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 ArgumentException("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 ArgumentException("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                         int PubKeyLen = args1.Count();
 835                         while (PubKeyLen >= 33 && PubKeyLen <= 120)
 836                         {
 837                             solutions.Add(args1);
 838                             if (!GetOp(ref bq1, out opcode1, out args1))
 839                             {
 840                                 break;
 841                             }
 842                         }
 843                         if (!GetOp(ref bq2, out opcode2, out args2))
 844                             break;
 845                         // Normal situation is to fall through
 846                         // to other if/else statements
 847                     }
 848                     if (opcode2 == instruction.OP_PUBKEY)
 849                     {
 850                         int PubKeyLen = args1.Count();
 851                         if (PubKeyLen < 33 || PubKeyLen > 120)
 852                         {
 853                             break;
 854                         }
 855                         solutions.Add(args1);
 856                     }
 857                     else if (opcode2 == instruction.OP_PUBKEYHASH)
 858                     {
 859                         if (args1.Count() != 20) // hash160 size
 860                         {
 861                             break;
 862                         }
 863                         solutions.Add(args1);
 864                     }
 865                     else if (opcode2 == instruction.OP_SMALLINTEGER)
 866                     {
 867                         // Single-byte small integer pushed onto solutions
 868                         try
 869                         {
 870                             byte n = (byte)DecodeOP_N(opcode1);
 871                             solutions.Add(new byte[] { n });
 872                         }
 873                         catch (ArgumentException)
 874                         {
 875                             break;
 876                         }
 877                     }
 878                     else if (opcode2 == instruction.OP_SMALLDATA)
 879                     {
 880                         // small pushdata, <= 80 bytes
 881                         if (args1.Count() > 80)
 882                         {
 883                             break;
 884                         }
 885                     }
 886                     else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
 887                     {
 888                         // Others must match exactly
 889                         break;
 890                     }
 891                 }
 892             }
 893
 894             solutions.Clear();
 895             typeRet = txnouttype.TX_NONSTANDARD;
 896
 897             return false;
 898         }
 899
 900         public static Hash256 SignatureHash(CScript scriptCode, CTransaction txTo, int nIn, int nHashType)
 901         {
 902             if (nIn >= txTo.vin.Length)
 903             {
 904                 StringBuilder sb = new StringBuilder();
 905                 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
 906                 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
 907             }
 908
 909             CTransaction txTmp = new CTransaction(txTo);
 910
 911             // In case concatenating two scripts ends up with two codeseparators,
 912             // or an extra one at the end, this prevents all those possible incompatibilities.
 913             scriptCode.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
 914
 915             // Blank out other inputs' signatures
 916             for (int i = 0; i < txTmp.vin.Length; i++)
 917             {
 918                 txTmp.vin[i].scriptSig = new CScript();
 919             }
 920             txTmp.vin[nIn].scriptSig = scriptCode;
 921
 922             // Blank out some of the outputs
 923             if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
 924             {
 925                 // Wildcard payee
 926                 txTmp.vout = new CTxOut[0];
 927
 928                 // Let the others update at will
 929                 for (int i = 0; i < txTmp.vin.Length; i++)
 930                 {
 931                     if (i != nIn)
 932                     {
 933                         txTmp.vin[i].nSequence = 0;
 934                     }
 935                 }
 936             }
 937             else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
 938             {
 939                 // Only lock-in the txout payee at same index as txin
 940                 int nOut = nIn;
 941                 if (nOut >= txTmp.vout.Length)
 942                 {
 943                     StringBuilder sb = new StringBuilder();
 944                     sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
 945                     throw new ArgumentOutOfRangeException("nOut", sb.ToString());
 946                 }
 947                 Array.Resize(ref txTmp.vout, nOut + 1);
 948
 949                 for (int i = 0; i < nOut; i++)
 950                 {
 951                     txTmp.vout[i] = new CTxOut();
 952                 }
 953
 954                 // Let the others update at will
 955                 for (int i = 0; i < txTmp.vin.Length; i++)
 956                 {
 957                     if (i != nIn)
 958                     {
 959                         txTmp.vin[i].nSequence = 0;
 960                     }
 961                 }
 962             }
 963
 964             // Blank out other inputs completely, not recommended for open transactions
 965             if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
 966             {
 967                 txTmp.vin[0] = txTmp.vin[nIn];
 968                 Array.Resize(ref txTmp.vin, 1);
 969             }
 970
 971             // Serialize and hash
 972             List<byte> b = new List<byte>();
 973             b.AddRange(txTmp.Bytes);
 974             b.AddRange(BitConverter.GetBytes(nHashType));
 975
 976             return Hash256.Compute256(b);
 977         }
 978
 979         public class StackMachineException : Exception
 980         {
 981             public StackMachineException()
 982             {
 983             }
 984
 985             public StackMachineException(string message)
 986                 : base(message)
 987             {
 988             }
 989
 990             public StackMachineException(string message, Exception inner)
 991                 : base(message, inner)
 992             {
 993             }
 994         }
 995
 996
 997         //
 998         // Script is a stack machine (like Forth) that evaluates a predicate
 999         // returning a bool indicating valid or not.  There are no loops.
1000         //
1001
1002         /// <summary>
1003         /// Remove last element from stack
1004         /// </summary>
1005         /// <param name="stack">Stack reference</param>
1006         static void popstack(ref List<IEnumerable<byte>> stack)
1007         {
1008             int nCount = stack.Count;
1009             if (nCount == 0)
1010                 throw new StackMachineException("popstack() : stack empty");
1011             stack.RemoveAt(nCount - 1);
1012         }
1013
1014         /// <summary>
1015         /// Get element at specified stack depth
1016         /// </summary>
1017         /// <param name="stack">Stack reference</param>
1018         /// <param name="nDepth">Depth</param>
1019         /// <returns>Byte sequence</returns>
1020         static IEnumerable<byte> stacktop(ref List<IEnumerable<byte>> stack, int nDepth)
1021         {
1022             int nStackElement = stack.Count + nDepth;
1023
1024             if (nDepth >= 0)
1025             {
1026                 StringBuilder sb = new StringBuilder();
1027                 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
1028
1029                 throw new StackMachineException(sb.ToString());
1030             }
1031
1032             if (nStackElement < 0)
1033             {
1034                 StringBuilder sb = new StringBuilder();
1035                 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
1036
1037                 throw new StackMachineException(sb.ToString());
1038             }
1039
1040             return stack[nStackElement];
1041         }
1042
1043         /// <summary>
1044         /// Cast argument to boolean value
1045         /// </summary>
1046         /// <param name="value">Some byte sequence</param>
1047         /// <returns></returns>
1048         private static bool CastToBool(IEnumerable<byte> arg)
1049         {
1050             byte[] value = arg.ToArray();
1051
1052             for (var i = 0; i < value.Length; i++)
1053             {
1054                 if (value[i] != 0)
1055                 {
1056                     // Can be negative zero
1057                     if (i == value.Length - 1 && value[i] == 0x80)
1058                     {
1059                         return false;
1060                     }
1061
1062                     return true;
1063                 }
1064             }
1065
1066             return false;
1067         }
1068
1069         /// <summary>
1070         /// Cast argument to integer value
1071         /// </summary>
1072         /// <param name="value"></param>
1073         /// <returns></returns>
1074         private static BigInteger CastToBigInteger(IEnumerable<byte> value)
1075         {
1076             if (value.Count() > 4)
1077             {
1078                 throw new StackMachineException("CastToBigInteger() : overflow");
1079             }
1080
1081             return new BigInteger(value.ToArray());
1082         }
1083
1084         static bool EvalScript(ref List<IEnumerable<byte>> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
1085         {
1086             instruction opcode;
1087
1088             ByteQueue CodeQueue = script.GetByteQUeue();
1089
1090             List<bool> vfExec = new List<bool>();
1091             List<IEnumerable<byte>> altStack = new List<IEnumerable<byte>>();
1092
1093             byte[] falseBytes = new byte[0];
1094             byte[] trueBytes = new byte[] { 0x01 };
1095
1096             if (script.Bytes.Count() > 10000)
1097             {
1098                 return false; // Size limit failed
1099             }
1100
1101             int nOpCount = 0;
1102             int nCodeHashBegin = 0;
1103
1104             IEnumerable<byte> pushArg;
1105
1106             while (GetOp(ref CodeQueue, out opcode, out pushArg)) // Read instructions
1107             {
1108                 bool fExec = vfExec.IndexOf(false) != -1;
1109
1110                 if (pushArg.Count() > 520)
1111                 {
1112                     return false; // Script element size limit failed
1113                 }
1114
1115                 if (opcode > instruction.OP_16 && ++nOpCount > 201)
1116                 {
1117                     return false;
1118                 }
1119
1120                 if (fExec && 0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
1121                 {
1122                     stack.Add(pushArg); // Push argument to stack
1123                 }
1124                 else if (fExec || (instruction.OP_IF <= opcode && opcode <= instruction.OP_ENDIF))
1125                     switch (opcode)
1126                     {
1127                         //
1128                         // Disabled opcodes
1129                         //
1130                         case instruction.OP_CAT:
1131                         case instruction.OP_SUBSTR:
1132                         case instruction.OP_LEFT:
1133                         case instruction.OP_RIGHT:
1134                         case instruction.OP_INVERT:
1135                         case instruction.OP_AND:
1136                         case instruction.OP_OR:
1137                         case instruction.OP_XOR:
1138                         case instruction.OP_2MUL:
1139                         case instruction.OP_2DIV:
1140                         case instruction.OP_MUL:
1141                         case instruction.OP_DIV:
1142                         case instruction.OP_MOD:
1143                         case instruction.OP_LSHIFT:
1144                         case instruction.OP_RSHIFT:
1145                             return false;
1146
1147                         //
1148                         // Push integer instructions
1149                         //
1150                         case instruction.OP_1NEGATE:
1151                         case instruction.OP_1:
1152                         case instruction.OP_2:
1153                         case instruction.OP_3:
1154                         case instruction.OP_4:
1155                         case instruction.OP_5:
1156                         case instruction.OP_6:
1157                         case instruction.OP_7:
1158                         case instruction.OP_8:
1159                         case instruction.OP_9:
1160                         case instruction.OP_10:
1161                         case instruction.OP_11:
1162                         case instruction.OP_12:
1163                         case instruction.OP_13:
1164                         case instruction.OP_14:
1165                         case instruction.OP_15:
1166                         case instruction.OP_16:
1167                             {
1168                                 // ( -- value)
1169                                 BigInteger bn = DecodeOP_N(opcode);
1170                                 stack.Add(bn.ToByteArray());
1171                             }
1172                             break;
1173
1174                         //
1175                         // Extension
1176                         //
1177                         case instruction.OP_NOP:
1178                         case instruction.OP_NOP1:
1179                         case instruction.OP_NOP2:
1180                         case instruction.OP_NOP3:
1181                         case instruction.OP_NOP4:
1182                         case instruction.OP_NOP5:
1183                         case instruction.OP_NOP6:
1184                         case instruction.OP_NOP7:
1185                         case instruction.OP_NOP8:
1186                         case instruction.OP_NOP9:
1187                         case instruction.OP_NOP10:
1188                             {
1189                                 // Just do nothing
1190                                 break;
1191                             }
1192
1193                         //
1194                         // Control
1195                         //
1196                         case instruction.OP_IF:
1197                         case instruction.OP_NOTIF:
1198                             {
1199                                 // <expression> if [statements] [else [statements]] endif
1200                                 bool fValue = false;
1201                                 if (fExec)
1202                                 {
1203                                     if (stack.Count() < 1)
1204                                     {
1205                                         return false;
1206                                     }
1207                                     IEnumerable<byte> vch = stacktop(ref stack, -1);
1208                                     fValue = CastToBool(vch);
1209                                     if (opcode == instruction.OP_NOTIF)
1210                                     {
1211                                         fValue = !fValue;
1212                                     }
1213                                     popstack(ref stack);
1214                                 }
1215                                 vfExec.Add(fValue);
1216                             }
1217                             break;
1218
1219                         case instruction.OP_ELSE:
1220                             {
1221                                 int nExecCount = vfExec.Count();
1222                                 if (nExecCount == 0)
1223                                 {
1224                                     return false;
1225                                 }
1226                                 vfExec[nExecCount - 1] = !vfExec[nExecCount - 1];
1227                             }
1228                             break;
1229
1230                         case instruction.OP_ENDIF:
1231                             {
1232                                 int nExecCount = vfExec.Count();
1233                                 if (nExecCount == 0)
1234                                 {
1235                                     return false;
1236                                 }
1237                                 vfExec.RemoveAt(nExecCount - 1);
1238                             }
1239                             break;
1240
1241                         case instruction.OP_VERIFY:
1242                             {
1243                                 // (true -- ) or
1244                                 // (false -- false) and return
1245                                 if (stack.Count() < 1)
1246                                 {
1247                                     return false;
1248                                 }
1249
1250                                 bool fValue = CastToBool(stacktop(ref stack, -1));
1251                                 if (fValue)
1252                                 {
1253                                     popstack(ref stack);
1254                                 }
1255                                 else
1256                                 {
1257                                     return false;
1258                                 }
1259                             }
1260                             break;
1261
1262                         case instruction.OP_RETURN:
1263                             {
1264                                 return false;
1265                             }
1266
1267                         //
1268                         // Stack ops
1269                         //
1270                         case instruction.OP_TOALTSTACK:
1271                             {
1272                                 if (stack.Count() < 1)
1273                                 {
1274                                     return false;
1275                                 }
1276                                 altStack.Add(stacktop(ref stack, -1));
1277                                 popstack(ref stack);
1278                             }
1279                             break;
1280
1281                         case instruction.OP_FROMALTSTACK:
1282                             {
1283                                 if (altStack.Count() < 1)
1284                                 {
1285                                     return false;
1286                                 }
1287                                 stack.Add(stacktop(ref stack, -1));
1288                                 popstack(ref altStack);
1289                             }
1290                             break;
1291
1292                         case instruction.OP_2DROP:
1293                             {
1294                                 // (x1 x2 -- )
1295                                 if (stack.Count() < 2)
1296                                 {
1297                                     return false;
1298                                 }
1299                                 popstack(ref stack);
1300                                 popstack(ref stack);
1301                             }
1302                             break;
1303
1304                         case instruction.OP_2DUP:
1305                             {
1306                                 // (x1 x2 -- x1 x2 x1 x2)
1307                                 if (stack.Count() < 2)
1308                                 {
1309                                     return false;
1310                                 }
1311                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1312                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1313                                 stack.Add(vch1);
1314                                 stack.Add(vch2);
1315                             }
1316                             break;
1317
1318                         case instruction.OP_3DUP:
1319                             {
1320                                 // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
1321                                 if (stack.Count() < 3)
1322                                 {
1323                                     return false;
1324                                 }
1325                                 IEnumerable<byte> vch1 = stacktop(ref stack, -3);
1326                                 IEnumerable<byte> vch2 = stacktop(ref stack, -2);
1327                                 IEnumerable<byte> vch3 = stacktop(ref stack, -1);
1328                                 stack.Add(vch1);
1329                                 stack.Add(vch2);
1330                                 stack.Add(vch3);
1331                             }
1332                             break;
1333
1334                         case instruction.OP_2OVER:
1335                             {
1336                                 // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
1337                                 if (stack.Count() < 4)
1338                                 {
1339                                     return false;
1340                                 }
1341                                 IEnumerable<byte> vch1 = stacktop(ref stack, -4);
1342                                 IEnumerable<byte> vch2 = stacktop(ref stack, -3);
1343                                 stack.Add(vch1);
1344                                 stack.Add(vch2);
1345                             }
1346                             break;
1347
1348                         case instruction.OP_2ROT:
1349                             {
1350                                 int nStackDepth = stack.Count();
1351                                 // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
1352                                 if (nStackDepth < 6)
1353                                 {
1354                                     return false;
1355                                 }
1356                                 IEnumerable<byte> vch1 = stacktop(ref stack, -6);
1357                                 IEnumerable<byte> vch2 = stacktop(ref stack, -5);
1358                                 stack.RemoveRange(nStackDepth - 6, 2);
1359                                 stack.Add(vch1);
1360                                 stack.Add(vch2);
1361                             }
1362                             break;
1363
1364                         case instruction.OP_2SWAP:
1365                             {
1366                                 // (x1 x2 x3 x4 -- x3 x4 x1 x2)
1367                                 int nStackDepth = stack.Count();
1368                                 if (nStackDepth < 4)
1369                                 {
1370                                     return false;
1371                                 }
1372                                 stack.Swap(nStackDepth - 4, nStackDepth - 2);
1373                                 stack.Swap(nStackDepth - 3, nStackDepth - 1);
1374                             }
1375                             break;
1376
1377                         case instruction.OP_IFDUP:
1378                             {
1379                                 // (x - 0 | x x)
1380                                 if (stack.Count() < 1)
1381                                 {
1382                                     return false;
1383                                 }
1384
1385                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1386
1387                                 if (CastToBool(vch))
1388                                 {
1389                                     stack.Add(vch);
1390                                 }
1391                             }
1392                             break;
1393
1394                         case instruction.OP_DEPTH:
1395                             {
1396                                 // -- stacksize
1397                                 BigInteger bn = new BigInteger((ushort)stack.Count());
1398                                 stack.Add(bn.ToByteArray());
1399                             }
1400                             break;
1401
1402                         case instruction.OP_DROP:
1403                             {
1404                                 // (x -- )
1405                                 if (stack.Count() < 1)
1406                                 {
1407                                     return false;
1408                                 }
1409
1410                                 popstack(ref stack);
1411                             }
1412                             break;
1413
1414                         case instruction.OP_DUP:
1415                             {
1416                                 // (x -- x x)
1417                                 if (stack.Count() < 1)
1418                                 {
1419                                     return false;
1420                                 }
1421
1422                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1423                                 stack.Add(vch);
1424                             }
1425                             break;
1426
1427                         case instruction.OP_NIP:
1428                             {
1429                                 // (x1 x2 -- x2)
1430                                 int nStackDepth = stack.Count();
1431                                 if (nStackDepth < 2)
1432                                 {
1433                                     return false;
1434                                 }
1435
1436                                 stack.RemoveAt(nStackDepth - 2);
1437                             }
1438                             break;
1439
1440                         case instruction.OP_OVER:
1441                             {
1442                                 // (x1 x2 -- x1 x2 x1)
1443                                 if (stack.Count() < 2)
1444                                 {
1445                                     return false;
1446                                 }
1447
1448                                 IEnumerable<byte> vch = stacktop(ref stack, -2);
1449                                 stack.Add(vch);
1450                             }
1451                             break;
1452
1453                         case instruction.OP_PICK:
1454                         case instruction.OP_ROLL:
1455                             {
1456                                 // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
1457                                 // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
1458
1459                                 int nStackDepth = stack.Count();
1460                                 if (nStackDepth < 2)
1461                                 {
1462                                     return false;
1463                                 }
1464
1465                                 int n = (int)CastToBigInteger(stacktop(ref stack, -1));
1466                                 popstack(ref stack);
1467
1468                                 if (n < 0 || n >= stack.Count())
1469                                 {
1470                                     return false;
1471                                 }
1472
1473                                 IEnumerable<byte> vch = stacktop(ref stack, -n - 1);
1474                                 if (opcode == instruction.OP_ROLL)
1475                                 {
1476                                     stack.RemoveAt(nStackDepth - n - 1);
1477                                 }
1478
1479                                 stack.Add(vch);
1480                             }
1481                             break;
1482
1483                         case instruction.OP_ROT:
1484                             {
1485                                 // (x1 x2 x3 -- x2 x3 x1)
1486                                 //  x2 x1 x3  after first swap
1487                                 //  x2 x3 x1  after second swap
1488                                 int nStackDepth = stack.Count();
1489                                 if (nStackDepth < 3)
1490                                 {
1491                                     return false;
1492                                 }
1493                                 stack.Swap(nStackDepth - 3, nStackDepth - 2);
1494                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1495
1496                             }
1497                             break;
1498
1499                         case instruction.OP_SWAP:
1500                             {
1501                                 // (x1 x2 -- x2 x1)
1502                                 int nStackDepth = stack.Count();
1503                                 if (nStackDepth < 2)
1504                                 {
1505                                     return false;
1506                                 }
1507                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1508                             }
1509                             break;
1510
1511                         case instruction.OP_TUCK:
1512                             {
1513                                 // (x1 x2 -- x2 x1 x2)
1514                                 int nStackDepth = stack.Count();
1515                                 if (nStackDepth < 2)
1516                                 {
1517                                     return false;
1518                                 }
1519                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1520                                 stack.Insert(nStackDepth - 2, vch);
1521                             }
1522                             break;
1523
1524
1525                         case instruction.OP_SIZE:
1526                             {
1527                                 // (in -- in size)
1528                                 if (stack.Count() < 1)
1529                                 {
1530                                     return false;
1531                                 }
1532
1533                                 BigInteger bnSize = new BigInteger((ushort)stacktop(ref stack, -1).Count());
1534                                 stack.Add(bnSize.ToByteArray());
1535                             }
1536                             break;
1537
1538
1539                         //
1540                         // Bitwise logic
1541                         //
1542                         case instruction.OP_EQUAL:
1543                         case instruction.OP_EQUALVERIFY:
1544                             //case instruction.OP_NOTEQUAL: // use OP_NUMNOTEQUAL
1545                             {
1546                                 // (x1 x2 - bool)
1547                                 if (stack.Count() < 2)
1548                                 {
1549                                     return false;
1550                                 }
1551
1552                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1553                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1554                                 bool fEqual = (vch1 == vch2);
1555                                 // OP_NOTEQUAL is disabled because it would be too easy to say
1556                                 // something like n != 1 and have some wiseguy pass in 1 with extra
1557                                 // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
1558                                 //if (opcode == instruction.OP_NOTEQUAL)
1559                                 //    fEqual = !fEqual;
1560                                 popstack(ref stack);
1561                                 popstack(ref stack);
1562                                 stack.Add(fEqual ? trueBytes : falseBytes);
1563
1564                                 if (opcode == instruction.OP_EQUALVERIFY)
1565                                 {
1566                                     if (fEqual)
1567                                     {
1568                                         popstack(ref stack);
1569                                     }
1570                                     else
1571                                     {
1572                                         return false;
1573                                     }
1574                                 }
1575                             }
1576                             break;
1577
1578
1579                         //
1580                         // Numeric
1581                         //
1582                         case instruction.OP_1ADD:
1583                         case instruction.OP_1SUB:
1584                         case instruction.OP_NEGATE:
1585                         case instruction.OP_ABS:
1586                         case instruction.OP_NOT:
1587                         case instruction.OP_0NOTEQUAL:
1588                             {
1589                                 // (in -- out)
1590                                 if (stack.Count() < 1)
1591                                 {
1592                                     return false;
1593                                 }
1594
1595                                 BigInteger bn = CastToBigInteger(stacktop(ref stack, -1));
1596                                 switch (opcode)
1597                                 {
1598                                     case instruction.OP_1ADD:
1599                                         bn = bn + 1;
1600                                         break;
1601                                     case instruction.OP_1SUB:
1602                                         bn = bn - 1;
1603                                         break;
1604                                     case instruction.OP_NEGATE:
1605                                         bn = -bn;
1606                                         break;
1607                                     case instruction.OP_ABS:
1608                                         bn = BigInteger.Abs(bn);
1609                                         break;
1610                                     case instruction.OP_NOT:
1611                                         bn = bn == 0 ? 1 : 0;
1612                                         break;
1613                                     case instruction.OP_0NOTEQUAL:
1614                                         bn = bn != 0 ? 1 : 0;
1615                                         break;
1616
1617                                     default:
1618                                         throw new StackMachineException("invalid instruction");
1619                                 }
1620
1621                                 popstack(ref stack);
1622                                 stack.Add(bn.ToByteArray());
1623                             }
1624                             break;
1625
1626                         case instruction.OP_ADD:
1627                         case instruction.OP_SUB:
1628                         case instruction.OP_BOOLAND:
1629                         case instruction.OP_BOOLOR:
1630                         case instruction.OP_NUMEQUAL:
1631                         case instruction.OP_NUMEQUALVERIFY:
1632                         case instruction.OP_NUMNOTEQUAL:
1633                         case instruction.OP_LESSTHAN:
1634                         case instruction.OP_GREATERTHAN:
1635                         case instruction.OP_LESSTHANOREQUAL:
1636                         case instruction.OP_GREATERTHANOREQUAL:
1637                         case instruction.OP_MIN:
1638                         case instruction.OP_MAX:
1639                             {
1640                                 // (x1 x2 -- out)
1641                                 if (stack.Count() < 2)
1642                                 {
1643                                     return false;
1644                                 }
1645
1646                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -2));
1647                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -1));
1648                                 BigInteger bn = 0;
1649
1650                                 switch (opcode)
1651                                 {
1652                                     case instruction.OP_ADD:
1653                                         bn = bn1 + bn2;
1654                                         break;
1655                                     case instruction.OP_SUB:
1656                                         bn = bn1 - bn2;
1657                                         break;
1658                                     case instruction.OP_BOOLAND:
1659                                         bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1660                                         break;
1661                                     case instruction.OP_BOOLOR:
1662                                         bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1663                                         break;
1664                                     case instruction.OP_NUMEQUAL:
1665                                         bn = (bn1 == bn2) ? 1 : 0;
1666                                         break;
1667                                     case instruction.OP_NUMEQUALVERIFY:
1668                                         bn = (bn1 == bn2) ? 1 : 0;
1669                                         break;
1670                                     case instruction.OP_NUMNOTEQUAL:
1671                                         bn = (bn1 != bn2) ? 1 : 0;
1672                                         break;
1673                                     case instruction.OP_LESSTHAN:
1674                                         bn = (bn1 < bn2) ? 1 : 0;
1675                                         break;
1676                                     case instruction.OP_GREATERTHAN:
1677                                         bn = (bn1 > bn2) ? 1 : 0;
1678                                         break;
1679                                     case instruction.OP_LESSTHANOREQUAL:
1680                                         bn = (bn1 <= bn2) ? 1 : 0;
1681                                         break;
1682                                     case instruction.OP_GREATERTHANOREQUAL:
1683                                         bn = (bn1 >= bn2) ? 1 : 0;
1684                                         break;
1685                                     case instruction.OP_MIN:
1686                                         bn = (bn1 < bn2 ? bn1 : bn2);
1687                                         break;
1688                                     case instruction.OP_MAX:
1689                                         bn = (bn1 > bn2 ? bn1 : bn2);
1690                                         break;
1691
1692                                     default:
1693                                         throw new StackMachineException("invalid instruction");
1694                                 }
1695
1696                                 popstack(ref stack);
1697                                 popstack(ref stack);
1698                                 stack.Add(bn.ToByteArray());
1699
1700                                 if (opcode == instruction.OP_NUMEQUALVERIFY)
1701                                 {
1702                                     if (CastToBool(stacktop(ref stack, -1)))
1703                                     {
1704                                         popstack(ref stack);
1705                                     }
1706                                     else
1707                                     {
1708                                         return false;
1709                                     }
1710                                 }
1711                             }
1712                             break;
1713
1714                         case instruction.OP_WITHIN:
1715                             {
1716                                 // (x min max -- out)
1717                                 if (stack.Count() < 3)
1718                                     return false;
1719                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -3));
1720                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -2));
1721                                 BigInteger bn3 = CastToBigInteger(stacktop(ref stack, -1));
1722                                 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1723                                 popstack(ref stack);
1724                                 popstack(ref stack);
1725                                 popstack(ref stack);
1726                                 stack.Add(fValue ? trueBytes : falseBytes);
1727                             }
1728                             break;
1729
1730
1731                         //
1732                         // Crypto
1733                         //
1734                         case instruction.OP_RIPEMD160:
1735                         case instruction.OP_SHA1:
1736                         case instruction.OP_SHA256:
1737                         case instruction.OP_HASH160:
1738                         case instruction.OP_HASH256:
1739                             {
1740                                 // (in -- hash)
1741                                 if (stack.Count() < 1)
1742                                     return false;
1743                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1744                                 IEnumerable<byte> vchHash = null;
1745                                 if (opcode == instruction.OP_RIPEMD160)
1746                                 {
1747                                     RIPEMD160 hash = RIPEMD160.Compute160(vch);
1748                                     vchHash = hash.hashBytes;
1749                                 }
1750                                 else if (opcode == instruction.OP_SHA1)
1751                                 {
1752                                     SHA1 hash = SHA1.Compute1(vch);
1753                                     vchHash = hash.hashBytes;
1754                                 }
1755                                 else if (opcode == instruction.OP_SHA256)
1756                                 {
1757                                     SHA256 hash = SHA256.Compute256(vch);
1758                                     vchHash = hash.hashBytes;
1759                                 }
1760                                 else if (opcode == instruction.OP_HASH160)
1761                                 {
1762                                     Hash160 hash = Hash160.Compute160(vch);
1763                                     vchHash = hash.hashBytes;
1764                                 }
1765                                 else if (opcode == instruction.OP_HASH256)
1766                                 {
1767                                     Hash256 hash = Hash256.Compute256(vch);
1768                                     vchHash = hash.hashBytes;
1769                                 }
1770                                 popstack(ref stack);
1771                                 stack.Add(vchHash);
1772                             }
1773                             break;
1774
1775                         case instruction.OP_CODESEPARATOR:
1776                             {
1777                                 // Hash starts after the code separator
1778                                 nCodeHashBegin = CodeQueue.CurrentIndex;
1779                             }
1780                             break;
1781
1782                         case instruction.OP_CHECKSIG:
1783                         case instruction.OP_CHECKSIGVERIFY:
1784                             {
1785                                 // (sig pubkey -- bool)
1786                                 if (stack.Count() < 2)
1787                                 {
1788                                     return false;
1789                                 }
1790
1791                                 IList<byte> sigBytes = stacktop(ref stack, -2).ToList();
1792                                 IList<byte> pubkeyBytes = stacktop(ref stack, -1).ToList();
1793
1794                                 // Subset of script starting at the most recent codeseparator
1795                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1796
1797                                 // There's no way for a signature to sign itself
1798                                 scriptCode.RemovePattern(sigBytes);
1799
1800                                 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes.ToList(), flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1801
1802                                 popstack(ref stack);
1803                                 popstack(ref stack);
1804                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1805                                 if (opcode == instruction.OP_CHECKSIGVERIFY)
1806                                 {
1807                                     if (fSuccess)
1808                                     {
1809                                         popstack(ref stack);
1810                                     }
1811                                     else
1812                                     {
1813                                         return false;
1814                                     }
1815                                 }
1816                             }
1817                             break;
1818
1819                         case instruction.OP_CHECKMULTISIG:
1820                         case instruction.OP_CHECKMULTISIGVERIFY:
1821                             {
1822                                 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1823
1824                                 int i = 1;
1825                                 if (stack.Count() < i)
1826                                 {
1827                                     return false;
1828                                 }
1829
1830                                 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1831                                 if (nKeysCount < 0 || nKeysCount > 20)
1832                                 {
1833                                     return false;
1834                                 }
1835                                 nOpCount += nKeysCount;
1836                                 if (nOpCount > 201)
1837                                 {
1838                                     return false;
1839                                 }
1840                                 int ikey = ++i;
1841                                 i += nKeysCount;
1842                                 if (stack.Count() < i)
1843                                 {
1844                                     return false;
1845                                 }
1846
1847                                 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1848                                 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1849                                 {
1850                                     return false;
1851                                 }
1852                                 int isig = ++i;
1853                                 i += nSigsCount;
1854                                 if (stack.Count() < i)
1855                                 {
1856                                     return false;
1857                                 }
1858
1859                                 // Subset of script starting at the most recent codeseparator
1860                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1861
1862                                 // There is no way for a signature to sign itself, so we need to drop the signatures
1863                                 for (int k = 0; k < nSigsCount; k++)
1864                                 {
1865                                     IEnumerable<byte> vchSig = stacktop(ref stack, -isig - k);
1866                                     scriptCode.RemovePattern(vchSig.ToList());
1867                                 }
1868
1869                                 bool fSuccess = true;
1870                                 while (fSuccess && nSigsCount > 0)
1871                                 {
1872                                     IList<byte> sigBytes = stacktop(ref stack, -isig).ToList();
1873                                     IList<byte> pubKeyBytes = stacktop(ref stack, -ikey).ToList();
1874
1875                                     // Check signature
1876                                     bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes.ToList(), flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1877
1878                                     if (fOk)
1879                                     {
1880                                         isig++;
1881                                         nSigsCount--;
1882                                     }
1883                                     ikey++;
1884                                     nKeysCount--;
1885
1886                                     // If there are more signatures left than keys left,
1887                                     // then too many signatures have failed
1888                                     if (nSigsCount > nKeysCount)
1889                                     {
1890                                         fSuccess = false;
1891                                     }
1892                                 }
1893
1894                                 while (i-- > 1)
1895                                 {
1896                                     popstack(ref stack);
1897                                 }
1898
1899                                 // A bug causes CHECKMULTISIG to consume one extra argument
1900                                 // whose contents were not checked in any way.
1901                                 //
1902                                 // Unfortunately this is a potential source of mutability,
1903                                 // so optionally verify it is exactly equal to zero prior
1904                                 // to removing it from the stack.
1905                                 if (stack.Count() < 1)
1906                                 {
1907                                     return false;
1908                                 }
1909                                 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1910                                 {
1911                                     return false; // CHECKMULTISIG dummy argument not null
1912                                 }
1913                                 popstack(ref stack);
1914
1915                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1916
1917                                 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1918                                 {
1919                                     if (fSuccess)
1920                                     {
1921                                         popstack(ref stack);
1922                                     }
1923                                     else
1924                                     {
1925                                         return false;
1926                                     }
1927                                 }
1928                             }
1929                             break;
1930
1931                         default:
1932                             return false;
1933                     }
1934
1935                 // Size limits
1936                 if (stack.Count() + altStack.Count() > 1000)
1937                 {
1938                     return false;
1939                 }
1940             }
1941
1942
1943             if (vfExec.Count() == 0)
1944             {
1945                 return false;
1946             }
1947
1948             return true;
1949         }
1950
1951
1952         static bool IsCanonicalPubKey(IList<byte> pubKeyBytes, int flags)
1953         {
1954             if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1955                 return true;
1956
1957             if (pubKeyBytes.Count < 33)
1958                 return false;  // Non-canonical public key: too short
1959             if (pubKeyBytes[0] == 0x04)
1960             {
1961                 if (pubKeyBytes.Count != 65)
1962                     return false; // Non-canonical public key: invalid length for uncompressed key
1963             }
1964             else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1965             {
1966                 if (pubKeyBytes.Count != 33)
1967                     return false; // Non-canonical public key: invalid length for compressed key
1968             }
1969             else
1970             {
1971                 return false; // Non-canonical public key: compressed nor uncompressed
1972             }
1973             return true;
1974         }
1975
1976         static bool IsCanonicalSignature(IList<byte> sigBytes, int flags)
1977         {
1978             // STUB
1979
1980             return true;
1981         }
1982
1983         static bool CheckSig(IList<byte> vchSig, IList<byte> vchPubKey, CScript scriptCode, CTransaction txTo, int nIn, int nHashType, int flags)
1984         {
1985             CPubKey pubkey;
1986
1987             try
1988             {
1989                 // Trying to initialize the public key instance
1990
1991                 pubkey = new CPubKey(vchPubKey);
1992             }
1993             catch (Exception)
1994             {
1995                 // Exception occurred while initializing the public key
1996
1997                 return false;
1998             }
1999
2000             if (!pubkey.IsValid)
2001             {
2002                 return false;
2003             }
2004
2005             if (vchSig.Count == 0)
2006             {
2007                 return false;
2008             }
2009
2010             // Hash type is one byte tacked on to the end of the signature
2011             if (nHashType == 0)
2012             {
2013                 nHashType = vchSig.Last();
2014             }
2015             else if (nHashType != vchSig.Last())
2016             {
2017                 return false;
2018             }
2019
2020             // Remove hash type
2021             vchSig.RemoveAt(vchSig.Count - 1);
2022
2023             Hash256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
2024
2025             if (!pubkey.VerifySignature(sighash, vchSig))
2026             {
2027                 return false;
2028             }
2029
2030             return true;
2031         }
2032     };
2033 }