Novacoin/ScriptCode.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Text;
   5
   6 using System.Numerics;
   7
   8 // using Org.BouncyCastle.Math;
   9
  10 namespace Novacoin
  11 {
  12     /// <summary>
  13     /// Script opcodes
  14     /// </summary>
  15     public enum instruction
  16     {
  17         // push value
  18         OP_0 = 0x00,
  19         OP_FALSE = OP_0,
  20         OP_PUSHDATA1 = 0x4c,
  21         OP_PUSHDATA2 = 0x4d,
  22         OP_PUSHDATA4 = 0x4e,
  23         OP_1NEGATE = 0x4f,
  24         OP_RESERVED = 0x50,
  25         OP_1 = 0x51,
  26         OP_TRUE = OP_1,
  27         OP_2 = 0x52,
  28         OP_3 = 0x53,
  29         OP_4 = 0x54,
  30         OP_5 = 0x55,
  31         OP_6 = 0x56,
  32         OP_7 = 0x57,
  33         OP_8 = 0x58,
  34         OP_9 = 0x59,
  35         OP_10 = 0x5a,
  36         OP_11 = 0x5b,
  37         OP_12 = 0x5c,
  38         OP_13 = 0x5d,
  39         OP_14 = 0x5e,
  40         OP_15 = 0x5f,
  41         OP_16 = 0x60,
  42
  43         // control
  44         OP_NOP = 0x61,
  45         OP_VER = 0x62,
  46         OP_IF = 0x63,
  47         OP_NOTIF = 0x64,
  48         OP_VERIF = 0x65,
  49         OP_VERNOTIF = 0x66,
  50         OP_ELSE = 0x67,
  51         OP_ENDIF = 0x68,
  52         OP_VERIFY = 0x69,
  53         OP_RETURN = 0x6a,
  54
  55         // stack ops
  56         OP_TOALTSTACK = 0x6b,
  57         OP_FROMALTSTACK = 0x6c,
  58         OP_2DROP = 0x6d,
  59         OP_2DUP = 0x6e,
  60         OP_3DUP = 0x6f,
  61         OP_2OVER = 0x70,
  62         OP_2ROT = 0x71,
  63         OP_2SWAP = 0x72,
  64         OP_IFDUP = 0x73,
  65         OP_DEPTH = 0x74,
  66         OP_DROP = 0x75,
  67         OP_DUP = 0x76,
  68         OP_NIP = 0x77,
  69         OP_OVER = 0x78,
  70         OP_PICK = 0x79,
  71         OP_ROLL = 0x7a,
  72         OP_ROT = 0x7b,
  73         OP_SWAP = 0x7c,
  74         OP_TUCK = 0x7d,
  75
  76         // splice ops
  77         OP_CAT = 0x7e,
  78         OP_SUBSTR = 0x7f,
  79         OP_LEFT = 0x80,
  80         OP_RIGHT = 0x81,
  81         OP_SIZE = 0x82,
  82
  83         // bit logic
  84         OP_INVERT = 0x83,
  85         OP_AND = 0x84,
  86         OP_OR = 0x85,
  87         OP_XOR = 0x86,
  88         OP_EQUAL = 0x87,
  89         OP_EQUALVERIFY = 0x88,
  90         OP_RESERVED1 = 0x89,
  91         OP_RESERVED2 = 0x8a,
  92
  93         // numeric
  94         OP_1ADD = 0x8b,
  95         OP_1SUB = 0x8c,
  96         OP_2MUL = 0x8d,
  97         OP_2DIV = 0x8e,
  98         OP_NEGATE = 0x8f,
  99         OP_ABS = 0x90,
 100         OP_NOT = 0x91,
 101         OP_0NOTEQUAL = 0x92,
 102
 103         OP_ADD = 0x93,
 104         OP_SUB = 0x94,
 105         OP_MUL = 0x95,
 106         OP_DIV = 0x96,
 107         OP_MOD = 0x97,
 108         OP_LSHIFT = 0x98,
 109         OP_RSHIFT = 0x99,
 110
 111         OP_BOOLAND = 0x9a,
 112         OP_BOOLOR = 0x9b,
 113         OP_NUMEQUAL = 0x9c,
 114         OP_NUMEQUALVERIFY = 0x9d,
 115         OP_NUMNOTEQUAL = 0x9e,
 116         OP_LESSTHAN = 0x9f,
 117         OP_GREATERTHAN = 0xa0,
 118         OP_LESSTHANOREQUAL = 0xa1,
 119         OP_GREATERTHANOREQUAL = 0xa2,
 120         OP_MIN = 0xa3,
 121         OP_MAX = 0xa4,
 122
 123         OP_WITHIN = 0xa5,
 124
 125         // crypto
 126         OP_RIPEMD160 = 0xa6,
 127         OP_SHA1 = 0xa7,
 128         OP_SHA256 = 0xa8,
 129         OP_HASH160 = 0xa9,
 130         OP_HASH256 = 0xaa,
 131         OP_CODESEPARATOR = 0xab,
 132         OP_CHECKSIG = 0xac,
 133         OP_CHECKSIGVERIFY = 0xad,
 134         OP_CHECKMULTISIG = 0xae,
 135         OP_CHECKMULTISIGVERIFY = 0xaf,
 136
 137         // expansion
 138         OP_NOP1 = 0xb0,
 139         OP_NOP2 = 0xb1,
 140         OP_NOP3 = 0xb2,
 141         OP_NOP4 = 0xb3,
 142         OP_NOP5 = 0xb4,
 143         OP_NOP6 = 0xb5,
 144         OP_NOP7 = 0xb6,
 145         OP_NOP8 = 0xb7,
 146         OP_NOP9 = 0xb8,
 147         OP_NOP10 = 0xb9,
 148
 149         // template matching params
 150         OP_SMALLDATA = 0xf9,
 151         OP_SMALLINTEGER = 0xfa,
 152         OP_PUBKEYS = 0xfb,
 153         OP_PUBKEYHASH = 0xfd,
 154         OP_PUBKEY = 0xfe,
 155
 156         OP_INVALIDOPCODE = 0xff,
 157     };
 158
 159     /// <summary>
 160     /// Transaction output types.
 161     /// </summary>
 162     public enum txnouttype
 163     {
 164         TX_NONSTANDARD,
 165
 166         // 'standard' transaction types:
 167         TX_PUBKEY,
 168         TX_PUBKEYHASH,
 169         TX_SCRIPTHASH,
 170         TX_MULTISIG,
 171         TX_NULL_DATA,
 172     };
 173
 174     /// <summary>
 175     /// Signature hash types/flags
 176     /// </summary>
 177     public enum sigflag
 178     {
 179         SIGHASH_ALL = 1,
 180         SIGHASH_NONE = 2,
 181         SIGHASH_SINGLE = 3,
 182         SIGHASH_ANYONECANPAY = 0x80,
 183     };
 184
 185     /** Script verification flags */
 186     public enum scriptflag
 187     {
 188         SCRIPT_VERIFY_NONE = 0,
 189         SCRIPT_VERIFY_P2SH = (1 << 0), // evaluate P2SH (BIP16) subscripts
 190         SCRIPT_VERIFY_STRICTENC = (1 << 1), // enforce strict conformance to DER and SEC2 for signatures and pubkeys
 191         SCRIPT_VERIFY_LOW_S = (1 << 2), // enforce low S values in signatures (depends on STRICTENC)
 192         SCRIPT_VERIFY_NOCACHE = (1 << 3), // do not store results in signature cache (but do query it)
 193         SCRIPT_VERIFY_NULLDUMMY = (1 << 4), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
 194     };
 195
 196     public static class ScriptCode
 197     {
 198         public static string GetTxnOutputType(txnouttype t)
 199         {
 200             switch (t)
 201             {
 202                 case txnouttype.TX_NONSTANDARD: return "nonstandard";
 203                 case txnouttype.TX_PUBKEY: return "pubkey";
 204                 case txnouttype.TX_PUBKEYHASH: return "pubkeyhash";
 205                 case txnouttype.TX_SCRIPTHASH: return "scripthash";
 206                 case txnouttype.TX_MULTISIG: return "multisig";
 207                 case txnouttype.TX_NULL_DATA: return "nulldata";
 208             }
 209             return string.Empty;
 210         }
 211
 212         /// <summary>
 213         /// Get the name of supplied opcode
 214         /// </summary>
 215         /// <param name="opcode">Opcode</param>
 216         /// <returns>Opcode name</returns>
 217         public static string GetOpName(instruction opcode)
 218         {
 219             switch (opcode)
 220             {
 221                 // push value
 222                 case instruction.OP_0:
 223                     return "OP_0";
 224                 case instruction.OP_PUSHDATA1:
 225                     return "OP_PUSHDATA1";
 226                 case instruction.OP_PUSHDATA2:
 227                     return "OP_PUSHDATA2";
 228                 case instruction.OP_PUSHDATA4:
 229                     return "OP_PUSHDATA4";
 230                 case instruction.OP_1NEGATE:
 231                     return "OP_1NEGATE";
 232                 case instruction.OP_RESERVED:
 233                     return "OP_RESERVED";
 234                 case instruction.OP_1:
 235                     return "OP_1";
 236                 case instruction.OP_2:
 237                     return "OP_2";
 238                 case instruction.OP_3:
 239                     return "OP_3";
 240                 case instruction.OP_4:
 241                     return "OP_4";
 242                 case instruction.OP_5:
 243                     return "OP_5";
 244                 case instruction.OP_6:
 245                     return "OP_6";
 246                 case instruction.OP_7:
 247                     return "OP_7";
 248                 case instruction.OP_8:
 249                     return "OP_8";
 250                 case instruction.OP_9:
 251                     return "OP_9";
 252                 case instruction.OP_10:
 253                     return "OP_10";
 254                 case instruction.OP_11:
 255                     return "OP_11";
 256                 case instruction.OP_12:
 257                     return "OP_12";
 258                 case instruction.OP_13:
 259                     return "OP_13";
 260                 case instruction.OP_14:
 261                     return "OP_14";
 262                 case instruction.OP_15:
 263                     return "OP_15";
 264                 case instruction.OP_16:
 265                     return "OP_16";
 266
 267                 // control
 268                 case instruction.OP_NOP:
 269                     return "OP_NOP";
 270                 case instruction.OP_VER:
 271                     return "OP_VER";
 272                 case instruction.OP_IF:
 273                     return "OP_IF";
 274                 case instruction.OP_NOTIF:
 275                     return "OP_NOTIF";
 276                 case instruction.OP_VERIF:
 277                     return "OP_VERIF";
 278                 case instruction.OP_VERNOTIF:
 279                     return "OP_VERNOTIF";
 280                 case instruction.OP_ELSE:
 281                     return "OP_ELSE";
 282                 case instruction.OP_ENDIF:
 283                     return "OP_ENDIF";
 284                 case instruction.OP_VERIFY:
 285                     return "OP_VERIFY";
 286                 case instruction.OP_RETURN:
 287                     return "OP_RETURN";
 288
 289                 // stack ops
 290                 case instruction.OP_TOALTSTACK:
 291                     return "OP_TOALTSTACK";
 292                 case instruction.OP_FROMALTSTACK:
 293                     return "OP_FROMALTSTACK";
 294                 case instruction.OP_2DROP:
 295                     return "OP_2DROP";
 296                 case instruction.OP_2DUP:
 297                     return "OP_2DUP";
 298                 case instruction.OP_3DUP:
 299                     return "OP_3DUP";
 300                 case instruction.OP_2OVER:
 301                     return "OP_2OVER";
 302                 case instruction.OP_2ROT:
 303                     return "OP_2ROT";
 304                 case instruction.OP_2SWAP:
 305                     return "OP_2SWAP";
 306                 case instruction.OP_IFDUP:
 307                     return "OP_IFDUP";
 308                 case instruction.OP_DEPTH:
 309                     return "OP_DEPTH";
 310                 case instruction.OP_DROP:
 311                     return "OP_DROP";
 312                 case instruction.OP_DUP:
 313                     return "OP_DUP";
 314                 case instruction.OP_NIP:
 315                     return "OP_NIP";
 316                 case instruction.OP_OVER:
 317                     return "OP_OVER";
 318                 case instruction.OP_PICK:
 319                     return "OP_PICK";
 320                 case instruction.OP_ROLL:
 321                     return "OP_ROLL";
 322                 case instruction.OP_ROT:
 323                     return "OP_ROT";
 324                 case instruction.OP_SWAP:
 325                     return "OP_SWAP";
 326                 case instruction.OP_TUCK:
 327                     return "OP_TUCK";
 328
 329                 // splice ops
 330                 case instruction.OP_CAT:
 331                     return "OP_CAT";
 332                 case instruction.OP_SUBSTR:
 333                     return "OP_SUBSTR";
 334                 case instruction.OP_LEFT:
 335                     return "OP_LEFT";
 336                 case instruction.OP_RIGHT:
 337                     return "OP_RIGHT";
 338                 case instruction.OP_SIZE:
 339                     return "OP_SIZE";
 340
 341                 // bit logic
 342                 case instruction.OP_INVERT:
 343                     return "OP_INVERT";
 344                 case instruction.OP_AND:
 345                     return "OP_AND";
 346                 case instruction.OP_OR:
 347                     return "OP_OR";
 348                 case instruction.OP_XOR:
 349                     return "OP_XOR";
 350                 case instruction.OP_EQUAL:
 351                     return "OP_EQUAL";
 352                 case instruction.OP_EQUALVERIFY:
 353                     return "OP_EQUALVERIFY";
 354                 case instruction.OP_RESERVED1:
 355                     return "OP_RESERVED1";
 356                 case instruction.OP_RESERVED2:
 357                     return "OP_RESERVED2";
 358
 359                 // numeric
 360                 case instruction.OP_1ADD:
 361                     return "OP_1ADD";
 362                 case instruction.OP_1SUB:
 363                     return "OP_1SUB";
 364                 case instruction.OP_2MUL:
 365                     return "OP_2MUL";
 366                 case instruction.OP_2DIV:
 367                     return "OP_2DIV";
 368                 case instruction.OP_NEGATE:
 369                     return "OP_NEGATE";
 370                 case instruction.OP_ABS:
 371                     return "OP_ABS";
 372                 case instruction.OP_NOT:
 373                     return "OP_NOT";
 374                 case instruction.OP_0NOTEQUAL:
 375                     return "OP_0NOTEQUAL";
 376                 case instruction.OP_ADD:
 377                     return "OP_ADD";
 378                 case instruction.OP_SUB:
 379                     return "OP_SUB";
 380                 case instruction.OP_MUL:
 381                     return "OP_MUL";
 382                 case instruction.OP_DIV:
 383                     return "OP_DIV";
 384                 case instruction.OP_MOD:
 385                     return "OP_MOD";
 386                 case instruction.OP_LSHIFT:
 387                     return "OP_LSHIFT";
 388                 case instruction.OP_RSHIFT:
 389                     return "OP_RSHIFT";
 390                 case instruction.OP_BOOLAND:
 391                     return "OP_BOOLAND";
 392                 case instruction.OP_BOOLOR:
 393                     return "OP_BOOLOR";
 394                 case instruction.OP_NUMEQUAL:
 395                     return "OP_NUMEQUAL";
 396                 case instruction.OP_NUMEQUALVERIFY:
 397                     return "OP_NUMEQUALVERIFY";
 398                 case instruction.OP_NUMNOTEQUAL:
 399                     return "OP_NUMNOTEQUAL";
 400                 case instruction.OP_LESSTHAN:
 401                     return "OP_LESSTHAN";
 402                 case instruction.OP_GREATERTHAN:
 403                     return "OP_GREATERTHAN";
 404                 case instruction.OP_LESSTHANOREQUAL:
 405                     return "OP_LESSTHANOREQUAL";
 406                 case instruction.OP_GREATERTHANOREQUAL:
 407                     return "OP_GREATERTHANOREQUAL";
 408                 case instruction.OP_MIN:
 409                     return "OP_MIN";
 410                 case instruction.OP_MAX:
 411                     return "OP_MAX";
 412                 case instruction.OP_WITHIN:
 413                     return "OP_WITHIN";
 414
 415                 // crypto
 416                 case instruction.OP_RIPEMD160:
 417                     return "OP_RIPEMD160";
 418                 case instruction.OP_SHA1:
 419                     return "OP_SHA1";
 420                 case instruction.OP_SHA256:
 421                     return "OP_SHA256";
 422                 case instruction.OP_HASH160:
 423                     return "OP_HASH160";
 424                 case instruction.OP_HASH256:
 425                     return "OP_HASH256";
 426                 case instruction.OP_CODESEPARATOR:
 427                     return "OP_CODESEPARATOR";
 428                 case instruction.OP_CHECKSIG:
 429                     return "OP_CHECKSIG";
 430                 case instruction.OP_CHECKSIGVERIFY:
 431                     return "OP_CHECKSIGVERIFY";
 432                 case instruction.OP_CHECKMULTISIG:
 433                     return "OP_CHECKMULTISIG";
 434                 case instruction.OP_CHECKMULTISIGVERIFY:
 435                     return "OP_CHECKMULTISIGVERIFY";
 436
 437                 // expansion
 438                 case instruction.OP_NOP1:
 439                     return "OP_NOP1";
 440                 case instruction.OP_NOP2:
 441                     return "OP_NOP2";
 442                 case instruction.OP_NOP3:
 443                     return "OP_NOP3";
 444                 case instruction.OP_NOP4:
 445                     return "OP_NOP4";
 446                 case instruction.OP_NOP5:
 447                     return "OP_NOP5";
 448                 case instruction.OP_NOP6:
 449                     return "OP_NOP6";
 450                 case instruction.OP_NOP7:
 451                     return "OP_NOP7";
 452                 case instruction.OP_NOP8:
 453                     return "OP_NOP8";
 454                 case instruction.OP_NOP9:
 455                     return "OP_NOP9";
 456                 case instruction.OP_NOP10:
 457                     return "OP_NOP10";
 458
 459                 // template matching params
 460                 case instruction.OP_SMALLINTEGER:
 461                     return "OP_SMALLINTEGER";
 462                 case instruction.OP_PUBKEYHASH:
 463                     return "OP_PUBKEYHASH";
 464                 case instruction.OP_PUBKEY:
 465                     return "OP_PUBKEY";
 466                 case instruction.OP_PUBKEYS:
 467                     return "OP_PUBKEYS";
 468                 case instruction.OP_SMALLDATA:
 469                     return "OP_SMALLDATA";
 470
 471                 case instruction.OP_INVALIDOPCODE:
 472                     return "OP_INVALIDOPCODE";
 473                 default:
 474                     return "OP_UNKNOWN";
 475             }
 476         }
 477
 478         /// <summary>
 479         /// Get next opcode from passed list of bytes and extract push arguments if there are some.
 480         /// </summary>
 481         /// <param name="codeBytes">ByteQueue reference.</param>
 482         /// <param name="opcodeRet">Found opcode.</param>
 483         /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
 484         /// <returns>Result of operation</returns>
 485         public static bool GetOp(ref ByteQueue codeBytes, out instruction opcodeRet, out IEnumerable<byte> bytesRet)
 486         {
 487             bytesRet = new List<byte>();
 488             opcodeRet = instruction.OP_INVALIDOPCODE;
 489
 490             instruction opcode;
 491
 492             try
 493             {
 494                 // Read instruction
 495                 opcode = (instruction)codeBytes.Get();
 496             }
 497             catch (ByteQueueException)
 498             {
 499                 // No instruction found there
 500                 return false;
 501             }
 502
 503             // Immediate operand
 504             if (opcode <= instruction.OP_PUSHDATA4)
 505             {
 506                 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
 507
 508                 try
 509                 {
 510                     if (opcode < instruction.OP_PUSHDATA1)
 511                     {
 512                         // Zero value opcodes (OP_0, OP_FALSE)
 513                         szBytes[3] = (byte)opcode;
 514                     }
 515                     else if (opcode == instruction.OP_PUSHDATA1)
 516                     {
 517                         // The next byte contains the number of bytes to be pushed onto the stack,
 518                         //    i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
 519                         szBytes[3] = (byte)codeBytes.Get();
 520                     }
 521                     else if (opcode == instruction.OP_PUSHDATA2)
 522                     {
 523                         // The next two bytes contain the number of bytes to be pushed onto the stack,
 524                         //    i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
 525                         codeBytes.Get(2).CopyTo(szBytes, 2);
 526                     }
 527                     else if (opcode == instruction.OP_PUSHDATA4)
 528                     {
 529                         // The next four bytes contain the number of bytes to be pushed onto the stack,
 530                         //   OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
 531                         szBytes = codeBytes.Get(4);
 532                     }
 533                 }
 534                 catch (ByteQueueException)
 535                 {
 536                     // Unable to read operand length
 537                     return false;
 538                 }
 539
 540                 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
 541
 542                 if (nSize > 0)
 543                 {
 544                     // If nSize is greater than zero then there is some data available
 545                     try
 546                     {
 547                         // Read found number of bytes into list of OP_PUSHDATAn arguments.
 548                         bytesRet = codeBytes.GetEnumerable(nSize);
 549                     }
 550                     catch (ByteQueueException)
 551                     {
 552                         // Unable to read data
 553                         return false;
 554                     }
 555                 }
 556             }
 557
 558             opcodeRet = opcode;
 559
 560             return true;
 561         }
 562
 563         /// <summary>
 564         /// Convert value bytes into readable representation.
 565         ///
 566         /// If list lengh is equal or lesser than 4 bytes then bytes are interpreted as integer value. Otherwise you will get hex representation of supplied data.
 567         /// </summary>
 568         /// <param name="bytes">Collection of value bytes.</param>
 569         /// <returns>Formatted value.</returns>
 570         public static string ValueString(IEnumerable<byte> bytes)
 571         {
 572             StringBuilder sb = new StringBuilder();
 573
 574             if (bytes.Count() <= 4)
 575             {
 576                 byte[] valueBytes = new byte[4] { 0, 0, 0, 0 };
 577                 bytes.ToArray().CopyTo(valueBytes, valueBytes.Length - bytes.Count());
 578
 579                 sb.Append(Interop.BEBytesToUInt32(valueBytes));
 580             }
 581             else
 582             {
 583                 return Interop.ToHex(bytes);
 584             }
 585
 586             return sb.ToString();
 587         }
 588
 589         /// <summary>
 590         /// Convert list of stack items into human readable representation.
 591         /// </summary>
 592         /// <param name="stackList">List of stack items.</param>
 593         /// <returns>Formatted value.</returns>
 594         public static string StackString(IList<IList<byte>> stackList)
 595         {
 596             StringBuilder sb = new StringBuilder();
 597             foreach (IList<byte> bytesList in stackList)
 598             {
 599                 sb.Append(ValueString(bytesList));
 600             }
 601
 602             return sb.ToString();
 603         }
 604
 605         /// <summary>
 606         /// Decode instruction to integer value
 607         /// </summary>
 608         /// <param name="opcode">Small integer opcode (OP_1_NEGATE and OP_0 - OP_16)</param>
 609         /// <returns>Small integer</returns>
 610         public static int DecodeOP_N(instruction opcode, bool AllowNegate = false)
 611         {
 612             if (AllowNegate && opcode == instruction.OP_1NEGATE)
 613             {
 614                 return -1;
 615             }
 616
 617             if (opcode == instruction.OP_0)
 618             {
 619                 return 0;
 620             }
 621
 622             // Only OP_n opcodes are supported, throw exception otherwise.
 623             if (opcode < instruction.OP_1 || opcode > instruction.OP_16)
 624             {
 625                 throw new ArgumentException("Invalid integer instruction.");
 626             }
 627
 628             return (int)opcode - (int)(instruction.OP_1 - 1);
 629         }
 630
 631         /// <summary>
 632         /// Converts integer into instruction
 633         /// </summary>
 634         /// <param name="n">Small integer from the range of -1 up to 16.</param>
 635         /// <returns>Corresponding opcode.</returns>
 636         public static instruction EncodeOP_N(int n, bool allowNegate = false)
 637         {
 638             if (allowNegate && n == -1)
 639             {
 640                 return instruction.OP_1NEGATE;
 641             }
 642
 643             if (n == 0)
 644             {
 645                 return instruction.OP_0;
 646             }
 647
 648             // The n value must be in the range of 0 to 16.
 649             if (n < 0 || n > 16)
 650                 throw new ArgumentException("Invalid integer value.");
 651             return (instruction.OP_1 + n - 1);
 652         }
 653
 654         public static int ScriptSigArgsExpected(txnouttype t, IList<IEnumerable<byte>> solutions)
 655         {
 656             switch (t)
 657             {
 658                 case txnouttype.TX_NONSTANDARD:
 659                     return -1;
 660                 case txnouttype.TX_NULL_DATA:
 661                     return 1;
 662                 case txnouttype.TX_PUBKEY:
 663                     return 1;
 664                 case txnouttype.TX_PUBKEYHASH:
 665                     return 2;
 666                 case txnouttype.TX_MULTISIG:
 667                     if (solutions.Count() < 1 || solutions.First().Count() < 1)
 668                         return -1;
 669                     return solutions.First().First() + 1;
 670                 case txnouttype.TX_SCRIPTHASH:
 671                     return 1; // doesn't include args needed by the script
 672             }
 673             return -1;
 674         }
 675
 676         /// <summary>
 677         /// Is it a standart type of scriptPubKey?
 678         /// </summary>
 679         /// <param name="scriptPubKey">CScript instance</param>
 680         /// <param name="whichType">utut type</param>
 681         /// <returns>Checking result</returns>
 682         public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
 683         {
 684             IList<IEnumerable<byte>> solutions = new List<IEnumerable<byte>>();
 685
 686             if (!Solver(scriptPubKey, out whichType, out solutions))
 687             {
 688                 // No solutions found
 689                 return false;
 690             }
 691
 692             if (whichType == txnouttype.TX_MULTISIG)
 693             {
 694                 // Additional verification of OP_CHECKMULTISIG arguments
 695                 byte m = solutions.First().First();
 696                 byte n = solutions.Last().First();
 697
 698                 // Support up to x-of-3 multisig txns as standard
 699                 if (n < 1 || n > 3)
 700                 {
 701                     return false;
 702                 }
 703                 if (m < 1 || m > n)
 704                 {
 705                     return false;
 706                 }
 707             }
 708
 709             return whichType != txnouttype.TX_NONSTANDARD;
 710         }
 711
 712         /// <summary>
 713         /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
 714         /// </summary>
 715         /// <param name="scriptPubKey">CScript instance</param>
 716         /// <param name="typeRet">Output type</param>
 717         /// <param name="solutions">Set of solutions</param>
 718         /// <returns>Result</returns>
 719         public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<IEnumerable<byte>> solutions)
 720         {
 721             solutions = new List<IEnumerable<byte>>();
 722
 723             // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types.
 724
 725             // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
 726             if (scriptPubKey.IsPayToScriptHash)
 727             {
 728                 typeRet = txnouttype.TX_SCRIPTHASH;
 729
 730                 // Take 20 bytes with offset of 2 bytes
 731                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(2).Take(20);
 732                 solutions.Add(hashBytes);
 733
 734                 return true;
 735             }
 736
 737             // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
 738             if (scriptPubKey.IsPayToPubKeyHash)
 739             {
 740                 typeRet = txnouttype.TX_PUBKEYHASH;
 741
 742                 // Take 20 bytes with offset of 3 bytes
 743                 IEnumerable<byte> hashBytes = scriptPubKey.Bytes.Skip(3).Take(20);
 744                 solutions.Add(hashBytes);
 745
 746                 return true;
 747             }
 748
 749             List<Tuple<txnouttype, IEnumerable<byte>>> templateTuples = new List<Tuple<txnouttype, IEnumerable<byte>>>();
 750
 751             // Sender provides pubkey, receiver adds signature
 752             // [ECDSA public key] OP_CHECKSIG
 753             templateTuples.Add(
 754                 new Tuple<txnouttype, IEnumerable<byte>>(
 755                     txnouttype.TX_PUBKEY,
 756                     new byte[] {
 757                         (byte)instruction.OP_PUBKEY,
 758                         (byte)instruction.OP_CHECKSIG
 759                     })
 760             );
 761
 762             // Sender provides N pubkeys, receivers provides M signatures
 763             // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
 764             // Where N and M are small integer opcodes (OP1 ... OP_16)
 765             templateTuples.Add(
 766                 new Tuple<txnouttype, IEnumerable<byte>>(
 767                     txnouttype.TX_MULTISIG,
 768                     new byte[] {
 769                         (byte)instruction.OP_SMALLINTEGER,
 770                         (byte)instruction.OP_PUBKEYS,
 771                         (byte)instruction.OP_SMALLINTEGER,
 772                         (byte)instruction.OP_CHECKMULTISIG
 773                     })
 774             );
 775
 776             // Data-carrying output
 777             // OP_RETURN [up to 80 bytes of data]
 778             templateTuples.Add(
 779                 new Tuple<txnouttype, IEnumerable<byte>>(
 780                     txnouttype.TX_NULL_DATA,
 781                     new byte[] {
 782                         (byte)instruction.OP_RETURN,
 783                         (byte)instruction.OP_SMALLDATA
 784                     })
 785             );
 786
 787             // Nonstandard tx output
 788             typeRet = txnouttype.TX_NONSTANDARD;
 789
 790             foreach (Tuple<txnouttype, IEnumerable<byte>> templateTuple in templateTuples)
 791             {
 792                 CScript script1 = scriptPubKey;
 793                 CScript script2 = new CScript(templateTuple.Item2);
 794
 795                 instruction opcode1, opcode2;
 796
 797                 // Compare
 798                 ByteQueue bq1 = script1.GetByteQUeue();
 799                 ByteQueue bq2 = script2.GetByteQUeue();
 800
 801                 IEnumerable<byte> args1, args2;
 802
 803                 int last1 = script1.Bytes.Count() -1;
 804                 int last2 = script2.Bytes.Count() - 1;
 805
 806                 while (true)
 807                 {
 808                     if (bq1.CurrentIndex == last1 && bq2.CurrentIndex == last2)
 809                     {
 810                         // Found a match
 811                         typeRet = templateTuple.Item1;
 812                         if (typeRet == txnouttype.TX_MULTISIG)
 813                         {
 814                             // Additional checks for TX_MULTISIG:
 815                             byte m = solutions.First().First();
 816                             byte n = solutions.Last().First();
 817
 818                             if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
 819                             {
 820                                 return false;
 821                             }
 822                         }
 823                         return true;
 824                     }
 825
 826                     if (!GetOp(ref bq1, out opcode1, out args1))
 827                     {
 828                         break;
 829                     }
 830                     if (!GetOp(ref bq2, out opcode2, out args2))
 831                     {
 832                         break;
 833                     }
 834
 835                     // Template matching opcodes:
 836                     if (opcode2 == instruction.OP_PUBKEYS)
 837                     {
 838                         while (args1.Count() >= 33 && args1.Count() <= 120)
 839                         {
 840                             solutions.Add(args1);
 841                             if (!GetOp(ref bq1, out opcode1, out args1))
 842                             {
 843                                 break;
 844                             }
 845                         }
 846                         if (!GetOp(ref bq2, out opcode2, out args2))
 847                         {
 848                             break;
 849                         }
 850                         // Normal situation is to fall through
 851                         // to other if/else statements
 852                     }
 853                     if (opcode2 == instruction.OP_PUBKEY)
 854                     {
 855                         int PubKeyLen = args1.Count();
 856                         if (PubKeyLen < 33 || PubKeyLen > 120)
 857                         {
 858                             break;
 859                         }
 860                         solutions.Add(args1);
 861                     }
 862                     else if (opcode2 == instruction.OP_PUBKEYHASH)
 863                     {
 864                         if (args1.Count() != 20) // hash160 size
 865                         {
 866                             break;
 867                         }
 868                         solutions.Add(args1);
 869                     }
 870                     else if (opcode2 == instruction.OP_SMALLINTEGER)
 871                     {
 872                         // Single-byte small integer pushed onto solutions
 873                         try
 874                         {
 875                             byte n = (byte)DecodeOP_N(opcode1);
 876                             solutions.Add(new byte[] { n });
 877                         }
 878                         catch (Exception)
 879                         {
 880                             break;
 881                         }
 882                     }
 883                     else if (opcode2 == instruction.OP_SMALLDATA)
 884                     {
 885                         // small pushdata, <= 80 bytes
 886                         if (args1.Count() > 80)
 887                         {
 888                             break;
 889                         }
 890                     }
 891                     else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
 892                     {
 893                         // Others must match exactly
 894                         break;
 895                     }
 896                 }
 897             }
 898
 899             solutions.Clear();
 900             typeRet = txnouttype.TX_NONSTANDARD;
 901
 902             return false;
 903         }
 904
 905         /// <summary>
 906         /// Generation of SignatureHash. This method is responsible for removal of transaction metadata. It's necessary signature can't sign itself.
 907         /// </summary>
 908         /// <param name="script">Spending instructions</param>
 909         /// <param name="txTo">Instance of transaction</param>
 910         /// <param name="nIn">Input number</param>
 911         /// <param name="nHashType">Hash type flag</param>
 912         /// <returns></returns>
 913         public static Hash256 SignatureHash(CScript script, CTransaction txTo, int nIn, int nHashType)
 914         {
 915             if (nIn >= txTo.vin.Length)
 916             {
 917                 StringBuilder sb = new StringBuilder();
 918                 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
 919                 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
 920             }
 921
 922             // Init a copy of transaction
 923             CTransaction txTmp = new CTransaction(txTo);
 924
 925             // In case concatenating two scripts ends up with two codeseparators,
 926             // or an extra one at the end, this prevents all those possible incompatibilities.
 927             script.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
 928
 929             // Blank out other inputs' signatures
 930             for (int i = 0; i < txTmp.vin.Length; i++)
 931             {
 932                 txTmp.vin[i].scriptSig = new CScript();
 933             }
 934             txTmp.vin[nIn].scriptSig = script;
 935
 936             // Blank out some of the outputs
 937             if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
 938             {
 939                 // Wildcard payee
 940                 txTmp.vout = new CTxOut[0];
 941
 942                 // Let the others update at will
 943                 for (int i = 0; i < txTmp.vin.Length; i++)
 944                 {
 945                     if (i != nIn)
 946                     {
 947                         txTmp.vin[i].nSequence = 0;
 948                     }
 949                 }
 950             }
 951             else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
 952             {
 953                 // Only lock-in the txout payee at same index as txin
 954                 int nOut = nIn;
 955                 if (nOut >= txTmp.vout.Length)
 956                 {
 957                     StringBuilder sb = new StringBuilder();
 958                     sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
 959                     throw new ArgumentOutOfRangeException("nOut", sb.ToString());
 960                 }
 961                 Array.Resize(ref txTmp.vout, nOut + 1);
 962
 963                 for (int i = 0; i < nOut; i++)
 964                 {
 965                     txTmp.vout[i] = new CTxOut();
 966                 }
 967
 968                 // Let the others update at will
 969                 for (int i = 0; i < txTmp.vin.Length; i++)
 970                 {
 971                     if (i != nIn)
 972                     {
 973                         txTmp.vin[i].nSequence = 0;
 974                     }
 975                 }
 976             }
 977
 978             // Blank out other inputs completely, not recommended for open transactions
 979             if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
 980             {
 981                 txTmp.vin[0] = txTmp.vin[nIn];
 982                 Array.Resize(ref txTmp.vin, 1);
 983             }
 984
 985             // Serialize and hash
 986             List<byte> b = new List<byte>();
 987             b.AddRange(txTmp.Bytes);
 988             b.AddRange(BitConverter.GetBytes(nHashType));
 989
 990             return Hash256.Compute256(b);
 991         }
 992
 993         //
 994         // Script is a stack machine (like Forth) that evaluates a predicate
 995         // returning a bool indicating valid or not.  There are no loops.
 996         //
 997
 998         /// <summary>
 999         /// Script machine exception
1000         /// </summary>
1001         public class StackMachineException : Exception
1002         {
1003             public StackMachineException()
1004             {
1005             }
1006
1007             public StackMachineException(string message)
1008                 : base(message)
1009             {
1010             }
1011
1012             public StackMachineException(string message, Exception inner)
1013                 : base(message, inner)
1014             {
1015             }
1016         }
1017
1018         /// <summary>
1019         /// Remove last element from stack
1020         /// </summary>
1021         /// <param name="stack">Stack reference</param>
1022         static void popstack(ref List<IEnumerable<byte>> stack)
1023         {
1024             int nCount = stack.Count;
1025             if (nCount == 0)
1026                 throw new StackMachineException("popstack() : stack empty");
1027             stack.RemoveAt(nCount - 1);
1028         }
1029
1030         /// <summary>
1031         /// Get element at specified stack depth
1032         /// </summary>
1033         /// <param name="stack">Stack reference</param>
1034         /// <param name="nDepth">Depth</param>
1035         /// <returns>Byte sequence</returns>
1036         static IEnumerable<byte> stacktop(ref List<IEnumerable<byte>> stack, int nDepth)
1037         {
1038             int nStackElement = stack.Count + nDepth;
1039
1040             if (nDepth >= 0)
1041             {
1042                 StringBuilder sb = new StringBuilder();
1043                 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
1044
1045                 throw new StackMachineException(sb.ToString());
1046             }
1047
1048             if (nStackElement < 0)
1049             {
1050                 StringBuilder sb = new StringBuilder();
1051                 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
1052
1053                 throw new StackMachineException(sb.ToString());
1054             }
1055
1056             return stack[nStackElement];
1057         }
1058
1059         /// <summary>
1060         /// Cast argument to boolean value
1061         /// </summary>
1062         /// <param name="value">Some byte sequence</param>
1063         /// <returns></returns>
1064         private static bool CastToBool(IEnumerable<byte> arg)
1065         {
1066             byte[] value = arg.ToArray();
1067
1068             for (var i = 0; i < value.Length; i++)
1069             {
1070                 if (value[i] != 0)
1071                 {
1072                     // Can be negative zero
1073                     if (i == value.Length - 1 && value[i] == 0x80)
1074                     {
1075                         return false;
1076                     }
1077
1078                     return true;
1079                 }
1080             }
1081
1082             return false;
1083         }
1084
1085         /// <summary>
1086         /// Cast argument to integer value
1087         /// </summary>
1088         /// <param name="value"></param>
1089         /// <returns></returns>
1090         private static BigInteger CastToBigInteger(IEnumerable<byte> value)
1091         {
1092             if (value.Count() > 4)
1093             {
1094                 throw new StackMachineException("CastToBigInteger() : overflow");
1095             }
1096
1097             return new BigInteger(value.ToArray());
1098         }
1099
1100         /// <summary>
1101         /// Execution of script
1102         /// </summary>
1103         /// <param name="stack"></param>
1104         /// <param name="script">Script to execute</param>
1105         /// <param name="txTo">Transaction instance</param>
1106         /// <param name="nIn">Input number</param>
1107         /// <param name="flags">Signature checking flags</param>
1108         /// <param name="nHashType">Hash type flag</param>
1109         /// <returns></returns>
1110         static bool EvalScript(ref List<IEnumerable<byte>> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
1111         {
1112             instruction opcode;
1113
1114             ByteQueue CodeQueue = script.GetByteQUeue();
1115
1116             List<bool> vfExec = new List<bool>();
1117             List<IEnumerable<byte>> altStack = new List<IEnumerable<byte>>();
1118
1119             byte[] falseBytes = new byte[0];
1120             byte[] trueBytes = new byte[] { 0x01 };
1121
1122             if (script.Bytes.Count() > 10000)
1123             {
1124                 return false; // Size limit failed
1125             }
1126
1127             int nOpCount = 0;
1128             int nCodeHashBegin = 0;
1129
1130             IEnumerable<byte> pushArg;
1131
1132             while (GetOp(ref CodeQueue, out opcode, out pushArg)) // Read instructions
1133             {
1134                 bool fExec = vfExec.IndexOf(false) != -1;
1135
1136                 if (pushArg.Count() > 520)
1137                 {
1138                     return false; // Script element size limit failed
1139                 }
1140
1141                 if (opcode > instruction.OP_16 && ++nOpCount > 201)
1142                 {
1143                     return false;
1144                 }
1145
1146                 if (fExec && 0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
1147                 {
1148                     stack.Add(pushArg); // Push argument to stack
1149                 }
1150                 else if (fExec || (instruction.OP_IF <= opcode && opcode <= instruction.OP_ENDIF))
1151                     switch (opcode)
1152                     {
1153                         //
1154                         // Disabled opcodes
1155                         //
1156                         case instruction.OP_CAT:
1157                         case instruction.OP_SUBSTR:
1158                         case instruction.OP_LEFT:
1159                         case instruction.OP_RIGHT:
1160                         case instruction.OP_INVERT:
1161                         case instruction.OP_AND:
1162                         case instruction.OP_OR:
1163                         case instruction.OP_XOR:
1164                         case instruction.OP_2MUL:
1165                         case instruction.OP_2DIV:
1166                         case instruction.OP_MUL:
1167                         case instruction.OP_DIV:
1168                         case instruction.OP_MOD:
1169                         case instruction.OP_LSHIFT:
1170                         case instruction.OP_RSHIFT:
1171                             return false;
1172
1173                         //
1174                         // Push integer instructions
1175                         //
1176                         case instruction.OP_1NEGATE:
1177                         case instruction.OP_1:
1178                         case instruction.OP_2:
1179                         case instruction.OP_3:
1180                         case instruction.OP_4:
1181                         case instruction.OP_5:
1182                         case instruction.OP_6:
1183                         case instruction.OP_7:
1184                         case instruction.OP_8:
1185                         case instruction.OP_9:
1186                         case instruction.OP_10:
1187                         case instruction.OP_11:
1188                         case instruction.OP_12:
1189                         case instruction.OP_13:
1190                         case instruction.OP_14:
1191                         case instruction.OP_15:
1192                         case instruction.OP_16:
1193                             {
1194                                 // ( -- value)
1195                                 BigInteger bn = DecodeOP_N(opcode, true);
1196                                 stack.Add(bn.ToByteArray());
1197                             }
1198                             break;
1199
1200                         //
1201                         // Extension
1202                         //
1203                         case instruction.OP_NOP:
1204                         case instruction.OP_NOP1:
1205                         case instruction.OP_NOP2:
1206                         case instruction.OP_NOP3:
1207                         case instruction.OP_NOP4:
1208                         case instruction.OP_NOP5:
1209                         case instruction.OP_NOP6:
1210                         case instruction.OP_NOP7:
1211                         case instruction.OP_NOP8:
1212                         case instruction.OP_NOP9:
1213                         case instruction.OP_NOP10:
1214                             {
1215                                 // Just do nothing
1216                             }
1217                             break;
1218
1219                         //
1220                         // Control
1221                         //
1222                         case instruction.OP_IF:
1223                         case instruction.OP_NOTIF:
1224                             {
1225                                 // <expression> if [statements] [else [statements]] endif
1226                                 bool fValue = false;
1227                                 if (fExec)
1228                                 {
1229                                     if (stack.Count() < 1)
1230                                     {
1231                                         return false;
1232                                     }
1233                                     IEnumerable<byte> vch = stacktop(ref stack, -1);
1234                                     fValue = CastToBool(vch);
1235                                     if (opcode == instruction.OP_NOTIF)
1236                                     {
1237                                         fValue = !fValue;
1238                                     }
1239                                     popstack(ref stack);
1240                                 }
1241                                 vfExec.Add(fValue);
1242                             }
1243                             break;
1244
1245                         case instruction.OP_ELSE:
1246                             {
1247                                 int nExecCount = vfExec.Count();
1248                                 if (nExecCount == 0)
1249                                 {
1250                                     return false;
1251                                 }
1252                                 vfExec[nExecCount - 1] = !vfExec[nExecCount - 1];
1253                             }
1254                             break;
1255
1256                         case instruction.OP_ENDIF:
1257                             {
1258                                 int nExecCount = vfExec.Count();
1259                                 if (nExecCount == 0)
1260                                 {
1261                                     return false;
1262                                 }
1263                                 vfExec.RemoveAt(nExecCount - 1);
1264                             }
1265                             break;
1266
1267                         case instruction.OP_VERIFY:
1268                             {
1269                                 // (true -- ) or
1270                                 // (false -- false) and return
1271                                 if (stack.Count() < 1)
1272                                 {
1273                                     return false;
1274                                 }
1275
1276                                 bool fValue = CastToBool(stacktop(ref stack, -1));
1277                                 if (fValue)
1278                                 {
1279                                     popstack(ref stack);
1280                                 }
1281                                 else
1282                                 {
1283                                     return false;
1284                                 }
1285                             }
1286                             break;
1287
1288                         case instruction.OP_RETURN:
1289                             {
1290                                 return false;
1291                             }
1292
1293                         //
1294                         // Stack ops
1295                         //
1296                         case instruction.OP_TOALTSTACK:
1297                             {
1298                                 if (stack.Count() < 1)
1299                                 {
1300                                     return false;
1301                                 }
1302                                 altStack.Add(stacktop(ref stack, -1));
1303                                 popstack(ref stack);
1304                             }
1305                             break;
1306
1307                         case instruction.OP_FROMALTSTACK:
1308                             {
1309                                 if (altStack.Count() < 1)
1310                                 {
1311                                     return false;
1312                                 }
1313                                 stack.Add(stacktop(ref stack, -1));
1314                                 popstack(ref altStack);
1315                             }
1316                             break;
1317
1318                         case instruction.OP_2DROP:
1319                             {
1320                                 // (x1 x2 -- )
1321                                 if (stack.Count() < 2)
1322                                 {
1323                                     return false;
1324                                 }
1325                                 popstack(ref stack);
1326                                 popstack(ref stack);
1327                             }
1328                             break;
1329
1330                         case instruction.OP_2DUP:
1331                             {
1332                                 // (x1 x2 -- x1 x2 x1 x2)
1333                                 if (stack.Count() < 2)
1334                                 {
1335                                     return false;
1336                                 }
1337                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1338                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1339                                 stack.Add(vch1);
1340                                 stack.Add(vch2);
1341                             }
1342                             break;
1343
1344                         case instruction.OP_3DUP:
1345                             {
1346                                 // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
1347                                 if (stack.Count() < 3)
1348                                 {
1349                                     return false;
1350                                 }
1351                                 IEnumerable<byte> vch1 = stacktop(ref stack, -3);
1352                                 IEnumerable<byte> vch2 = stacktop(ref stack, -2);
1353                                 IEnumerable<byte> vch3 = stacktop(ref stack, -1);
1354                                 stack.Add(vch1);
1355                                 stack.Add(vch2);
1356                                 stack.Add(vch3);
1357                             }
1358                             break;
1359
1360                         case instruction.OP_2OVER:
1361                             {
1362                                 // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
1363                                 if (stack.Count() < 4)
1364                                 {
1365                                     return false;
1366                                 }
1367                                 IEnumerable<byte> vch1 = stacktop(ref stack, -4);
1368                                 IEnumerable<byte> vch2 = stacktop(ref stack, -3);
1369                                 stack.Add(vch1);
1370                                 stack.Add(vch2);
1371                             }
1372                             break;
1373
1374                         case instruction.OP_2ROT:
1375                             {
1376                                 int nStackDepth = stack.Count();
1377                                 // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
1378                                 if (nStackDepth < 6)
1379                                 {
1380                                     return false;
1381                                 }
1382                                 IEnumerable<byte> vch1 = stacktop(ref stack, -6);
1383                                 IEnumerable<byte> vch2 = stacktop(ref stack, -5);
1384                                 stack.RemoveRange(nStackDepth - 6, 2);
1385                                 stack.Add(vch1);
1386                                 stack.Add(vch2);
1387                             }
1388                             break;
1389
1390                         case instruction.OP_2SWAP:
1391                             {
1392                                 // (x1 x2 x3 x4 -- x3 x4 x1 x2)
1393                                 int nStackDepth = stack.Count();
1394                                 if (nStackDepth < 4)
1395                                 {
1396                                     return false;
1397                                 }
1398                                 stack.Swap(nStackDepth - 4, nStackDepth - 2);
1399                                 stack.Swap(nStackDepth - 3, nStackDepth - 1);
1400                             }
1401                             break;
1402
1403                         case instruction.OP_IFDUP:
1404                             {
1405                                 // (x - 0 | x x)
1406                                 if (stack.Count() < 1)
1407                                 {
1408                                     return false;
1409                                 }
1410
1411                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1412
1413                                 if (CastToBool(vch))
1414                                 {
1415                                     stack.Add(vch);
1416                                 }
1417                             }
1418                             break;
1419
1420                         case instruction.OP_DEPTH:
1421                             {
1422                                 // -- stacksize
1423                                 BigInteger bn = new BigInteger((ushort)stack.Count());
1424                                 stack.Add(bn.ToByteArray());
1425                             }
1426                             break;
1427
1428                         case instruction.OP_DROP:
1429                             {
1430                                 // (x -- )
1431                                 if (stack.Count() < 1)
1432                                 {
1433                                     return false;
1434                                 }
1435
1436                                 popstack(ref stack);
1437                             }
1438                             break;
1439
1440                         case instruction.OP_DUP:
1441                             {
1442                                 // (x -- x x)
1443                                 if (stack.Count() < 1)
1444                                 {
1445                                     return false;
1446                                 }
1447
1448                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1449                                 stack.Add(vch);
1450                             }
1451                             break;
1452
1453                         case instruction.OP_NIP:
1454                             {
1455                                 // (x1 x2 -- x2)
1456                                 int nStackDepth = stack.Count();
1457                                 if (nStackDepth < 2)
1458                                 {
1459                                     return false;
1460                                 }
1461
1462                                 stack.RemoveAt(nStackDepth - 2);
1463                             }
1464                             break;
1465
1466                         case instruction.OP_OVER:
1467                             {
1468                                 // (x1 x2 -- x1 x2 x1)
1469                                 if (stack.Count() < 2)
1470                                 {
1471                                     return false;
1472                                 }
1473
1474                                 IEnumerable<byte> vch = stacktop(ref stack, -2);
1475                                 stack.Add(vch);
1476                             }
1477                             break;
1478
1479                         case instruction.OP_PICK:
1480                         case instruction.OP_ROLL:
1481                             {
1482                                 // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
1483                                 // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
1484
1485                                 int nStackDepth = stack.Count();
1486                                 if (nStackDepth < 2)
1487                                 {
1488                                     return false;
1489                                 }
1490
1491                                 int n = (int)CastToBigInteger(stacktop(ref stack, -1));
1492                                 popstack(ref stack);
1493
1494                                 if (n < 0 || n >= stack.Count())
1495                                 {
1496                                     return false;
1497                                 }
1498
1499                                 IEnumerable<byte> vch = stacktop(ref stack, -n - 1);
1500                                 if (opcode == instruction.OP_ROLL)
1501                                 {
1502                                     stack.RemoveAt(nStackDepth - n - 1);
1503                                 }
1504
1505                                 stack.Add(vch);
1506                             }
1507                             break;
1508
1509                         case instruction.OP_ROT:
1510                             {
1511                                 // (x1 x2 x3 -- x2 x3 x1)
1512                                 //  x2 x1 x3  after first swap
1513                                 //  x2 x3 x1  after second swap
1514                                 int nStackDepth = stack.Count();
1515                                 if (nStackDepth < 3)
1516                                 {
1517                                     return false;
1518                                 }
1519                                 stack.Swap(nStackDepth - 3, nStackDepth - 2);
1520                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1521
1522                             }
1523                             break;
1524
1525                         case instruction.OP_SWAP:
1526                             {
1527                                 // (x1 x2 -- x2 x1)
1528                                 int nStackDepth = stack.Count();
1529                                 if (nStackDepth < 2)
1530                                 {
1531                                     return false;
1532                                 }
1533                                 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1534                             }
1535                             break;
1536
1537                         case instruction.OP_TUCK:
1538                             {
1539                                 // (x1 x2 -- x2 x1 x2)
1540                                 int nStackDepth = stack.Count();
1541                                 if (nStackDepth < 2)
1542                                 {
1543                                     return false;
1544                                 }
1545                                 IEnumerable<byte> vch = stacktop(ref stack, -1);
1546                                 stack.Insert(nStackDepth - 2, vch);
1547                             }
1548                             break;
1549
1550
1551                         case instruction.OP_SIZE:
1552                             {
1553                                 // (in -- in size)
1554                                 if (stack.Count() < 1)
1555                                 {
1556                                     return false;
1557                                 }
1558
1559                                 BigInteger bnSize = new BigInteger((ushort)stacktop(ref stack, -1).Count());
1560                                 stack.Add(bnSize.ToByteArray());
1561                             }
1562                             break;
1563
1564
1565                         //
1566                         // Bitwise logic
1567                         //
1568                         case instruction.OP_EQUAL:
1569                         case instruction.OP_EQUALVERIFY:
1570                             //case instruction.OP_NOTEQUAL: // use OP_NUMNOTEQUAL
1571                             {
1572                                 // (x1 x2 - bool)
1573                                 if (stack.Count() < 2)
1574                                 {
1575                                     return false;
1576                                 }
1577
1578                                 IEnumerable<byte> vch1 = stacktop(ref stack, -2);
1579                                 IEnumerable<byte> vch2 = stacktop(ref stack, -1);
1580                                 bool fEqual = (vch1 == vch2);
1581                                 // OP_NOTEQUAL is disabled because it would be too easy to say
1582                                 // something like n != 1 and have some wiseguy pass in 1 with extra
1583                                 // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
1584                                 //if (opcode == instruction.OP_NOTEQUAL)
1585                                 //    fEqual = !fEqual;
1586                                 popstack(ref stack);
1587                                 popstack(ref stack);
1588                                 stack.Add(fEqual ? trueBytes : falseBytes);
1589
1590                                 if (opcode == instruction.OP_EQUALVERIFY)
1591                                 {
1592                                     if (fEqual)
1593                                     {
1594                                         popstack(ref stack);
1595                                     }
1596                                     else
1597                                     {
1598                                         return false;
1599                                     }
1600                                 }
1601                             }
1602                             break;
1603
1604
1605                         //
1606                         // Numeric
1607                         //
1608                         case instruction.OP_1ADD:
1609                         case instruction.OP_1SUB:
1610                         case instruction.OP_NEGATE:
1611                         case instruction.OP_ABS:
1612                         case instruction.OP_NOT:
1613                         case instruction.OP_0NOTEQUAL:
1614                             {
1615                                 // (in -- out)
1616                                 if (stack.Count() < 1)
1617                                 {
1618                                     return false;
1619                                 }
1620
1621                                 BigInteger bn = CastToBigInteger(stacktop(ref stack, -1));
1622                                 switch (opcode)
1623                                 {
1624                                     case instruction.OP_1ADD:
1625                                         bn = bn + 1;
1626                                         break;
1627                                     case instruction.OP_1SUB:
1628                                         bn = bn - 1;
1629                                         break;
1630                                     case instruction.OP_NEGATE:
1631                                         bn = -bn;
1632                                         break;
1633                                     case instruction.OP_ABS:
1634                                         bn = BigInteger.Abs(bn);
1635                                         break;
1636                                     case instruction.OP_NOT:
1637                                         bn = bn == 0 ? 1 : 0;
1638                                         break;
1639                                     case instruction.OP_0NOTEQUAL:
1640                                         bn = bn != 0 ? 1 : 0;
1641                                         break;
1642                                 }
1643
1644                                 popstack(ref stack);
1645                                 stack.Add(bn.ToByteArray());
1646                             }
1647                             break;
1648
1649                         case instruction.OP_ADD:
1650                         case instruction.OP_SUB:
1651                         case instruction.OP_BOOLAND:
1652                         case instruction.OP_BOOLOR:
1653                         case instruction.OP_NUMEQUAL:
1654                         case instruction.OP_NUMEQUALVERIFY:
1655                         case instruction.OP_NUMNOTEQUAL:
1656                         case instruction.OP_LESSTHAN:
1657                         case instruction.OP_GREATERTHAN:
1658                         case instruction.OP_LESSTHANOREQUAL:
1659                         case instruction.OP_GREATERTHANOREQUAL:
1660                         case instruction.OP_MIN:
1661                         case instruction.OP_MAX:
1662                             {
1663                                 // (x1 x2 -- out)
1664                                 if (stack.Count() < 2)
1665                                 {
1666                                     return false;
1667                                 }
1668
1669                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -2));
1670                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -1));
1671                                 BigInteger bn = 0;
1672
1673                                 switch (opcode)
1674                                 {
1675                                     case instruction.OP_ADD:
1676                                         bn = bn1 + bn2;
1677                                         break;
1678                                     case instruction.OP_SUB:
1679                                         bn = bn1 - bn2;
1680                                         break;
1681                                     case instruction.OP_BOOLAND:
1682                                         bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1683                                         break;
1684                                     case instruction.OP_BOOLOR:
1685                                         bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1686                                         break;
1687                                     case instruction.OP_NUMEQUAL:
1688                                         bn = (bn1 == bn2) ? 1 : 0;
1689                                         break;
1690                                     case instruction.OP_NUMEQUALVERIFY:
1691                                         bn = (bn1 == bn2) ? 1 : 0;
1692                                         break;
1693                                     case instruction.OP_NUMNOTEQUAL:
1694                                         bn = (bn1 != bn2) ? 1 : 0;
1695                                         break;
1696                                     case instruction.OP_LESSTHAN:
1697                                         bn = (bn1 < bn2) ? 1 : 0;
1698                                         break;
1699                                     case instruction.OP_GREATERTHAN:
1700                                         bn = (bn1 > bn2) ? 1 : 0;
1701                                         break;
1702                                     case instruction.OP_LESSTHANOREQUAL:
1703                                         bn = (bn1 <= bn2) ? 1 : 0;
1704                                         break;
1705                                     case instruction.OP_GREATERTHANOREQUAL:
1706                                         bn = (bn1 >= bn2) ? 1 : 0;
1707                                         break;
1708                                     case instruction.OP_MIN:
1709                                         bn = (bn1 < bn2 ? bn1 : bn2);
1710                                         break;
1711                                     case instruction.OP_MAX:
1712                                         bn = (bn1 > bn2 ? bn1 : bn2);
1713                                         break;
1714                                 }
1715
1716                                 popstack(ref stack);
1717                                 popstack(ref stack);
1718                                 stack.Add(bn.ToByteArray());
1719
1720                                 if (opcode == instruction.OP_NUMEQUALVERIFY)
1721                                 {
1722                                     if (CastToBool(stacktop(ref stack, -1)))
1723                                     {
1724                                         popstack(ref stack);
1725                                     }
1726                                     else
1727                                     {
1728                                         return false;
1729                                     }
1730                                 }
1731                             }
1732                             break;
1733
1734                         case instruction.OP_WITHIN:
1735                             {
1736                                 // (x min max -- out)
1737                                 if (stack.Count() < 3)
1738                                     return false;
1739                                 BigInteger bn1 = CastToBigInteger(stacktop(ref stack, -3));
1740                                 BigInteger bn2 = CastToBigInteger(stacktop(ref stack, -2));
1741                                 BigInteger bn3 = CastToBigInteger(stacktop(ref stack, -1));
1742                                 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1743                                 popstack(ref stack);
1744                                 popstack(ref stack);
1745                                 popstack(ref stack);
1746                                 stack.Add(fValue ? trueBytes : falseBytes);
1747                             }
1748                             break;
1749
1750                         //
1751                         // Crypto
1752                         //
1753                         case instruction.OP_RIPEMD160:
1754                         case instruction.OP_SHA1:
1755                         case instruction.OP_SHA256:
1756                         case instruction.OP_HASH160:
1757                         case instruction.OP_HASH256:
1758                             {
1759                                 // (in -- hash)
1760                                 if (stack.Count() < 1)
1761                                 {
1762                                     return false;
1763                                 }
1764                                 Hash hash = null;
1765                                 IEnumerable<byte> data = stacktop(ref stack, -1);
1766
1767                                 switch (opcode)
1768                                 {
1769                                     case instruction.OP_HASH160:
1770                                         hash = Hash160.Compute160(data);
1771                                         break;
1772                                     case instruction.OP_HASH256:
1773                                         hash = Hash256.Compute256(data);
1774                                         break;
1775                                     case instruction.OP_SHA1:
1776                                         hash = SHA1.Compute1(data);
1777                                         break;
1778                                     case instruction.OP_SHA256:
1779                                         hash = SHA256.Compute256(data);
1780                                         break;
1781                                     case instruction.OP_RIPEMD160:
1782                                         hash = RIPEMD160.Compute160(data);
1783                                         break;
1784                                 }
1785                                 popstack(ref stack);
1786                                 stack.Add(hash.hashBytes);
1787                             }
1788                             break;
1789
1790                         case instruction.OP_CODESEPARATOR:
1791                             {
1792                                 // Hash starts after the code separator
1793                                 nCodeHashBegin = CodeQueue.CurrentIndex;
1794                             }
1795                             break;
1796
1797                         case instruction.OP_CHECKSIG:
1798                         case instruction.OP_CHECKSIGVERIFY:
1799                             {
1800                                 // (sig pubkey -- bool)
1801                                 if (stack.Count() < 2)
1802                                 {
1803                                     return false;
1804                                 }
1805
1806                                 IList<byte> sigBytes = stacktop(ref stack, -2).ToList();
1807                                 IList<byte> pubkeyBytes = stacktop(ref stack, -1).ToList();
1808
1809                                 // Subset of script starting at the most recent codeseparator
1810                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1811
1812                                 // There's no way for a signature to sign itself
1813                                 scriptCode.RemovePattern(sigBytes);
1814
1815                                 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes.ToList(), flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1816
1817                                 popstack(ref stack);
1818                                 popstack(ref stack);
1819                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1820                                 if (opcode == instruction.OP_CHECKSIGVERIFY)
1821                                 {
1822                                     if (fSuccess)
1823                                     {
1824                                         popstack(ref stack);
1825                                     }
1826                                     else
1827                                     {
1828                                         return false;
1829                                     }
1830                                 }
1831                             }
1832                             break;
1833
1834                         case instruction.OP_CHECKMULTISIG:
1835                         case instruction.OP_CHECKMULTISIGVERIFY:
1836                             {
1837                                 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1838
1839                                 int i = 1;
1840                                 if (stack.Count() < i)
1841                                 {
1842                                     return false;
1843                                 }
1844
1845                                 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1846                                 if (nKeysCount < 0 || nKeysCount > 20)
1847                                 {
1848                                     return false;
1849                                 }
1850                                 nOpCount += nKeysCount;
1851                                 if (nOpCount > 201)
1852                                 {
1853                                     return false;
1854                                 }
1855                                 int ikey = ++i;
1856                                 i += nKeysCount;
1857                                 if (stack.Count() < i)
1858                                 {
1859                                     return false;
1860                                 }
1861
1862                                 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1863                                 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1864                                 {
1865                                     return false;
1866                                 }
1867                                 int isig = ++i;
1868                                 i += nSigsCount;
1869                                 if (stack.Count() < i)
1870                                 {
1871                                     return false;
1872                                 }
1873
1874                                 // Subset of script starting at the most recent codeseparator
1875                                 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1876
1877                                 // There is no way for a signature to sign itself, so we need to drop the signatures
1878                                 for (int k = 0; k < nSigsCount; k++)
1879                                 {
1880                                     IEnumerable<byte> vchSig = stacktop(ref stack, -isig - k);
1881                                     scriptCode.RemovePattern(vchSig.ToList());
1882                                 }
1883
1884                                 bool fSuccess = true;
1885                                 while (fSuccess && nSigsCount > 0)
1886                                 {
1887                                     IList<byte> sigBytes = stacktop(ref stack, -isig).ToList();
1888                                     IList<byte> pubKeyBytes = stacktop(ref stack, -ikey).ToList();
1889
1890                                     // Check signature
1891                                     bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes.ToList(), flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1892
1893                                     if (fOk)
1894                                     {
1895                                         isig++;
1896                                         nSigsCount--;
1897                                     }
1898                                     ikey++;
1899                                     nKeysCount--;
1900
1901                                     // If there are more signatures left than keys left,
1902                                     // then too many signatures have failed
1903                                     if (nSigsCount > nKeysCount)
1904                                     {
1905                                         fSuccess = false;
1906                                     }
1907                                 }
1908
1909                                 while (i-- > 1)
1910                                 {
1911                                     popstack(ref stack);
1912                                 }
1913
1914                                 // A bug causes CHECKMULTISIG to consume one extra argument
1915                                 // whose contents were not checked in any way.
1916                                 //
1917                                 // Unfortunately this is a potential source of mutability,
1918                                 // so optionally verify it is exactly equal to zero prior
1919                                 // to removing it from the stack.
1920                                 if (stack.Count() < 1)
1921                                 {
1922                                     return false;
1923                                 }
1924                                 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1925                                 {
1926                                     return false; // CHECKMULTISIG dummy argument not null
1927                                 }
1928                                 popstack(ref stack);
1929
1930                                 stack.Add(fSuccess ? trueBytes : falseBytes);
1931
1932                                 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1933                                 {
1934                                     if (fSuccess)
1935                                     {
1936                                         popstack(ref stack);
1937                                     }
1938                                     else
1939                                     {
1940                                         return false;
1941                                     }
1942                                 }
1943                             }
1944                             break;
1945
1946                         default:
1947                             return false;
1948                     }
1949
1950                 // Size limits
1951                 if (stack.Count() + altStack.Count() > 1000)
1952                 {
1953                     return false;
1954                 }
1955             }
1956
1957
1958             if (vfExec.Count() == 0)
1959             {
1960                 return false;
1961             }
1962
1963             return true;
1964         }
1965
1966
1967         static bool IsCanonicalPubKey(IList<byte> pubKeyBytes, int flags)
1968         {
1969             if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1970                 return true;
1971
1972             if (pubKeyBytes.Count < 33)
1973                 return false;  // Non-canonical public key: too short
1974             if (pubKeyBytes[0] == 0x04)
1975             {
1976                 if (pubKeyBytes.Count != 65)
1977                     return false; // Non-canonical public key: invalid length for uncompressed key
1978             }
1979             else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1980             {
1981                 if (pubKeyBytes.Count != 33)
1982                     return false; // Non-canonical public key: invalid length for compressed key
1983             }
1984             else
1985             {
1986                 return false; // Non-canonical public key: compressed nor uncompressed
1987             }
1988             return true;
1989         }
1990
1991         static bool IsCanonicalSignature(IList<byte> sigBytes, int flags)
1992         {
1993             // STUB
1994
1995             return true;
1996         }
1997
1998         /// <summary>
1999         /// Check signature.
2000         /// </summary>
2001         /// <param name="sigBytes">Signature</param>
2002         /// <param name="pubkeyBytes">Public key</param>
2003         /// <param name="script">Spending script</param>
2004         /// <param name="txTo">CTransaction instance</param>
2005         /// <param name="nIn">Input number</param>
2006         /// <param name="nHashType">Hashing type flag</param>
2007         /// <param name="flags">Signature checking flags</param>
2008         /// <returns></returns>
2009         static bool CheckSig(IList<byte> sigBytes, IList<byte> pubkeyBytes, CScript script, CTransaction txTo, int nIn, int nHashType, int flags)
2010         {
2011             CPubKey pubkey;
2012
2013             try
2014             {
2015                 // Trying to initialize the public key instance
2016
2017                 pubkey = new CPubKey(pubkeyBytes);
2018             }
2019             catch (Exception)
2020             {
2021                 // Exception occurred while initializing the public key
2022
2023                 return false;
2024             }
2025
2026             if (!pubkey.IsValid)
2027             {
2028                 return false;
2029             }
2030
2031             if (sigBytes.Count == 0)
2032             {
2033                 return false;
2034             }
2035
2036             // Hash type is one byte tacked on to the end of the signature
2037             if (nHashType == 0)
2038             {
2039                 nHashType = sigBytes.Last();
2040             }
2041             else if (nHashType != sigBytes.Last())
2042             {
2043                 return false;
2044             }
2045
2046             // Remove hash type
2047             sigBytes.RemoveAt(sigBytes.Count - 1);
2048
2049             Hash256 sighash = SignatureHash(script, txTo, nIn, nHashType);
2050
2051             if (!pubkey.VerifySignature(sighash, sigBytes))
2052             {
2053                 return false;
2054             }
2055
2056             return true;
2057         }
2058     };
2059 }