 x1)
1448                                 if (stack.Count() < 2)
1449                                 {
1450                                     return false;
1451                                 }
1452
1453                                 IEnumerable<byte> vch = stacktop(ref stack, -2);
1454                                 stack.Add(vch);
1455                             }
1456                             break;
1457
1458                         case instruction.OP_PICK:
1459                         case instruction.OP_ROLL:
1460                             {
1461                                 // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
1462                                 // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
1463
1464                                 int nStackDepth = stack.Count();
1465                                 if (nStackDepth < 2)
1466                                 {
1467                                     return false;
1468                                 }
1469
1470                                 int n = (int)CastToBigInteger(stacktop(ref stack, -1));
1471                                 popstack(ref stack);
1472
1473                                 if (n < 0 || n >= stack.Count())
1474                                 {
1475                                     return false;
1476                                 }
1477
1478                                 IEnumerable<byte> vch = stacktop(ref stack, -n - 1);
1479                                 if (opcode == instruction.OP_ROLL)
1480                                 {
1481                                     stack.RemoveAt(nStackDepth - n - 1);
1482                                 }
1483
1484                                 stack.Add(vch);
1485                             }
1486                             break;
1487
1488                         case instruction.OP_ROT:
1489                             {
1490                                 // (x1 x2 x3 -- x2 x3 x1)
1491                                 //  x2 x1 x3  after first swap
1492                                 //  x2 x3 x1  after second swap
1493                                 int nStackDepth = stack.Count();
1494                                 if (nStackDepth < 3)
1495                                 {
1496                                     return false;
1497                                 }
1498                                 stack.Swap(nStackDepth - 3, nStackDepth - 2);
1499                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1500
1501                             }
1502                             break;
1503
1504                         case instruction.OP_SWAP:
1505                             {
1506                                 // (x1 x2 -- x2 x1)
1507                                 int nStackDepth = stack.Count();
1508                                 if (nStackDepth < 2)
1509                                 {
1510                                     return false;
1511                                 }
1512                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1513                             }
1514                             break;
1515
1516                         case instruction.OP_TUCK:
1517                             {
1518                                 // (x1 x2 -- x2 x1 x2)
1519                                 int nStackDepth = stack.Count();
1520                                 if (nStackDepth < 2)
1521                                 {
1522                                     return false;
1523                                 }
1524                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1525                                 stack.Insert(nStackDepth - 2, vch);
1526                             }
1527                             break;
1528
1529
1530                         case instruction.OP_SIZE:
1531                             {
1532                                 // (in -- in size)
1533                                 if (stack.Count() < 1)
1534                                 {
1535                                     return false;
1536                                 }
1537
1538                                 BigInteger bnSize = new BigInteger((ushort)stacktop(ref stack, -1).Count());
1539                                 stack.Add(bnSize.ToByteArray());
1540                             }
1541                             break;
1542
1543
1544                         //
1545                         // Bitwise logic
1546                         //
1547                         case instruction.OP_EQUAL:
1548                         case instruction.OP_EQUALVERIFY:
1549                             //case instruction.OP_NOTEQUAL: // use OP_NUMNOTEQUAL
1550                             {
1551                                 // (x1 x2 - bool)
1552                                 if (stack.Count() < 2)
1553                                 {
1554                                     return false;
1555                                 }
1556
1557                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1558                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1559                                 bool fEqual = (vch1 == vch2);
1560                                 // OP_NOTEQUAL is disabled because it would be too easy to say
1561                                 // something like n != 1 and have some wiseguy pass in 1 with extra
1562                                 // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
1563                                 //if (opcode == instruction.OP_NOTEQUAL)
1564                                 //    fEqual = !fEqual;
1565                                 popstack(ref stack);
1566                                 popstack(ref stack);
1567                                 stack.Add(fEqual ? trueBytes : falseBytes);
1568
1569                                 if (opcode == instruction.OP_EQUALVERIFY)
1570                                 {
1571                                     if (fEqual)
1572                                     {
1573                                         popstack(ref stack);
1574                                     }
1575                                     else
1576                                     {
1577                                         return false;
1578                                     }
1579                                 }
1580                             }
1581                             break;
1582
1583
1584                         //
1585                         // Numeric
1586                         //
1587                         case instruction.OP_1ADD:
1588                         case instruction.OP_1SUB:
1589                         case instruction.OP_NEGATE:
1590                         case instruction.OP_ABS:
1591                         case instruction.OP_NOT:
1592                         case instruction.OP_0NOTEQUAL:
1593                             {
1594                                 // (in -- out)
1595                                 if (stack.Count() < 1)
1596                                 {
1597                                     return false;
1598                                 }
1599
1600                                 BigInteger bn = CastToBigInteger(stacktop(ref stack, -1));
1601                                 switch (opcode)
1602                                 {
1603                                     case instruction.OP_1ADD:
1604                                         bn = bn + 1;
1605                                         break;
1606                                     case instruction.OP_1SUB:
1607                                         bn = bn - 1;
1608                                         break;
1609                                     case instruction.OP_NEGATE:
1610                                         bn = -bn;
1611                                         break;
1612                                     case instruction.OP_ABS:
1613                                         bn = BigInteger.Abs(bn);
1614                                         break;
1615                                     case instruction.OP_NOT:
1616                                         bn = bn == 0 ? 1 : 0;
1617                                         break;
1618                                     case instruction.OP_0NOTEQUAL:
1619                                         bn = bn != 0 ? 1 : 0;
1620                                         break;
1621
1622                                     default:
1623                                         throw new StackMachineException("invalid instruction");
1624                                 }
1625
1626                                 popstack(ref stack);
1627                                 stack.Add(bn.ToByteArray());
1628                             }
1629                             break;
1630
1631                         case instruction.OP_ADD:
1632                         case instruction.OP_SUB:
1633                         case instruction.OP_BOOLAND:
1634                         case instruction.OP_BOOLOR:
1635                         case instruction.OP_NUMEQUAL:
1636                         case instruction.OP_NUMEQUALVERIFY:
1637                         case instruction.OP_NUMNOTEQUAL:
1638                         case instruction.OP_LESSTHAN:
1639                         case instruction.OP_GREATERTHAN:
1640                         case instruction.OP_LESSTHANOREQUAL:
1641                         case instruction.OP_GREATERTHANOREQUAL:
1642                         case instruction.OP_MIN:
1643                         case instruction.OP_MAX:
1644                             {
1645                                 // (x1 x2 -- out)
1646                                 if (stack.Count() < 2)
1647                                 {
1648                                     return false;
1649                                 }
1650
1651                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -2));
1652                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -1));
1653                                 BigInteger bn = 0;
1654
1655                                 switch (opcode)
1656                                 {
1657                                     case instruction.OP_ADD:
1658                                         bn = bn1 + bn2;
1659                                         break;
1660                                     case instruction.OP_SUB:
1661                                         bn = bn1 - bn2;
1662                                         break;
1663                                     case instruction.OP_BOOLAND:
1664                                         bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1665                                         break;
1666                                     case instruction.OP_BOOLOR:
1667                                         bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1668                                         break;
1669                                     case instruction.OP_NUMEQUAL:
1670                                         bn = (bn1 == bn2) ? 1 : 0;
1671                                         break;
1672                                     case instruction.OP_NUMEQUALVERIFY:
1673                                         bn = (bn1 == bn2) ? 1 : 0;
1674                                         break;
1675                                     case instruction.OP_NUMNOTEQUAL:
1676                                         bn = (bn1 != bn2) ? 1 : 0;
1677                                         break;
1678                                     case instruction.OP_LESSTHAN:
1679                                         bn = (bn1 < bn2) ? 1 : 0;
1680                                         break;
1681                                     case instruction.OP_GREATERTHAN:
1682                                         bn = (bn1 > bn2) ? 1 : 0;
1683                                         break;
1684                                     case instruction.OP_LESSTHANOREQUAL:
1685                                         bn = (bn1 <= bn2) ? 1 : 0;
1686                                         break;
1687                                     case instruction.OP_GREATERTHANOREQUAL:
1688                                         bn = (bn1 >= bn2) ? 1 : 0;
1689                                         break;
1690                                     case instruction.OP_MIN:
1691                                         bn = (bn1 < bn2 ? bn1 : bn2);
1692                                         break;
1693                                     case instruction.OP_MAX:
1694                                         bn = (bn1 > bn2 ? bn1 : bn2);
1695                                         break;
1696
1697                                     default:
1698                                         throw new StackMachineException("invalid instruction");
1699                                 }
1700
1701                                 popstack(ref stack);
1702                                 popstack(ref stack);
1703                                 stack.Add(bn.ToByteArray());
1704
1705                                 if (opcode == instruction.OP_NUMEQUALVERIFY)
1706                                 {
1707                                     if (CastToBool(stacktop(ref stack, -1)))
1708                                     {
1709                                         popstack(ref stack);
1710                                     }
1711                                     else
1712                                     {
1713                                         return false;
1714                                     }
1715                                 }
1716                             }
1717                             break;
1718
1719                         case instruction.OP_WITHIN:
1720                             {
1721                                 // (x min max -- out)
1722                                 if (stack.Count() < 3)
1723                                     return false;
1724                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -3));
1725                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -2));
1726                                 BigInteger bn3 = CastToBigInteger(stacktop(ref stack, -1));
1727                                 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1728                                 popstack(ref stack);
1729                                 popstack(ref stack);
1730                                 popstack(ref stack);
1731                                 stack.Add(fValue ? trueBytes : falseBytes);
1732                             }
1733                             break;
1734
1735
1736                         //
1737                         // Crypto
1738                         //
1739                         case instruction.OP_RIPEMD160:
1740                         case instruction.OP_SHA1:
1741                         case instruction.OP_SHA256:
1742                         case instruction.OP_HASH160:
1743                         case instruction.OP_HASH256:
1744                             {
1745                                 // (in -- hash)
1746                                 if (stack.Count() < 1)
1747                                     return false;
1748                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1749                                 IEnumerable<byte> vchHash = null;
1750                                 if (opcode == instruction.OP_RIPEMD160)
1751                                 {
1752                                     RIPEMD160 hash = RIPEMD160.Compute160(vch);
1753                                     vchHash = hash.hashBytes;
1754                                 }
1755                                 else if (opcode == instruction.OP_SHA1)
1756                                 {
1757                                     SHA1 hash = SHA1.Compute1(vch);
1758                                     vchHash = hash.hashBytes;
1759                                 }
1760                                 else if (opcode == instruction.OP_SHA256)
1761                                 {
1762                                     SHA256 hash = SHA256.Compute256(vch);
1763                                     vchHash = hash.hashBytes;
1764                                 }
1765                                 else if (opcode == instruction.OP_HASH160)
1766                                 {
1767                                     Hash160 hash = Hash160.Compute160(vch);
1768                                     vchHash = hash.hashBytes;
1769                                 }
1770                                 else if (opcode == instruction.OP_HASH256)
1771                                 {
1772                                     Hash256 hash = Hash256.Compute256(vch);
1773                                     vchHash = hash.hashBytes;
1774                                 }
1775                                 popstack(ref stack);
1776                                 stack.Add(vchHash);
1777                             }
1778                             break;
1779
1780                         case instruction.OP_CODESEPARATOR:
1781                             {
1782                                 // Hash starts after the code separator
1783                                 nCodeHashBegin = CodeQueue.CurrentIndex;
1784                             }
1785                             break;
1786
1787                         case instruction.OP_CHECKSIG:
1788                         case instruction.OP_CHECKSIGVERIFY:
1789                             {
1790                                 // (sig pubkey -- bool)
1791                                 if (stack.Count() < 2)
1792                                 {
1793                                     return false;
1794                                 }
1795
1796                                 IList<byte> sigBytes = stacktop(ref stack, -2).ToList();
1797                                 IList<byte> pubkeyBytes = stacktop(ref stack, -1).ToList();
1798
1799                                 // Subset of script starting at the most recent codeseparator
1800                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1801
1802                                 // There's no way for a signature to sign itself
1803                                 scriptCode.RemovePattern(sigBytes);
1804
1805                                 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes.ToList(), flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1806
1807                                 popstack(ref stack);
1808                                 popstack(ref stack);
1809                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1810                                 if (opcode == instruction.OP_CHECKSIGVERIFY)
1811                                 {
1812                                     if (fSuccess)
1813                                     {
1814                                         popstack(ref stack);
1815                                     }
1816                                     else
1817                                     {
1818                                         return false;
1819                                     }
1820                                 }
1821                             }
1822                             break;
1823
1824                         case instruction.OP_CHECKMULTISIG:
1825                         case instruction.OP_CHECKMULTISIGVERIFY:
1826                             {
1827                                 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1828
1829                                 int i = 1;
1830                                 if (stack.Count() < i)
1831                                 {
1832                                     return false;
1833                                 }
1834
1835                                 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1836                                 if (nKeysCount < 0 || nKeysCount > 20)
1837                                 {
1838                                     return false;
1839                                 }
1840                                 nOpCount += nKeysCount;
1841                                 if (nOpCount > 201)
1842                                 {
1843                                     return false;
1844                                 }
1845                                 int ikey = ++i;
1846                                 i += nKeysCount;
1847                                 if (stack.Count() < i)
1848                                 {
1849                                     return false;
1850                                 }
1851
1852                                 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1853                                 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1854                                 {
1855                                     return false;
1856                                 }
1857                                 int isig = ++i;
1858                                 i += nSigsCount;
1859                                 if (stack.Count() < i)
1860                                 {
1861                                     return false;
1862                                 }
1863
1864                                 // Subset of script starting at the most recent codeseparator
1865                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1866
1867                                 // There is no way for a signature to sign itself, so we need to drop the signatures
1868                                 for (int k = 0; k < nSigsCount; k++)
1869                                 {
1870                                     IEnumerable<byte> vchSig = stacktop(ref stack, -isig - k);
1871                                     scriptCode.RemovePattern(vchSig.ToList());
1872                                 }
1873
1874                                 bool fSuccess = true;
1875                                 while (fSuccess && nSigsCount > 0)
1876                                 {
1877                                     IList<byte> sigBytes = stacktop(ref stack, -isig).ToList();
1878                                     IList<byte> pubKeyBytes = stacktop(ref stack, -ikey).ToList();
1879
1880                                     // Check signature
1881                                     bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes.ToList(), flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1882
1883                                     if (fOk)
1884                                     {
1885                                         isig++;
1886                                         nSigsCount--;
1887                                     }
1888                                     ikey++;
1889                                     nKeysCount--;
1890
1891                                     // If there are more signatures left than keys left,
1892                                     // then too many signatures have failed
1893                                     if (nSigsCount > nKeysCount)
1894                                     {
1895                                         fSuccess = false;
1896                                     }
1897                                 }
1898
1899                                 while (i-- > 1)
1900                                 {
1901                                     popstack(ref stack);
1902                                 }
1903
1904                                 // A bug causes CHECKMULTISIG to consume one extra argument
1905                                 // whose contents were not checked in any way.
1906                                 //
1907                                 // Unfortunately this is a potential source of mutability,
1908                                 // so optionally verify it is exactly equal to zero prior
1909                                 // to removing it from the stack.
1910                                 if (stack.Count() < 1)
1911                                 {
1912                                     return false;
1913                                 }
1914                                 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1915                                 {
1916                                     return false; // CHECKMULTISIG dummy argument not null
1917                                 }
1918                                 popstack(ref stack);
1919
1920                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1921
1922                                 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1923                                 {
1924                                     if (fSuccess)
1925                                     {
1926                                         popstack(ref stack);
1927                                     }
1928                                     else
1929                                     {
1930                                         return false;
1931                                     }
1932                                 }
1933                             }
1934                             break;
1935
1936                         default:
1937                             return false;
1938                     }
1939
1940                 // Size limits
1941                 if (stack.Count() + altStack.Count() > 1000)
1942                 {
1943                     return false;
1944                 }
1945             }
1946
1947
1948             if (vfExec.Count() == 0)
1949             {
1950                 return false;
1951             }
1952
1953             return true;
1954         }
1955
1956
1957         static bool IsCanonicalPubKey(IList<byte> pubKeyBytes, int flags)
1958         {
1959             if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1960                 return true;
1961
1962             if (pubKeyBytes.Count < 33)
1963                 return false;  // Non-canonical public key: too short
1964             if (pubKeyBytes[0] == 0x04)
1965             {
1966                 if (pubKeyBytes.Count != 65)
1967                     return false; // Non-canonical public key: invalid length for uncompressed key
1968             }
1969             else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1970             {
1971                 if (pubKeyBytes.Count != 33)
1972                     return false; // Non-canonical public key: invalid length for compressed key
1973             }
1974             else
1975             {
1976                 return false; // Non-canonical public key: compressed nor uncompressed
1977             }
1978             return true;
1979         }
1980
1981         static bool IsCanonicalSignature(IList<byte> sigBytes, int flags)
1982         {
1983             // STUB
1984
1985             return true;
1986         }
1987
1988         static bool CheckSig(IList<byte> vchSig, IList<byte> vchPubKey, CScript scriptCode, CTransaction txTo, int nIn, int nHashType, int flags)
1989         {
1990             CPubKey pubkey;
1991
1992             try
1993             {
1994                 // Trying to initialize the public key instance
1995
1996                 pubkey = new CPubKey(vchPubKey);
1997             }
1998             catch (Exception)
1999             {
2000                 // Exception occurred while initializing the public key
2001
2002                 return false;
2003             }
2004
2005             if (!pubkey.IsValid)
2006             {
2007                 return false;
2008             }
2009
2010             if (vchSig.Count == 0)
2011             {
2012                 return false;
2013             }
2014
2015             // Hash type is one byte tacked on to the end of the signature
2016             if (nHashType == 0)
2017             {
2018                 nHashType = vchSig.Last();
2019             }
2020             else if (nHashType != vchSig.Last())
2021             {
2022                 return false;
2023             }
2024
2025             // Remove hash type
2026             vchSig.RemoveAt(vchSig.Count - 1);
2027
2028             Hash256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
2029
2030             if (!pubkey.VerifySignature(sighash, vchSig))
2031             {
2032                 return false;
2033             }
2034
2035             return true;
2036         }
2037     };
2038 }