Novacoin/ScriptCode.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Text;
   5
   6 using System.Numerics;
   7
   8 // using Org.BouncyCastle.Math;
   9
  10 namespace Novacoin
  11 {
  12     /// <summary>
  13     /// Script opcodes
  14     /// </summary>
  15     public enum instruction
  16     {
  17         // push value
  18         OP_0 = 0x00,
  19         OP_FALSE = OP_0,
  20         OP_PUSHDATA1 = 0x4c,
  21         OP_PUSHDATA2 = 0x4d,
  22         OP_PUSHDATA4 = 0x4e,
  23         OP_1NEGATE = 0x4f,
  24         OP_RESERVED = 0x50,
  25         OP_1 = 0x51,
  26         OP_TRUE = OP_1,
  27         OP_2 = 0x52,
  28         OP_3 = 0x53,
  29         OP_4 = 0x54,
  30         OP_5 = 0x55,
  31         OP_6 = 0x56,
  32         OP_7 = 0x57,
  33         OP_8 = 0x58,
  34         OP_9 = 0x59,
  35         OP_10 = 0x5a,
  36         OP_11 = 0x5b,
  37         OP_12 = 0x5c,
  38         OP_13 = 0x5d,
  39         OP_14 = 0x5e,
  40         OP_15 = 0x5f,
  41         OP_16 = 0x60,
  42
  43         // control
  44         OP_NOP = 0x61,
  45         OP_VER = 0x62,
  46         OP_IF = 0x63,
  47         OP_NOTIF = 0x64,
  48         OP_VERIF = 0x65,
  49         OP_VERNOTIF = 0x66,
  50         OP_ELSE = 0x67,
  51         OP_ENDIF = 0x68,
  52         OP_VERIFY = 0x69,
  53         OP_RETURN = 0x6a,
  54
  55         // stack ops
  56         OP_TOALTSTACK = 0x6b,
  57         OP_FROMALTSTACK = 0x6c,
  58         OP_2DROP = 0x6d,
  59         OP_2DUP = 0x6e,
  60         OP_3DUP = 0x6f,
  61         OP_2OVER = 0x70,
  62         OP_2ROT = 0x71,
  63         OP_2SWAP = 0x72,
  64         OP_IFDUP = 0x73,
  65         OP_DEPTH = 0x74,
  66         OP_DROP = 0x75,
  67         OP_DUP = 0x76,
  68         OP_NIP = 0x77,
  69         OP_OVER = 0x78,
  70         OP_PICK = 0x79,
  71         OP_ROLL = 0x7a,
  72         OP_ROT = 0x7b,
  73         OP_SWAP = 0x7c,
  74         OP_TUCK = 0x7d,
  75
  76         // splice ops
  77         OP_CAT = 0x7e,
  78         OP_SUBSTR = 0x7f,
  79         OP_LEFT = 0x80,
  80         OP_RIGHT = 0x81,
  81         OP_SIZE = 0x82,
  82
  83         // bit logic
  84         OP_INVERT = 0x83,
  85         OP_AND = 0x84,
  86         OP_OR = 0x85,
  87         OP_XOR = 0x86,
  88         OP_EQUAL = 0x87,
  89         OP_EQUALVERIFY = 0x88,
  90         OP_RESERVED1 = 0x89,
  91         OP_RESERVED2 = 0x8a,
  92
  93         // numeric
  94         OP_1ADD = 0x8b,
  95         OP_1SUB = 0x8c,
  96         OP_2MUL = 0x8d,
  97         OP_2DIV = 0x8e,
  98         OP_NEGATE = 0x8f,
  99         OP_ABS = 0x90,
 100         OP_NOT = 0x91,
 101         OP_0NOTEQUAL = 0x92,
 102
 103         OP_ADD = 0x93,
 104         OP_SUB = 0x94,
 105         OP_MUL = 0x95,
 106         OP_DIV = 0x96,
 107         OP_MOD = 0x97,
 108         OP_LSHIFT = 0x98,
 109         OP_RSHIFT = 0x99,
 110
 111         OP_BOOLAND = 0x9a,
 112         OP_BOOLOR = 0x9b,
 113         OP_NUMEQUAL = 0x9c,
 114         OP_NUMEQUALVERIFY = 0x9d,
 115         OP_NUMNOTEQUAL = 0x9e,
 116         OP_LESSTHAN = 0x9f,
 117         OP_GREATERTHAN = 0xa0,
 118         OP_LESSTHANOREQUAL = 0xa1,
 119         OP_GREATERTHANOREQUAL = 0xa2,
 120         OP_MIN = 0xa3,
 121         OP_MAX = 0xa4,
 122
 123         OP_WITHIN = 0xa5,
 124
 125         // crypto
 126         OP_RIPEMD160 = 0xa6,
 127         OP_SHA1 = 0xa7,
 128         OP_SHA256 = 0xa8,
 129         OP_HASH160 = 0xa9,
 130         OP_HASH256 = 0xaa,
 131         OP_CODESEPARATOR = 0xab,
 132         OP_CHECKSIG = 0xac,
 133         OP_CHECKSIGVERIFY = 0xad,
 134         OP_CHECKMULTISIG = 0xae,
 135         OP_CHECKMULTISIGVERIFY = 0xaf,
 136
 137         // expansion
 138         OP_NOP1 = 0xb0,
 139         OP_NOP2 = 0xb1,
 140         OP_NOP3 = 0xb2,
 141         OP_NOP4 = 0xb3,
 142         OP_NOP5 = 0xb4,
 143         OP_NOP6 = 0xb5,
 144         OP_NOP7 = 0xb6,
 145         OP_NOP8 = 0xb7,
 146         OP_NOP9 = 0xb8,
 147         OP_NOP10 = 0xb9,
 148
 149         // template matching params
 150         OP_SMALLDATA = 0xf9,
 151         OP_SMALLINTEGER = 0xfa,
 152         OP_PUBKEYS = 0xfb,
 153         OP_PUBKEYHASH = 0xfd,
 154         OP_PUBKEY = 0xfe,
 155
 156         OP_INVALIDOPCODE = 0xff,
 157     };
 158
 159     /// <summary>
 160     /// Transaction output types.
 161     /// </summary>
 162     public enum txnouttype
 163     {
 164         TX_NONSTANDARD,
 165
 166         // 'standard' transaction types:
 167         TX_PUBKEY,
 168         TX_PUBKEYHASH,
 169         TX_SCRIPTHASH,
 170         TX_MULTISIG,
 171         TX_NULL_DATA,
 172     };
 173
 174     /// <summary>
 175     /// Signature hash types/flags
 176     /// </summary>
 177     public enum sigflag
 178     {
 179         SIGHASH_ALL = 1,
 180         SIGHASH_NONE = 2,
 181         SIGHASH_SINGLE = 3,
 182         SIGHASH_ANYONECANPAY = 0x80,
 183     };
 184
 185     /** Script verification flags */
 186     public enum scriptflag
 187     {
 188         SCRIPT_VERIFY_NONE = 0,
 189         SCRIPT_VERIFY_P2SH = (1 << 0), // evaluate P2SH (BIP16) subscripts
 190         SCRIPT_VERIFY_STRICTENC = (1 << 1), // enforce strict conformance to DER and SEC2 for signatures and pubkeys
 191         SCRIPT_VERIFY_LOW_S = (1 << 2), // enforce low S values in signatures (depends on STRICTENC)
 192         SCRIPT_VERIFY_NOCACHE = (1 << 3), // do not store results in signature cache (but do query it)
 193         SCRIPT_VERIFY_NULLDUMMY = (1 << 4), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
 194     };
 195
 196     public static class ScriptCode
 197     {
 198         public static string GetTxnOutputType(txnouttype t)
 199         {
 200             switch (t)
 201             {
 202                 case txnouttype.TX_NONSTANDARD: return "nonstandard";
 203                 case txnouttype.TX_PUBKEY: return "pubkey";
 204                 case txnouttype.TX_PUBKEYHASH: return "pubkeyhash";
 205                 case txnouttype.TX_SCRIPTHASH: return "scripthash";
 206                 case txnouttype.TX_MULTISIG: return "multisig";
 207                 case txnouttype.TX_NULL_DATA: return "nulldata";
 208             }
 209             return string.Empty;
 210         }
 211
 212         /// <summary>
 213         /// Get the name of supplied opcode
 214         /// </summary>
 215         /// <param name="opcode">Opcode</param>
 216         /// <returns>Opcode name</returns>
 217         public static string GetOpName(instruction opcode)
 218         {
 219             switch (opcode)
 220             {
 221                 // push value
 222                 case instruction.OP_0:
 223                     return "OP_0";
 224                 case instruction.OP_PUSHDATA1:
 225                     return "OP_PUSHDATA1";
 226                 case instruction.OP_PUSHDATA2:
 227                     return "OP_PUSHDATA2";
 228                 case instruction.OP_PUSHDATA4:
 229                     return "OP_PUSHDATA4";
 230                 case instruction.OP_1NEGATE:
 231                     return "OP_1NEGATE";
 232                 case instruction.OP_RESERVED:
 233                     return "OP_RESERVED";
 234                 case instruction.OP_1:
 235                     return "OP_1";
 236                 case instruction.OP_2:
 237                     return "OP_2";
 238                 case instruction.OP_3:
 239                     return "OP_3";
 240                 case instruction.OP_4:
 241                     return "OP_4";
 242                 case instruction.OP_5:
 243                     return "OP_5";
 244                 case instruction.OP_6:
 245                     return "OP_6";
 246                 case instruction.OP_7:
 247                     return "OP_7";
 248                 case instruction.OP_8:
 249                     return "OP_8";
 250                 case instruction.OP_9:
 251                     return "OP_9";
 252                 case instruction.OP_10:
 253                     return "OP_10";
 254                 case instruction.OP_11:
 255                     return "OP_11";
 256                 case instruction.OP_12:
 257                     return "OP_12";
 258                 case instruction.OP_13:
 259                     return "OP_13";
 260                 case instruction.OP_14:
 261                     return "OP_14";
 262                 case instruction.OP_15:
 263                     return "OP_15";
 264                 case instruction.OP_16:
 265                     return "OP_16";
 266
 267                 // control
 268                 case instruction.OP_NOP:
 269                     return "OP_NOP";
 270                 case instruction.OP_VER:
 271                     return "OP_VER";
 272                 case instruction.OP_IF:
 273                     return "OP_IF";
 274                 case instruction.OP_NOTIF:
 275                     return "OP_NOTIF";
 276                 case instruction.OP_VERIF:
 277                     return "OP_VERIF";
 278                 case instruction.OP_VERNOTIF:
 279                     return "OP_VERNOTIF";
 280                 case instruction.OP_ELSE:
 281                     return "OP_ELSE";
 282                 case instruction.OP_ENDIF:
 283                     return "OP_ENDIF";
 284                 case instruction.OP_VERIFY:
 285                     return "OP_VERIFY";
 286                 case instruction.OP_RETURN:
 287                     return "OP_RETURN";
 288
 289                 // stack ops
 290                 case instruction.OP_TOALTSTACK:
 291                     return "OP_TOALTSTACK";
 292                 case instruction.OP_FROMALTSTACK:
 293                     return "OP_FROMALTSTACK";
 294                 case instruction.OP_2DROP:
 295                     return "OP_2DROP";
 296                 case instruction.OP_2DUP:
 297                     return "OP_2DUP";
 298                 case instruction.OP_3DUP:
 299                     return "OP_3DUP";
 300                 case instruction.OP_2OVER:
 301                     return "OP_2OVER";
 302                 case instruction.OP_2ROT:
 303                     return "OP_2ROT";
 304                 case instruction.OP_2SWAP:
 305                     return "OP_2SWAP";
 306                 case instruction.OP_IFDUP:
 307                     return "OP_IFDUP";
 308                 case instruction.OP_DEPTH:
 309                     return "OP_DEPTH";
 310                 case instruction.OP_DROP:
 311                     return "OP_DROP";
 312                 case instruction.OP_DUP:
 313                     return "OP_DUP";
 314                 case instruction.OP_NIP:
 315                     return "OP_NIP";
 316                 case instruction.OP_OVER:
 317                     return "OP_OVER";
 318                 case instruction.OP_PICK:
 319                     return "OP_PICK";
 320                 case instruction.OP_ROLL:
 321                     return "OP_ROLL";
 322                 case instruction.OP_ROT:
 323                     return "OP_ROT";
 324                 case instruction.OP_SWAP:
 325                     return "OP_SWAP";
 326                 case instruction.OP_TUCK:
 327                     return "OP_TUCK";
 328
 329                 // splice ops
 330                 case instruction.OP_CAT:
 331                     return "OP_CAT";
 332                 case instruction.OP_SUBSTR:
 333                     return "OP_SUBSTR";
 334                 case instruction.OP_LEFT:
 335                     return "OP_LEFT";
 336                 case instruction.OP_RIGHT:
 337                     return "OP_RIGHT";
 338                 case instruction.OP_SIZE:
 339                     return "OP_SIZE";
 340
 341                 // bit logic
 342                 case instruction.OP_INVERT:
 343                     return "OP_INVERT";
 344                 case instruction.OP_AND:
 345                     return "OP_AND";
 346                 case instruction.OP_OR:
 347                     return "OP_OR";
 348                 case instruction.OP_XOR:
 349                     return "OP_XOR";
 350                 case instruction.OP_EQUAL:
 351                     return "OP_EQUAL";
 352                 case instruction.OP_EQUALVERIFY:
 353                     return "OP_EQUALVERIFY";
 354                 case instruction.OP_RESERVED1:
 355                     return "OP_RESERVED1";
 356                 case instruction.OP_RESERVED2:
 357                     return "OP_RESERVED2";
 358
 359                 // numeric
 360                 case instruction.OP_1ADD:
 361                     return "OP_1ADD";
 362                 case instruction.OP_1SUB:
 363                     return "OP_1SUB";
 364                 case instruction.OP_2MUL:
 365                     return "OP_2MUL";
 366                 case instruction.OP_2DIV:
 367                     return "OP_2DIV";
 368                 case instruction.OP_NEGATE:
 369                     return "OP_NEGATE";
 370                 case instruction.OP_ABS:
 371                     return "OP_ABS";
 372                 case instruction.OP_NOT:
 373                     return "OP_NOT";
 374                 case instruction.OP_0NOTEQUAL:
 375                     return "OP_0NOTEQUAL";
 376                 case instruction.OP_ADD:
 377                     return "OP_ADD";
 378                 case instruction.OP_SUB:
 379                     return "OP_SUB";
 380                 case instruction.OP_MUL:
 381                     return "OP_MUL";
 382                 case instruction.OP_DIV:
 383                     return "OP_DIV";
 384                 case instruction.OP_MOD:
 385                     return "OP_MOD";
 386                 case instruction.OP_LSHIFT:
 387                     return "OP_LSHIFT";
 388                 case instruction.OP_RSHIFT:
 389                     return "OP_RSHIFT";
 390                 case instruction.OP_BOOLAND:
 391                     return "OP_BOOLAND";
 392                 case instruction.OP_BOOLOR:
 393                     return "OP_BOOLOR";
 394                 case instruction.OP_NUMEQUAL:
 395                     return "OP_NUMEQUAL";
 396                 case instruction.OP_NUMEQUALVERIFY:
 397                     return "OP_NUMEQUALVERIFY";
 398                 case instruction.OP_NUMNOTEQUAL:
 399                     return "OP_NUMNOTEQUAL";
 400                 case instruction.OP_LESSTHAN:
 401                     return "OP_LESSTHAN";
 402                 case instruction.OP_GREATERTHAN:
 403                     return "OP_GREATERTHAN";
 404                 case instruction.OP_LESSTHANOREQUAL:
 405                     return "OP_LESSTHANOREQUAL";
 406                 case instruction.OP_GREATERTHANOREQUAL:
 407                     return "OP_GREATERTHANOREQUAL";
 408                 case instruction.OP_MIN:
 409                     return "OP_MIN";
 410                 case instruction.OP_MAX:
 411                     return "OP_MAX";
 412                 case instruction.OP_WITHIN:
 413                     return "OP_WITHIN";
 414
 415                 // crypto
 416                 case instruction.OP_RIPEMD160:
 417                     return "OP_RIPEMD160";
 418                 case instruction.OP_SHA1:
 419                     return "OP_SHA1";
 420                 case instruction.OP_SHA256:
 421                     return "OP_SHA256";
 422                 case instruction.OP_HASH160:
 423                     return "OP_HASH160";
 424                 case instruction.OP_HASH256:
 425                     return "OP_HASH256";
 426                 case instruction.OP_CODESEPARATOR:
 427                     return "OP_CODESEPARATOR";
 428                 case instruction.OP_CHECKSIG:
 429                     return "OP_CHECKSIG";
 430                 case instruction.OP_CHECKSIGVERIFY:
 431                     return "OP_CHECKSIGVERIFY";
 432                 case instruction.OP_CHECKMULTISIG:
 433                     return "OP_CHECKMULTISIG";
 434                 case instruction.OP_CHECKMULTISIGVERIFY:
 435                     return "OP_CHECKMULTISIGVERIFY";
 436
 437                 // expansion
 438                 case instruction.OP_NOP1:
 439                     return "OP_NOP1";
 440                 case instruction.OP_NOP2:
 441                     return "OP_NOP2";
 442                 case instruction.OP_NOP3:
 443                     return "OP_NOP3";
 444                 case instruction.OP_NOP4:
 445                     return "OP_NOP4";
 446                 case instruction.OP_NOP5:
 447                     return "OP_NOP5";
 448                 case instruction.OP_NOP6:
 449                     return "OP_NOP6";
 450                 case instruction.OP_NOP7:
 451                     return "OP_NOP7";
 452                 case instruction.OP_NOP8:
 453                     return "OP_NOP8";
 454                 case instruction.OP_NOP9:
 455                     return "OP_NOP9";
 456                 case instruction.OP_NOP10:
 457                     return "OP_NOP10";
 458
 459                 // template matching params
 460                 case instruction.OP_PUBKEYHASH:
 461                     return "OP_PUBKEYHASH";
 462                 case instruction.OP_PUBKEY:
 463                     return "OP_PUBKEY";
 464                 case instruction.OP_SMALLDATA:
 465                     return "OP_SMALLDATA";
 466
 467                 case instruction.OP_INVALIDOPCODE:
 468                     return "OP_INVALIDOPCODE";
 469                 default:
 470                     return "OP_UNKNOWN";
 471             }
 472         }
 473
 474         /// <summary>
 475         /// Get next opcode from passed list of bytes and extract push arguments if there are some.
 476         /// </summary>
 477         /// <param name="codeBytes">ByteQueue reference.</param>
 478         /// <param name="opcodeRet">Found opcode.</param>
 479         /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
 480         /// <returns>Result of operation</returns>
 481         public static bool GetOp(ref ByteQueue codeBytes, out instruction opcodeRet, out IEnumerable<byte> bytesRet)
 482         {
 483             bytesRet = new List<byte>();
 484             opcodeRet = instruction.OP_INVALIDOPCODE;
 485
 486             instruction opcode;
 487
 488             try
 489             {
 490                 // Read instruction
 491                 opcode = (instruction)codeBytes.Get();
 492             }
 493             catch (ByteQueueException)
 494             {
 495                 // No instruction found there
 496                 return false;
 497             }
 498
 499             // Immediate operand
 500             if (opcode <= instruction.OP_PUSHDATA4)
 501             {
 502                 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
 503
 504                 try
 505                 {
 506                     if (opcode < instruction.OP_PUSHDATA1)
 507                     {
 508                         // Zero value opcodes (OP_0, OP_FALSE)
 509                         szBytes[3] = (byte)opcode;
 510                     }
 511                     else if (opcode == instruction.OP_PUSHDATA1)
 512                     {
 513                         // The next byte contains the number of bytes to be pushed onto the stack,
 514                         //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
 515                         szBytes[3] = (byte)codeBytes.Get();
 516                     }
 517                     else if (opcode == instruction.OP_PUSHDATA2)
 518                     {
 519                         // The next two bytes contain the number of bytes to be pushed onto the stack,
 520                         //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
 521                         codeBytes.Get(2).CopyTo(szBytes, 2);
 522                     }
 523                     else if (opcode == instruction.OP_PUSHDATA4)
 524                     {
 525                         // The next four bytes contain the number of bytes to be pushed onto the stack,
 526                         //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
 527                         szBytes = codeBytes.Get(4);
 528                     }
 529                 }
 530                 catch (ByteQueueException)
 531                 {
 532                     // Unable to read operand length
 533                     return false;
 534                 }
 535
 536                 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
 537
 538                 if (nSize > 0)
 539                 {
 540                     // If nSize is greater than zero then there is some data available
 541                     try
 542                     {
 543                         // Read found number of bytes into list of OP_PUSHDATAn arguments.
 544                         bytesRet = codeBytes.GetEnumerable(nSize);
 545                     }
 546                     catch (ByteQueueException)
 547                     {
 548                         // Unable to read data
 549                         return false;
 550                     }
 551                 }
 552             }
 553
 554             opcodeRet = opcode;
 555
 556             return true;
 557         }
 558
 559         /// <summary>
 560         /// Convert value bytes into readable representation.
 561         ///
 562         /// If list lengh is equal or lesser than 4 bytes then bytes are interpreted as integer value. Otherwise you will get hex representation of supplied data.
 563         /// </summary>
 564         /// <param name="bytes">Collection of value bytes.</param>
 565         /// <returns>Formatted value.</returns>
 566         public static string ValueString(IEnumerable<byte> bytes)
 567         {
 568             StringBuilder sb = new StringBuilder();
 569
 570             if (bytes.Count() <= 4)
 571             {
 572                 byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
 573                 bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());
 574
 575                 sb.Append(Interop.BEBytesToUInt32(valueBytes));
 576             }
 577             else
 578             {
 579                 return Interop.ToHex(bytes);
 580             }
 581
 582             return sb.ToString();
 583         }
 584
 585         /// <summary>
 586         /// Convert list of stack items into human readable representation.
 587         /// </summary>
 588         /// <param name="stackList">List of stack items.</param>
 589         /// <returns>Formatted value.</returns>
 590         public static string StackString(IList<IList<byte>> stackList)
 591         {
 592             StringBuilder sb = new StringBuilder();
 593             foreach (IList<byte> bytesList in stackList)
 594             {
 595                 sb.Append(ValueString(bytesList));
 596             }
 597
 598             return sb.ToString();
 599         }
 600
 601         /// <summary>
 602         /// Decode instruction to integer value
 603         /// </summary>
 604         /// <param name="opcode">Small integer opcode (OP_1_NEGATE and OP_0 - OP_16)</param>
 605         /// <returns>Small integer</returns>
 606         public static int DecodeOP_N(instruction opcode, bool AllowNegate=false)
 607         {
 608             if (AllowNegate && opcode == instruction.OP_1NEGATE)
 609             {
 610                 return -1;
 611             }
 612
 613             if (opcode == instruction.OP_0)
 614             {
 615                 return 0;
 616             }
 617
 618             // Only OP_n opcodes are supported, throw exception otherwise.
 619             if (opcode < instruction.OP_1 || opcode > instruction.OP_16)
 620             {
 621                 throw new Exception("Invalid integer instruction.");
 622             }
 623
 624             return (int)opcode - (int)(instruction.OP_1 - 1);
 625         }
 626
 627         /// <summary>
 628         /// Converts integer into instruction
 629         /// </summary>
 630         /// <param name="n">Small integer from the range of -1 up to 16.</param>
 631         /// <returns>Corresponding opcode.</returns>
 632         public static instruction EncodeOP_N(int n, bool allowNegate=false)
 633         {
 634             if (allowNegate && n == -1)
 635             {
 636                 return instruction.OP_1NEGATE;
 637             }
 638
 639             if (n == 0)
 640             {
 641                 return instruction.OP_0;
 642             }
 643
 644             // The n value must be in the range of 0 to 16.
 645             if (n < 0 || n > 16)
 646                 throw new Exception("Invalid integer value.");
 647             return (instruction.OP_1 + n - 1);
 648         }
 649
 650         public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
 651         {
 652             switch (t)
 653             {
 654                 case txnouttype.TX_NONSTANDARD:
 655                     return -1;
 656                 case txnouttype.TX_NULL_DATA:
 657                     return 1;
 658                 case txnouttype.TX_PUBKEY:
 659                     return 1;
 660                 case txnouttype.TX_PUBKEYHASH:
 661                     return 2;
 662                 case txnouttype.TX_MULTISIG:
 663                     if (solutions.Count() < 1 || solutions.First().Count() < 1)
 664                         return -1;
 665                     return solutions.First().First() + 1;
 666                 case txnouttype.TX_SCRIPTHASH:
 667                     return 1; // doesn't include args needed by the script
 668             }
 669             return -1;
 670         }
 671
 672         /// <summary>
 673         /// Is it a standart type of scriptPubKey?
 674         /// </summary>
 675         /// <param name="scriptPubKey">CScript instance</param>
 676         /// <param name="whichType">utut type</param>
 677         /// <returns>Checking result</returns>
 678         public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
 679         {
 680             IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();
 681
 682             if (!Solver(scriptPubKey, out whichType, out solutions))
 683             {
 684                 // No solutions found
 685                 return false;
 686             }
 687
 688             if (whichType == txnouttype.TX_MULTISIG)
 689             {
 690                 // Additional verification of OP_CHECKMULTISIG arguments
 691                 byte m = solutions.First().First();
 692                 byte n = solutions.Last().First();
 693
 694                 // Support up to x-of-3 multisig txns as standard
 695                 if (n < 1 || n > 3)
 696                 {
 697                     return false;
 698                 }
 699                 if (m < 1 || m > n)
 700                 {
 701                     return false;
 702                 }
 703             }
 704
 705             return whichType != txnouttype.TX_NONSTANDARD;
 706         }
 707
 708         /// <summary>
 709         /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
 710         /// </summary>
 711         /// <param name="scriptPubKey">CScript instance</param>
 712         /// <param name="typeRet">Output type</param>
 713         /// <param name="solutions">Set of solutions</param>
 714         /// <returns>Result</returns>
 715         public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
 716         {
 717             solutions = new List<IEnumerable<byte>>();
 718
 719             // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types.
 720
 721             // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
 722             if (scriptPubKey.IsPayToScriptHash)
 723             {
 724                 typeRet = txnouttype.TX_SCRIPTHASH;
 725
 726                 // Take 20 bytes with offset of 2 bytes
 727                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(2).Take(20);
 728                 solutions.Add(hashBytes);
 729
 730                 return true;
 731             }
 732
 733             // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 734             if (scriptPubKey.IsPayToPubKeyHash)
 735             {
 736                 typeRet = txnouttype.TX_PUBKEYHASH;
 737
 738                 // Take 20 bytes with offset of 3 bytes
 739                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(3).Take(20);
 740                 solutions.Add(hashBytes);
 741
 742                 return true;
 743             }
 744
 745             List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();
 746
 747             // Sender provides pubkey, receiver adds signature
 748             // [ECDSA public key] OP_CHECKSIG
 749             templateTuples.Add(
 750                 new Tuple<txnouttype, IEnumerable<byte>>(
 751                     txnouttype.TX_PUBKEY,
 752                     new byte[] {
 753                         (byte)instruction.OP_PUBKEY,
 754                         (byte)instruction.OP_CHECKSIG
 755                     })
 756             );
 757
 758             // Sender provides N pubkeys, receivers provides M signatures
 759             // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
 760             // Where N and M are small integer opcodes (OP1 ... OP_16)
 761             templateTuples.Add(
 762                 new Tuple<txnouttype, IEnumerable<byte>>(
 763                     txnouttype.TX_MULTISIG,
 764                     new byte[] {
 765                         (byte)instruction.OP_SMALLINTEGER,
 766                         (byte)instruction.OP_PUBKEYS,
 767                         (byte)instruction.OP_SMALLINTEGER,
 768                         (byte)instruction.OP_CHECKMULTISIG
 769                     })
 770             );
 771
 772             // Data-carrying output
 773             // OP_RETURN [up to 80 bytes of data]
 774             templateTuples.Add(
 775                 new Tuple<txnouttype, IEnumerable<byte>>(
 776                     txnouttype.TX_NULL_DATA,
 777                     new byte[] {
 778                         (byte)instruction.OP_RETURN,
 779                         (byte)instruction.OP_SMALLDATA
 780                     })
 781             );
 782
 783             // Nonstandard tx output
 784             typeRet = txnouttype.TX_NONSTANDARD;
 785
 786             foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
 787             {
 788                 CScript script1 = scriptPubKey;
 789                 CScript script2 = new CScript(templateTuple.Item2);
 790
 791                 instruction opcode1, opcode2;
 792
 793                 // Compare
 794                 ByteQueue bq1 = script1.GetByteQUeue();
 795                 ByteQueue bq2 = script2.GetByteQUeue();
 796
 797                 IEnumerable<byte> args1, args2;
 798
 799                 byte last1 = script1.Bytes.Last();
 800                 byte last2 = script2.Bytes.Last();
 801
 802                 while (true)
 803                 {
 804                     if (bq1.GetCurrent() == last1 && bq2.GetCurrent() == last2)
 805                     {
 806                         // Found a match
 807                         typeRet = templateTuple.Item1;
 808                         if (typeRet == txnouttype.TX_MULTISIG)
 809                         {
 810                             // Additional checks for TX_MULTISIG:
 811                             byte m = solutions.First().First();
 812                             byte n = solutions.Last().First();
 813
 814                             if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
 815                             {
 816                                 return false;
 817                             }
 818                         }
 819                         return true;
 820                     }
 821
 822                     if (!GetOp(ref bq1, out opcode1, out args1))
 823                     {
 824                         break;
 825                     }
 826                     if (!GetOp(ref bq2, out opcode2, out args2))
 827                     {
 828                         break;
 829                     }
 830
 831                     // Template matching opcodes:
 832                     if (opcode2 == instruction.OP_PUBKEYS)
 833                     {
 834                         while (args1.Count() >= 33 && args1.Count() <= 120)
 835                         {
 836                             solutions.Add(args1);
 837                             if (!GetOp(ref bq1, out opcode1, out args1))
 838                             {
 839                                 break;
 840                             }
 841                         }
 842                         if (!GetOp(ref bq2, out opcode2, out args2))
 843                             break;
 844                         // Normal situation is to fall through
 845                         // to other if/else statements
 846                     }
 847                     if (opcode2 == instruction.OP_PUBKEY)
 848                     {
 849                         if (args1.Count() < 33 || args1.Count() > 120)
 850                         {
 851                             break;
 852                         }
 853                         solutions.Add(args1);
 854                     }
 855                     else if (opcode2 == instruction.OP_PUBKEYHASH)
 856                     {
 857                         if (args1.Count() != 20) // hash160 size
 858                         {
 859                             break;
 860                         }
 861                         solutions.Add(args1);
 862                     }
 863                     else if (opcode2 == instruction.OP_SMALLINTEGER)
 864                     {
 865                         // Single-byte small integer pushed onto solutions
 866                         if (opcode1 == instruction.OP_0 || (opcode1 >= instruction.OP_1 && opcode1 <= instruction.OP_16))
 867                         {
 868                             byte n = (byte)DecodeOP_N(opcode1);
 869                             solutions.Add(new byte[] { n });
 870                         }
 871                         else
 872                         {
 873                             break;
 874                         }
 875                     }
 876                     else if (opcode2 == instruction.OP_SMALLDATA)
 877                     {
 878                         // small pushdata, <= 80 bytes
 879                         if (args1.Count() > 80)
 880                         {
 881                             break;
 882                         }
 883                     }
 884                     else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
 885                     {
 886                         // Others must match exactly
 887                         break;
 888                     }
 889                 }
 890             }
 891
 892             solutions.Clear();
 893             typeRet = txnouttype.TX_NONSTANDARD;
 894
 895             return false;
 896         }
 897
 898         public static Hash256 SignatureHash(CScript scriptCode, CTransaction txTo, int nIn, int nHashType)
 899         {
 900             if (nIn >= txTo.vin.Length)
 901             {
 902                 StringBuilder sb = new StringBuilder();
 903                 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
 904                 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
 905             }
 906
 907             CTransaction txTmp = new CTransaction(txTo);
 908
 909             // In case concatenating two scripts ends up with two codeseparators,
 910             // or an extra one at the end, this prevents all those possible incompatibilities.
 911             scriptCode.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
 912
 913             // Blank out other inputs' signatures
 914             for (int i = 0; i < txTmp.vin.Length; i++)
 915             {
 916                 txTmp.vin[i].scriptSig = new CScript();
 917             }
 918             txTmp.vin[nIn].scriptSig = scriptCode;
 919
 920             // Blank out some of the outputs
 921             if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
 922             {
 923                 // Wildcard payee
 924                 txTmp.vout = new CTxOut[0];
 925
 926                 // Let the others update at will
 927                 for (int i = 0; i < txTmp.vin.Length; i++)
 928                 {
 929                     if (i != nIn)
 930                     {
 931                         txTmp.vin[i].nSequence = 0;
 932                     }
 933                 }
 934             }
 935             else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
 936             {
 937                 // Only lock-in the txout payee at same index as txin
 938                 int nOut = nIn;
 939                 if (nOut >= txTmp.vout.Length)
 940                 {
 941                     StringBuilder sb = new StringBuilder();
 942                     sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
 943                     throw new ArgumentOutOfRangeException("nOut", sb.ToString());
 944                 }
 945                 Array.Resize(ref txTmp.vout, nOut + 1);
 946
 947                 for (int i = 0; i < nOut; i++)
 948                 {
 949                     txTmp.vout[i] = new CTxOut();
 950                 }
 951
 952                 // Let the others update at will
 953                 for (int i = 0; i < txTmp.vin.Length; i++)
 954                 {
 955                     if (i != nIn)
 956                     {
 957                         txTmp.vin[i].nSequence = 0;
 958                     }
 959                 }
 960             }
 961
 962             // Blank out other inputs completely, not recommended for open transactions
 963             if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
 964             {
 965                 txTmp.vin[0] = txTmp.vin[nIn];
 966                 Array.Resize(ref txTmp.vin, 1);
 967             }
 968
 969             // Serialize and hash
 970             List<byte> b = new List<byte>();
 971             b.AddRange(txTmp.Bytes);
 972             b.AddRange(BitConverter.GetBytes(nHashType));
 973
 974             return Hash256.Compute256(b);
 975         }
 976
 977         public class StackMachineException : Exception
 978         {
 979             public StackMachineException()
 980             {
 981             }
 982
 983             public StackMachineException(string message)
 984                 : base(message)
 985             {
 986             }
 987
 988             public StackMachineException(string message, Exception inner)
 989                 : base(message, inner)
 990             {
 991             }
 992         }
 993
 994
 995         //
 996         // Script is a stack machine (like Forth) that evaluates a predicate
 997         // returning a bool indicating valid or not.  There are no loops.
 998         //
 999
1000         /// <summary>
1001         /// Remove last element from stack
1002         /// </summary>
1003         /// <param name="stack">Stack reference</param>
1004         static void popstack(ref List<IEnumerable<byte>> stack)
1005         {
1006             int nCount = stack.Count;
1007             if (nCount == 0)
1008                 throw new StackMachineException("popstack() : stack empty");
1009             stack.RemoveAt(nCount - 1);
1010         }
1011
1012         /// <summary>
1013         /// Get element at specified stack depth
1014         /// </summary>
1015         /// <param name="stack">Stack reference</param>
1016         /// <param name="nDepth">Depth</param>
1017         /// <returns>Byte sequence</returns>
1018         static IEnumerable<byte> stacktop(ref List<IEnumerable<byte>> stack, int nDepth)
1019         {
1020             int nStackElement = stack.Count + nDepth;
1021
1022             if (nDepth >= 0)
1023             {
1024                 StringBuilder sb = new StringBuilder();
1025                 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
1026
1027                 throw new StackMachineException(sb.ToString());
1028             }
1029
1030             if (nStackElement < 0)
1031             {
1032                 StringBuilder sb = new StringBuilder();
1033                 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
1034
1035                 throw new StackMachineException(sb.ToString());
1036             }
1037
1038             return stack[nStackElement];
1039         }
1040
1041         /// <summary>
1042         /// Cast argument to boolean value
1043         /// </summary>
1044         /// <param name="value">Some byte sequence</param>
1045         /// <returns></returns>
1046         private static bool CastToBool(IEnumerable<byte> arg)
1047         {
1048             byte[] value = arg.ToArray();
1049
1050             for (var i = 0; i < value.Length; i++)
1051             {
1052                 if (value[i] != 0)
1053                 {
1054                     // Can be negative zero
1055                     if (i == value.Length - 1 && value[i] == 0x80)
1056                     {
1057                         return false;
1058                     }
1059
1060                     return true;
1061                 }
1062             }
1063
1064             return false;
1065         }
1066
1067         /// <summary>
1068         /// Cast argument to integer value
1069         /// </summary>
1070         /// <param name="value"></param>
1071         /// <returns></returns>
1072         private static BigInteger CastToBigInteger(IEnumerable<byte> value)
1073         {
1074             if (value.Count() > 4)
1075             {
1076                 throw new StackMachineException("CastToBigInteger() : overflow");
1077             }
1078
1079             return new BigInteger(value.ToArray());
1080         }
1081
1082         static bool EvalScript(ref List<IEnumerable<byte>> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
1083         {
1084             instruction opcode;
1085
1086             ByteQueue CodeQueue = script.GetByteQUeue();
1087
1088             List<bool> vfExec = new List<bool>();
1089             List<IEnumerable<byte>> altStack = new List<IEnumerable<byte>>();
1090
1091             byte[] falseBytes = new byte[0];
1092             byte[] trueBytes = new byte[] { 0x01 };
1093
1094             if (script.Bytes.Count() > 10000)
1095             {
1096                 return false; // Size limit failed
1097             }
1098
1099             int nOpCount = 0;
1100             int nCodeHashBegin = 0;
1101
1102             while (true)
1103             {
1104                 bool fExec = vfExec.IndexOf(false) != -1;
1105
1106                 //
1107                 // Read instruction
1108                 //
1109                 IEnumerable<byte> pushArg;
1110                 if (!GetOp(ref CodeQueue, out opcode, out pushArg))
1111                 {
1112                     return false; // No instructions left
1113                 }
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 opcode");
1624                                         break;
1625                                 }
1626
1627                                 popstack(ref stack);
1628                                 stack.Add(bn.ToByteArray());
1629                             }
1630                             break;
1631
1632                         case instruction.OP_ADD:
1633                         case instruction.OP_SUB:
1634                         case instruction.OP_BOOLAND:
1635                         case instruction.OP_BOOLOR:
1636                         case instruction.OP_NUMEQUAL:
1637                         case instruction.OP_NUMEQUALVERIFY:
1638                         case instruction.OP_NUMNOTEQUAL:
1639                         case instruction.OP_LESSTHAN:
1640                         case instruction.OP_GREATERTHAN:
1641                         case instruction.OP_LESSTHANOREQUAL:
1642                         case instruction.OP_GREATERTHANOREQUAL:
1643                         case instruction.OP_MIN:
1644                         case instruction.OP_MAX:
1645                             {
1646                                 // (x1 x2 -- out)
1647                                 if (stack.Count() < 2)
1648                                 {
1649                                     return false;
1650                                 }
1651
1652                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -2));
1653                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -1));
1654                                 BigInteger bn = 0;
1655
1656                                 switch (opcode)
1657                                 {
1658                                     case instruction.OP_ADD:
1659                                         bn = bn1 + bn2;
1660                                         break;
1661                                     case instruction.OP_SUB:
1662                                         bn = bn1 - bn2;
1663                                         break;
1664                                     case instruction.OP_BOOLAND:
1665                                         bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1666                                         break;
1667                                     case instruction.OP_BOOLOR:
1668                                         bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1669                                         break;
1670                                     case instruction.OP_NUMEQUAL:
1671                                         bn = (bn1 == bn2) ? 1 : 0;
1672                                         break;
1673                                     case instruction.OP_NUMEQUALVERIFY:
1674                                         bn = (bn1 == bn2) ? 1 : 0;
1675                                         break;
1676                                     case instruction.OP_NUMNOTEQUAL:
1677                                         bn = (bn1 != bn2) ? 1 : 0;
1678                                         break;
1679                                     case instruction.OP_LESSTHAN:
1680                                         bn = (bn1 < bn2) ? 1 : 0;
1681                                         break;
1682                                     case instruction.OP_GREATERTHAN:
1683                                         bn = (bn1 > bn2) ? 1 : 0;
1684                                         break;
1685                                     case instruction.OP_LESSTHANOREQUAL:
1686                                         bn = (bn1 <= bn2) ? 1 : 0;
1687                                         break;
1688                                     case instruction.OP_GREATERTHANOREQUAL:
1689                                         bn = (bn1 >= bn2) ? 1 : 0;
1690                                         break;
1691                                     case instruction.OP_MIN:
1692                                         bn = (bn1 < bn2 ? bn1 : bn2);
1693                                         break;
1694                                     case instruction.OP_MAX:
1695                                         bn = (bn1 > bn2 ? bn1 : bn2);
1696                                         break;
1697
1698                                     default:
1699                                         throw new StackMachineException("invalid opcode");
1700                                         break;
1701                                 }
1702
1703                                 popstack(ref stack);
1704                                 popstack(ref stack);
1705                                 stack.Add(bn.ToByteArray());
1706
1707                                 if (opcode == instruction.OP_NUMEQUALVERIFY)
1708                                 {
1709                                     if (CastToBool(stacktop(ref stack, -1)))
1710                                     {
1711                                         popstack(ref stack);
1712                                     }
1713                                     else
1714                                     {
1715                                         return false;
1716                                     }
1717                                 }
1718                             }
1719                             break;
1720
1721                         case instruction.OP_WITHIN:
1722                             {
1723                                 // (x min max -- out)
1724                                 if (stack.Count() < 3)
1725                                     return false;
1726                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -3));
1727                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -2));
1728                                 BigInteger bn3 = CastToBigInteger(stacktop(ref stack, -1));
1729                                 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1730                                 popstack(ref stack);
1731                                 popstack(ref stack);
1732                                 popstack(ref stack);
1733                                 stack.Add(fValue ? trueBytes : falseBytes);
1734                             }
1735                             break;
1736
1737
1738                         //
1739                         // Crypto
1740                         //
1741                         case instruction.OP_RIPEMD160:
1742                         case instruction.OP_SHA1:
1743                         case instruction.OP_SHA256:
1744                         case instruction.OP_HASH160:
1745                         case instruction.OP_HASH256:
1746                             {
1747                                 // (in -- hash)
1748                                 if (stack.Count() < 1)
1749                                     return false;
1750                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1751                                 IEnumerable<byte> vchHash = null;
1752                                 if (opcode == instruction.OP_RIPEMD160)
1753                                 {
1754                                     RIPEMD160 hash = RIPEMD160.Compute160(vch);
1755                                     vchHash = hash.hashBytes;
1756                                 }
1757                                 else if (opcode == instruction.OP_SHA1)
1758                                 {
1759                                     SHA1 hash = SHA1.Compute1(vch);
1760                                     vchHash = hash.hashBytes;
1761                                 }
1762                                 else if (opcode == instruction.OP_SHA256)
1763                                 {
1764                                     SHA256 hash = SHA256.Compute256(vch);
1765                                     vchHash = hash.hashBytes;
1766                                 }
1767                                 else if (opcode == instruction.OP_HASH160)
1768                                 {
1769                                     Hash160 hash = Hash160.Compute160(vch);
1770                                     vchHash = hash.hashBytes;
1771                                 }
1772                                 else if (opcode == instruction.OP_HASH256)
1773                                 {
1774                                     Hash256 hash = Hash256.Compute256(vch);
1775                                     vchHash = hash.hashBytes;
1776                                 }
1777                                 popstack(ref stack);
1778                                 stack.Add(vchHash);
1779                             }
1780                             break;
1781
1782                         case instruction.OP_CODESEPARATOR:
1783                             {
1784                                 // Hash starts after the code separator
1785                                 nCodeHashBegin = CodeQueue.CurrentIndex;
1786                             }
1787                             break;
1788
1789                         case instruction.OP_CHECKSIG:
1790                         case instruction.OP_CHECKSIGVERIFY:
1791                             {
1792                                 // (sig pubkey -- bool)
1793                                 if (stack.Count() < 2)
1794                                 {
1795                                     return false;
1796                                 }
1797
1798                                 IList<byte> sigBytes = stacktop(ref stack, -2).ToList();
1799                                 IList<byte> pubkeyBytes = stacktop(ref stack, -1).ToList();
1800
1801                                 // Subset of script starting at the most recent codeseparator
1802                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1803
1804                                 // There's no way for a signature to sign itself
1805                                 scriptCode.RemovePattern(sigBytes);
1806
1807                                 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes.ToList(), flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1808
1809                                 popstack(ref stack);
1810                                 popstack(ref stack);
1811                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1812                                 if (opcode == instruction.OP_CHECKSIGVERIFY)
1813                                 {
1814                                     if (fSuccess)
1815                                     {
1816                                         popstack(ref stack);
1817                                     }
1818                                     else
1819                                     {
1820                                         return false;
1821                                     }
1822                                 }
1823                             }
1824                             break;
1825
1826                         case instruction.OP_CHECKMULTISIG:
1827                         case instruction.OP_CHECKMULTISIGVERIFY:
1828                             {
1829                                 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1830
1831                                 int i = 1;
1832                                 if (stack.Count() < i)
1833                                 {
1834                                     return false;
1835                                 }
1836
1837                                 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1838                                 if (nKeysCount < 0 || nKeysCount > 20)
1839                                 {
1840                                     return false;
1841                                 }
1842                                 nOpCount += nKeysCount;
1843                                 if (nOpCount > 201)
1844                                 {
1845                                     return false;
1846                                 }
1847                                 int ikey = ++i;
1848                                 i += nKeysCount;
1849                                 if (stack.Count() < i)
1850                                 {
1851                                     return false;
1852                                 }
1853
1854                                 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1855                                 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1856                                 {
1857                                     return false;
1858                                 }
1859                                 int isig = ++i;
1860                                 i += nSigsCount;
1861                                 if (stack.Count() < i)
1862                                 {
1863                                     return false;
1864                                 }
1865
1866                                 // Subset of script starting at the most recent codeseparator
1867                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1868
1869                                 // There is no way for a signature to sign itself, so we need to drop the signatures
1870                                 for (int k = 0; k < nSigsCount; k++)
1871                                 {
1872                                     IEnumerable<byte> vchSig = stacktop(ref stack, -isig - k);
1873                                     scriptCode.RemovePattern(vchSig.ToList());
1874                                 }
1875
1876                                 bool fSuccess = true;
1877                                 while (fSuccess && nSigsCount > 0)
1878                                 {
1879                                     IList<byte> sigBytes = stacktop(ref stack, -isig).ToList();
1880                                     IList<byte> pubKeyBytes = stacktop(ref stack, -ikey).ToList();
1881
1882                                     // Check signature
1883                                     bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes.ToList(), flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1884
1885                                     if (fOk)
1886                                     {
1887                                         isig++;
1888                                         nSigsCount--;
1889                                     }
1890                                     ikey++;
1891                                     nKeysCount--;
1892
1893                                     // If there are more signatures left than keys left,
1894                                     // then too many signatures have failed
1895                                     if (nSigsCount > nKeysCount)
1896                                     {
1897                                         fSuccess = false;
1898                                     }
1899                                 }
1900
1901                                 while (i-- > 1)
1902                                 {
1903                                     popstack(ref stack);
1904                                 }
1905
1906                                 // A bug causes CHECKMULTISIG to consume one extra argument
1907                                 // whose contents were not checked in any way.
1908                                 //
1909                                 // Unfortunately this is a potential source of mutability,
1910                                 // so optionally verify it is exactly equal to zero prior
1911                                 // to removing it from the stack.
1912                                 if (stack.Count() < 1)
1913                                 {
1914                                     return false;
1915                                 }
1916                                 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1917                                 {
1918                                     return false; // CHECKMULTISIG dummy argument not null
1919                                 }
1920                                 popstack(ref stack);
1921
1922                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1923
1924                                 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1925                                 {
1926                                     if (fSuccess)
1927                                     {
1928                                         popstack(ref stack);
1929                                     }
1930                                     else
1931                                     {
1932                                         return false;
1933                                     }
1934                                 }
1935                             }
1936                             break;
1937
1938                         default:
1939                             return false;
1940                     }
1941
1942                 // Size limits
1943                 if (stack.Count() + altStack.Count() > 1000)
1944                 {
1945                     return false;
1946                 }
1947             }
1948
1949
1950             if (vfExec.Count() == 0)
1951             {
1952                 return false;
1953             }
1954
1955             return true;
1956         }
1957
1958
1959         static bool IsCanonicalPubKey(IList<byte> pubKeyBytes, int flags)
1960         {
1961             if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1962                 return true;
1963
1964             if (pubKeyBytes.Count() < 33)
1965                 return false;  // Non-canonical public key: too short
1966             if (pubKeyBytes[0] == 0x04)
1967             {
1968                 if (pubKeyBytes.Count() != 65)
1969                     return false; // Non-canonical public key: invalid length for uncompressed key
1970             }
1971             else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1972             {
1973                 if (pubKeyBytes.Count() != 33)
1974                     return false; // Non-canonical public key: invalid length for compressed key
1975             }
1976             else
1977             {
1978                 return false; // Non-canonical public key: compressed nor uncompressed
1979             }
1980             return true;
1981         }
1982
1983         static bool IsCanonicalSignature(IList<byte> sigBytes, int flags)
1984         {
1985             // STUB
1986
1987             return true;
1988         }
1989
1990
1991         static bool CheckSig(IList<byte> sigBytes, IList<byte> pubKeyBytes, CScript scriptCode, CTransaction txTo, int nIn, int nHashType, int flags)
1992         {
1993             // STUB
1994             return true;
1995         }
1996
1997 };
1998 }