3 * This program is free software: you can redistribute it and/or modify
4 * it under the terms of the GNU Affero General Public License as
5 * published by the Free Software Foundation, either version 3 of the
6 * License, or (at your option) any later version.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU Affero General Public License for more details.
13 * You should have received a copy of the GNU Affero General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 using System.Collections.Generic;
20 using System.Numerics;
26 /// Script instructions
28 public enum instruction
70 OP_FROMALTSTACK = 0x6c,
102 OP_EQUALVERIFY = 0x88,
127 OP_NUMEQUALVERIFY = 0x9d,
128 OP_NUMNOTEQUAL = 0x9e,
130 OP_GREATERTHAN = 0xa0,
131 OP_LESSTHANOREQUAL = 0xa1,
132 OP_GREATERTHANOREQUAL = 0xa2,
144 OP_CODESEPARATOR = 0xab,
146 OP_CHECKSIGVERIFY = 0xad,
147 OP_CHECKMULTISIG = 0xae,
148 OP_CHECKMULTISIGVERIFY = 0xaf,
162 // template matching params
164 OP_SMALLINTEGER = 0xfa,
166 OP_PUBKEYHASH = 0xfd,
169 OP_INVALIDOPCODE = 0xff,
173 /// Transaction output types.
175 public enum txnouttype
179 // 'standard' transaction types:
188 /// Signature hash types/flags
195 SIGHASH_ANYONECANPAY = 0x80,
198 /** Script verification flags */
199 public enum scriptflag
201 SCRIPT_VERIFY_NONE = 0,
202 SCRIPT_VERIFY_P2SH = (1 << 0), // evaluate P2SH (BIP16) subscripts
203 SCRIPT_VERIFY_STRICTENC = (1 << 1), // enforce strict conformance to DER and SEC2 for signatures and pubkeys
204 SCRIPT_VERIFY_LOW_S = (1 << 2), // enforce low S values in signatures (depends on STRICTENC)
205 SCRIPT_VERIFY_NOCACHE = (1 << 3), // do not store results in signature cache (but do query it)
206 SCRIPT_VERIFY_NULLDUMMY = (1 << 4), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
209 public static class ScriptCode
211 public static string GetTxnOutputType(txnouttype t)
215 case txnouttype.TX_NONSTANDARD: return "nonstandard";
216 case txnouttype.TX_PUBKEY: return "pubkey";
217 case txnouttype.TX_PUBKEYHASH: return "pubkeyhash";
218 case txnouttype.TX_SCRIPTHASH: return "scripthash";
219 case txnouttype.TX_MULTISIG: return "multisig";
220 case txnouttype.TX_NULL_DATA: return "nulldata";
226 /// Get the name of instruction
228 /// <param name="opcode">Instruction</param>
229 /// <returns>Instruction name</returns>
230 public static string GetOpName(instruction opcode)
232 if (opcode == instruction.OP_0) // OP_0 and OP_FALSE are synonyms
234 if (opcode == instruction.OP_1) // OP_1 and OP_TRUE are synonyms
237 return Enum.GetName(typeof(instruction), opcode);
241 /// Get next instruction from list of bytes and extract push arguments if there are some.
243 /// <param name="codeBytes">ByteQueue reference.</param>
244 /// <param name="opcodeRet">Found instruction.</param>
245 /// <param name="bytesRet">IEnumerable out param which is used to get the push arguments.</param>
246 /// <returns>Result of operation</returns>
247 public static bool GetOp(ref ByteQueue codeBytes, out instruction opcodeRet, out byte[] bytesRet)
249 bytesRet = new byte[0];
250 opcodeRet = instruction.OP_INVALIDOPCODE;
257 opcode = (instruction)codeBytes.Get();
259 catch (ByteQueueException)
261 // No instruction found there
266 if (opcode <= instruction.OP_PUSHDATA4)
268 byte[] szBytes = new byte[4] { 0, 0, 0, 0 }; // Zero length
272 if (opcode < instruction.OP_PUSHDATA1)
274 // Zero value instructions (OP_0, OP_FALSE)
275 szBytes[3] = (byte)opcode;
277 else if (opcode == instruction.OP_PUSHDATA1)
279 // The next byte contains the number of bytes to be pushed onto the stack,
280 // i.e. you have something like OP_PUSHDATA1 0x01 [0x5a]
281 szBytes[3] = codeBytes.Get();
283 else if (opcode == instruction.OP_PUSHDATA2)
285 // The next two bytes contain the number of bytes to be pushed onto the stack,
286 // i.e. now your operation will seem like this: OP_PUSHDATA2 0x00 0x01 [0x5a]
287 codeBytes.Get(2).CopyTo(szBytes, 2);
289 else if (opcode == instruction.OP_PUSHDATA4)
291 // The next four bytes contain the number of bytes to be pushed onto the stack,
292 // OP_PUSHDATA4 0x00 0x00 0x00 0x01 [0x5a]
293 szBytes = codeBytes.Get(4);
296 catch (ByteQueueException)
298 // Unable to read operand length
302 int nSize = (int)Interop.BEBytesToUInt32(szBytes);
306 // If nSize is greater than zero then there is some data available
309 // Read found number of bytes into list of OP_PUSHDATAn arguments.
310 bytesRet = codeBytes.Get(nSize);
312 catch (ByteQueueException)
314 // Unable to read data
326 /// Convert value bytes into readable representation.
328 /// 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.
330 /// <param name="bytes">Collection of value bytes.</param>
331 /// <returns>Formatted value.</returns>
332 public static string ValueString(byte[] bytes)
334 var sb = new StringBuilder();
336 if (bytes.Length <= 4)
338 sb.Append(Interop.BEBytesToUInt32(bytes));
342 return Interop.ToHex(bytes);
345 return sb.ToString();
349 /// Convert list of stack items into human readable representation.
351 /// <param name="stackList">List of stack items.</param>
352 /// <returns>Formatted value.</returns>
353 public static string StackString(IList<byte[]> stackList)
355 var sb = new StringBuilder();
356 foreach (var bytes in stackList)
358 sb.Append(ValueString(bytes));
361 return sb.ToString();
365 /// Decode instruction to integer value
367 /// <param name="opcode">Small integer instruction (OP_1_NEGATE and OP_0 - OP_16)</param>
368 /// <returns>Small integer</returns>
369 public static int DecodeOP_N(instruction opcode, bool AllowNegate = false)
371 if (AllowNegate && opcode == instruction.OP_1NEGATE)
376 if (opcode == instruction.OP_0)
381 // Only OP_n instructions are supported, throw exception otherwise.
382 if (opcode < instruction.OP_1 || opcode > instruction.OP_16)
384 throw new ArgumentException("Invalid integer instruction.");
387 return (int)opcode - (int)(instruction.OP_1 - 1);
391 /// Converts integer into instruction
393 /// <param name="n">Small integer from the range of -1 up to 16.</param>
394 /// <returns>Corresponding instruction.</returns>
395 public static instruction EncodeOP_N(int n, bool allowNegate = false)
397 if (allowNegate && n == -1)
399 return instruction.OP_1NEGATE;
404 return instruction.OP_0;
407 // The n value must be in the range of 0 to 16.
409 throw new ArgumentException("Invalid integer value.");
410 return (instruction.OP_1 + n - 1);
413 public static int ScriptSigArgsExpected(txnouttype t, IList<byte[]> solutions)
417 case txnouttype.TX_NONSTANDARD:
419 case txnouttype.TX_NULL_DATA:
421 case txnouttype.TX_PUBKEY:
423 case txnouttype.TX_PUBKEYHASH:
425 case txnouttype.TX_MULTISIG:
426 if (solutions.Count < 1 || solutions.First().Length < 1)
428 return solutions.First()[0] + 1;
429 case txnouttype.TX_SCRIPTHASH:
430 return 1; // doesn't include args needed by the script
436 /// Is it a standart type of scriptPubKey?
438 /// <param name="scriptPubKey">CScript instance</param>
439 /// <param name="whichType">utut type</param>
440 /// <returns>Checking result</returns>
441 public static bool IsStandard(CScript scriptPubKey, out txnouttype whichType)
443 IList<byte[]> solutions;
445 if (!Solver(scriptPubKey, out whichType, out solutions))
447 // No solutions found
451 if (whichType == txnouttype.TX_MULTISIG)
453 // Additional verification of OP_CHECKMULTISIG arguments
454 var m = solutions.First()[0];
455 var n = solutions.Last()[0];
457 // Support up to x-of-3 multisig txns as standard
468 return whichType != txnouttype.TX_NONSTANDARD;
472 /// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
474 /// <param name="scriptPubKey">CScript instance</param>
475 /// <param name="typeRet">Output type</param>
476 /// <param name="solutions">Set of solutions</param>
477 /// <returns>Result</returns>
478 public static bool Solver(CScript scriptPubKey, out txnouttype typeRet, out IList<byte[]> solutions)
480 solutions = new List<byte[]>();
482 // There are shortcuts for pay-to-script-hash and pay-to-pubkey-hash, which are more constrained than the other types.
484 // It is always OP_HASH160 20 [20 byte hash] OP_EQUAL
485 if (scriptPubKey.IsPayToScriptHash)
487 typeRet = txnouttype.TX_SCRIPTHASH;
489 // Take 20 bytes with offset of 2 bytes
490 var hashBytes = scriptPubKey.Bytes.Skip(2).Take(20);
491 solutions.Add(hashBytes.ToArray());
496 // It is always OP_DUP OP_HASH160 20 [20 byte hash] OP_EQUALVERIFY OP_CHECKSIG
497 if (scriptPubKey.IsPayToPubKeyHash)
499 typeRet = txnouttype.TX_PUBKEYHASH;
501 // Take 20 bytes with offset of 3 bytes
502 var hashBytes = scriptPubKey.Bytes.Skip(3).Take(20);
503 solutions.Add(hashBytes.ToArray());
508 var templateTuples = new List<Tuple<txnouttype, byte[]>>();
510 // Sender provides pubkey, receiver adds signature
511 // [ECDSA public key] OP_CHECKSIG
513 new Tuple<txnouttype, byte[]>(
514 txnouttype.TX_PUBKEY,
516 (byte)instruction.OP_PUBKEY,
517 (byte)instruction.OP_CHECKSIG
521 // Sender provides N pubkeys, receivers provides M signatures
522 // N [pubkey1] [pubkey2] ... [pubkeyN] M OP_CHECKMULTISIG
523 // Where N and M are small integer instructions (OP1 ... OP_16)
525 new Tuple<txnouttype, byte[]>(
526 txnouttype.TX_MULTISIG,
528 (byte)instruction.OP_SMALLINTEGER,
529 (byte)instruction.OP_PUBKEYS,
530 (byte)instruction.OP_SMALLINTEGER,
531 (byte)instruction.OP_CHECKMULTISIG
535 // Data-carrying output
536 // OP_RETURN [up to 80 bytes of data]
538 new Tuple<txnouttype, byte[]>(
539 txnouttype.TX_NULL_DATA,
541 (byte)instruction.OP_RETURN,
542 (byte)instruction.OP_SMALLDATA
546 // Nonstandard tx output
547 typeRet = txnouttype.TX_NONSTANDARD;
549 foreach (var templateTuple in templateTuples)
551 var script1 = scriptPubKey;
552 var script2 = new CScript(templateTuple.Item2);
554 instruction opcode1, opcode2;
557 var bq1 = script1.GetByteQUeue();
558 var bq2 = script2.GetByteQUeue();
562 int last1 = script1.Bytes.Count() -1;
563 int last2 = script2.Bytes.Count() - 1;
567 if (bq1.CurrentIndex == last1 && bq2.CurrentIndex == last2)
570 typeRet = templateTuple.Item1;
571 if (typeRet == txnouttype.TX_MULTISIG)
573 // Additional checks for TX_MULTISIG:
574 var m = solutions.First().First();
575 var n = solutions.Last().First();
577 if (m < 1 || n < 1 || m > n || solutions.Count - 2 != n)
585 if (!GetOp(ref bq1, out opcode1, out args1))
589 if (!GetOp(ref bq2, out opcode2, out args2))
594 // Template matching instructions:
595 if (opcode2 == instruction.OP_PUBKEYS)
597 while (args1.Count() >= 33 && args1.Count() <= 120)
599 solutions.Add(args1);
600 if (!GetOp(ref bq1, out opcode1, out args1))
605 if (!GetOp(ref bq2, out opcode2, out args2))
609 // Normal situation is to fall through
610 // to other if/else statements
612 if (opcode2 == instruction.OP_PUBKEY)
614 int PubKeyLen = args1.Count();
615 if (PubKeyLen < 33 || PubKeyLen > 120)
619 solutions.Add(args1);
621 else if (opcode2 == instruction.OP_PUBKEYHASH)
623 if (args1.Count() != 20) // hash160 size
627 solutions.Add(args1);
629 else if (opcode2 == instruction.OP_SMALLINTEGER)
631 // Single-byte small integer pushed onto solutions
634 var n = (byte)DecodeOP_N(opcode1);
635 solutions.Add(new byte[] { n });
642 else if (opcode2 == instruction.OP_SMALLDATA)
644 // small pushdata, <= 80 bytes
645 if (args1.Length > 80)
650 else if (opcode1 != opcode2 || !args1.SequenceEqual(args2))
652 // Others must match exactly
659 typeRet = txnouttype.TX_NONSTANDARD;
665 /// Generation of SignatureHash. This method is responsible for removal of transaction metadata. It's necessary signature can't sign itself.
667 /// <param name="script">Spending instructions</param>
668 /// <param name="txTo">Instance of transaction</param>
669 /// <param name="nIn">Input number</param>
670 /// <param name="nHashType">Hash type flag</param>
671 /// <returns></returns>
672 public static Hash256 SignatureHash(CScript script, CTransaction txTo, int nIn, int nHashType)
674 if (nIn >= txTo.vin.Length)
676 var sb = new StringBuilder();
677 sb.AppendFormat("ERROR: SignatureHash() : nIn={0} out of range\n", nIn);
678 throw new ArgumentOutOfRangeException("nIn", sb.ToString());
681 // Init a copy of transaction
682 var txTmp = new CTransaction(txTo);
684 // In case concatenating two scripts ends up with two codeseparators,
685 // or an extra one at the end, this prevents all those possible incompatibilities.
686 script.RemovePattern(new byte[] { (byte)instruction.OP_CODESEPARATOR });
688 // Blank out other inputs' signatures
689 for (int i = 0; i < txTmp.vin.Length; i++)
691 txTmp.vin[i].scriptSig = new CScript();
693 txTmp.vin[nIn].scriptSig = script;
695 // Blank out some of the outputs
696 if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_NONE)
699 txTmp.vout = new CTxOut[0];
701 // Let the others update at will
702 for (int i = 0; i < txTmp.vin.Length; i++)
706 txTmp.vin[i].nSequence = 0;
710 else if ((nHashType & 0x1f) == (int)sigflag.SIGHASH_SINGLE)
712 // Only lock-in the txout payee at same index as txin
714 if (nOut >= txTmp.vout.Length)
716 StringBuilder sb = new StringBuilder();
717 sb.AppendFormat("ERROR: SignatureHash() : nOut={0} out of range\n", nOut);
718 throw new ArgumentOutOfRangeException("nOut", sb.ToString());
720 Array.Resize(ref txTmp.vout, nOut + 1);
722 for (int i = 0; i < nOut; i++)
724 txTmp.vout[i] = new CTxOut();
727 // Let the others update at will
728 for (int i = 0; i < txTmp.vin.Length; i++)
732 txTmp.vin[i].nSequence = 0;
737 // Blank out other inputs completely, not recommended for open transactions
738 if ((nHashType & (int)sigflag.SIGHASH_ANYONECANPAY) != 0)
740 txTmp.vin[0] = txTmp.vin[nIn];
741 Array.Resize(ref txTmp.vin, 1);
744 // Concatenate and hash
745 var txBytes = txTmp.Bytes;
746 var nHashTypeBytes = BitConverter.GetBytes(nHashType);
748 return Hash256.Compute256(ref txBytes, ref nHashTypeBytes);
752 // Script is a stack machine (like Forth) that evaluates a predicate
753 // returning a bool indicating valid or not. There are no loops.
757 /// Script machine exception
759 public class StackMachineException : Exception
761 public StackMachineException()
765 public StackMachineException(string message)
770 public StackMachineException(string message, Exception inner)
771 : base(message, inner)
777 /// Remove last element from stack
779 /// <param name="stack">Stack reference</param>
780 private static void popstack(ref List<byte[]> stack)
782 int nCount = stack.Count;
784 throw new StackMachineException("popstack() : stack empty");
785 stack.RemoveAt(nCount - 1);
789 /// Get element at specified stack depth
791 /// <param name="stack">Stack reference</param>
792 /// <param name="nDepth">Depth</param>
793 /// <returns>Byte sequence</returns>
794 private static byte[] stacktop(ref List<byte[]> stack, int nDepth)
796 int nStackElement = stack.Count + nDepth;
800 StringBuilder sb = new StringBuilder();
801 sb.AppendFormat("stacktop() : positive depth ({0}) has no sense.", nDepth);
803 throw new StackMachineException(sb.ToString());
806 if (nStackElement < 0)
808 StringBuilder sb = new StringBuilder();
809 sb.AppendFormat("stacktop() : nDepth={0} exceeds real stack depth ({1})", nDepth, stack.Count);
811 throw new StackMachineException(sb.ToString());
814 return stack[nStackElement];
818 /// Cast argument to boolean value
820 /// <param name="value">Some byte sequence</param>
821 /// <returns></returns>
822 private static bool CastToBool(byte[] arg)
824 for (var i = 0; i < arg.Length; i++)
828 // Can be negative zero
829 if (i == arg.Length - 1 && arg[i] == 0x80)
842 /// Cast argument to integer value
844 /// <param name="value"></param>
845 /// <returns></returns>
846 private static BigInteger CastToBigInteger(byte[] value)
848 if (value.Length > 4)
850 throw new StackMachineException("CastToBigInteger() : overflow");
853 return new BigInteger(value);
857 /// Execution of script
859 /// <param name="stack"></param>
860 /// <param name="script">Script to execute</param>
861 /// <param name="txTo">Transaction instance</param>
862 /// <param name="nIn">Input number</param>
863 /// <param name="flags">Signature checking flags</param>
864 /// <param name="nHashType">Hash type flag</param>
865 /// <returns></returns>
866 public static bool EvalScript(ref List<byte[]> stack, CScript script, CTransaction txTo, int nIn, int flags, int nHashType)
868 if (script.Bytes.Count() > 10000)
870 return false; // Size limit failed
873 var vfExec = new List<bool>();
876 int nCodeHashBegin = 0;
878 var falseBytes = new byte[0];
879 var trueBytes = new byte[] { 0x01 };
881 var CodeQueue = script.GetByteQUeue();
882 var altStack = new List<byte[]>();
889 while (GetOp(ref CodeQueue, out opcode, out pushArg)) // Read instructions
891 bool fExec = vfExec.IndexOf(false) == -1;
893 if (pushArg.Length > 520)
895 return false; // Script element size limit failed
898 if (opcode > instruction.OP_16 && ++nOpCount > 201)
903 if (fExec && 0 <= opcode && opcode <= instruction.OP_PUSHDATA4)
905 stack.Add(pushArg); // Push argument to stack
907 else if (fExec || (instruction.OP_IF <= opcode && opcode <= instruction.OP_ENDIF))
911 // Disabled instructions
913 case instruction.OP_CAT:
914 case instruction.OP_SUBSTR:
915 case instruction.OP_LEFT:
916 case instruction.OP_RIGHT:
917 case instruction.OP_INVERT:
918 case instruction.OP_AND:
919 case instruction.OP_OR:
920 case instruction.OP_XOR:
921 case instruction.OP_2MUL:
922 case instruction.OP_2DIV:
923 case instruction.OP_MUL:
924 case instruction.OP_DIV:
925 case instruction.OP_MOD:
926 case instruction.OP_LSHIFT:
927 case instruction.OP_RSHIFT:
931 // Push integer instructions
933 case instruction.OP_1NEGATE:
934 case instruction.OP_1:
935 case instruction.OP_2:
936 case instruction.OP_3:
937 case instruction.OP_4:
938 case instruction.OP_5:
939 case instruction.OP_6:
940 case instruction.OP_7:
941 case instruction.OP_8:
942 case instruction.OP_9:
943 case instruction.OP_10:
944 case instruction.OP_11:
945 case instruction.OP_12:
946 case instruction.OP_13:
947 case instruction.OP_14:
948 case instruction.OP_15:
949 case instruction.OP_16:
952 BigInteger bn = DecodeOP_N(opcode, true);
953 stack.Add(bn.ToByteArray());
960 case instruction.OP_NOP:
961 case instruction.OP_NOP1:
962 case instruction.OP_NOP2:
963 case instruction.OP_NOP3:
964 case instruction.OP_NOP4:
965 case instruction.OP_NOP5:
966 case instruction.OP_NOP6:
967 case instruction.OP_NOP7:
968 case instruction.OP_NOP8:
969 case instruction.OP_NOP9:
970 case instruction.OP_NOP10:
979 case instruction.OP_IF:
980 case instruction.OP_NOTIF:
982 // <expression> if [statements] [else [statements]] endif
986 if (stack.Count() < 1)
990 var vch = stacktop(ref stack, -1);
991 fValue = CastToBool(vch);
992 if (opcode == instruction.OP_NOTIF)
1002 case instruction.OP_ELSE:
1004 int nExecCount = vfExec.Count();
1005 if (nExecCount == 0)
1009 vfExec[nExecCount - 1] = !vfExec[nExecCount - 1];
1013 case instruction.OP_ENDIF:
1015 int nExecCount = vfExec.Count();
1016 if (nExecCount == 0)
1020 vfExec.RemoveAt(nExecCount - 1);
1024 case instruction.OP_VERIFY:
1027 // (false -- false) and return
1028 if (stack.Count() < 1)
1033 bool fValue = CastToBool(stacktop(ref stack, -1));
1036 popstack(ref stack);
1045 case instruction.OP_RETURN:
1053 case instruction.OP_TOALTSTACK:
1055 if (stack.Count() < 1)
1059 altStack.Add(stacktop(ref stack, -1));
1060 popstack(ref stack);
1064 case instruction.OP_FROMALTSTACK:
1066 if (altStack.Count() < 1)
1070 stack.Add(stacktop(ref stack, -1));
1071 popstack(ref altStack);
1075 case instruction.OP_2DROP:
1078 if (stack.Count() < 2)
1082 popstack(ref stack);
1083 popstack(ref stack);
1087 case instruction.OP_2DUP:
1089 // (x1 x2 -- x1 x2 x1 x2)
1090 if (stack.Count() < 2)
1094 var vch1 = stacktop(ref stack, -2);
1095 var vch2 = stacktop(ref stack, -1);
1101 case instruction.OP_3DUP:
1103 // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
1104 if (stack.Count() < 3)
1108 var vch1 = stacktop(ref stack, -3);
1109 var vch2 = stacktop(ref stack, -2);
1110 var vch3 = stacktop(ref stack, -1);
1117 case instruction.OP_2OVER:
1119 // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
1120 if (stack.Count() < 4)
1124 var vch1 = stacktop(ref stack, -4);
1125 var vch2 = stacktop(ref stack, -3);
1131 case instruction.OP_2ROT:
1133 int nStackDepth = stack.Count();
1134 // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
1135 if (nStackDepth < 6)
1139 var vch1 = stacktop(ref stack, -6);
1140 var vch2 = stacktop(ref stack, -5);
1141 stack.RemoveRange(nStackDepth - 6, 2);
1147 case instruction.OP_2SWAP:
1149 // (x1 x2 x3 x4 -- x3 x4 x1 x2)
1150 int nStackDepth = stack.Count;
1151 if (nStackDepth < 4)
1155 stack.Swap(nStackDepth - 4, nStackDepth - 2);
1156 stack.Swap(nStackDepth - 3, nStackDepth - 1);
1160 case instruction.OP_IFDUP:
1163 if (stack.Count() < 1)
1168 var vch = stacktop(ref stack, -1);
1170 if (CastToBool(vch))
1177 case instruction.OP_DEPTH:
1180 BigInteger bn = new BigInteger((ushort)stack.Count());
1181 stack.Add(bn.ToByteArray());
1185 case instruction.OP_DROP:
1188 if (stack.Count() < 1)
1193 popstack(ref stack);
1197 case instruction.OP_DUP:
1200 if (stack.Count() < 1)
1205 var vch = stacktop(ref stack, -1);
1210 case instruction.OP_NIP:
1213 int nStackDepth = stack.Count();
1214 if (nStackDepth < 2)
1219 stack.RemoveAt(nStackDepth - 2);
1223 case instruction.OP_OVER:
1225 // (x1 x2 -- x1 x2 x1)
1226 if (stack.Count() < 2)
1231 var vch = stacktop(ref stack, -2);
1236 case instruction.OP_PICK:
1237 case instruction.OP_ROLL:
1239 // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
1240 // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
1242 int nStackDepth = stack.Count();
1243 if (nStackDepth < 2)
1248 int n = (int)CastToBigInteger(stacktop(ref stack, -1));
1249 popstack(ref stack);
1251 if (n < 0 || n >= stack.Count())
1256 var vch = stacktop(ref stack, -n - 1);
1257 if (opcode == instruction.OP_ROLL)
1259 stack.RemoveAt(nStackDepth - n - 1);
1266 case instruction.OP_ROT:
1268 // (x1 x2 x3 -- x2 x3 x1)
1269 // x2 x1 x3 after first swap
1270 // x2 x3 x1 after second swap
1271 int nStackDepth = stack.Count();
1272 if (nStackDepth < 3)
1276 stack.Swap(nStackDepth - 3, nStackDepth - 2);
1277 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1282 case instruction.OP_SWAP:
1285 int nStackDepth = stack.Count();
1286 if (nStackDepth < 2)
1290 stack.Swap(nStackDepth - 2, nStackDepth - 1);
1294 case instruction.OP_TUCK:
1296 // (x1 x2 -- x2 x1 x2)
1297 int nStackDepth = stack.Count();
1298 if (nStackDepth < 2)
1302 var vch = stacktop(ref stack, -1);
1303 stack.Insert(nStackDepth - 2, vch);
1308 case instruction.OP_SIZE:
1311 if (stack.Count() < 1)
1316 var bnSize = new BigInteger((ushort)stacktop(ref stack, -1).Count());
1317 stack.Add(bnSize.ToByteArray());
1325 case instruction.OP_EQUAL:
1326 case instruction.OP_EQUALVERIFY:
1327 //case instruction.OP_NOTEQUAL: // use OP_NUMNOTEQUAL
1330 if (stack.Count() < 2)
1335 var vch1 = stacktop(ref stack, -2);
1336 var vch2 = stacktop(ref stack, -1);
1337 bool fEqual = (vch1.SequenceEqual(vch2));
1338 // OP_NOTEQUAL is disabled because it would be too easy to say
1339 // something like n != 1 and have some wiseguy pass in 1 with extra
1340 // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
1341 //if (opcode == instruction.OP_NOTEQUAL)
1342 // fEqual = !fEqual;
1343 popstack(ref stack);
1344 popstack(ref stack);
1345 stack.Add(fEqual ? trueBytes : falseBytes);
1347 if (opcode == instruction.OP_EQUALVERIFY)
1351 popstack(ref stack);
1365 case instruction.OP_1ADD:
1366 case instruction.OP_1SUB:
1367 case instruction.OP_NEGATE:
1368 case instruction.OP_ABS:
1369 case instruction.OP_NOT:
1370 case instruction.OP_0NOTEQUAL:
1373 if (stack.Count() < 1)
1378 var bn = CastToBigInteger(stacktop(ref stack, -1));
1381 case instruction.OP_1ADD:
1384 case instruction.OP_1SUB:
1387 case instruction.OP_NEGATE:
1390 case instruction.OP_ABS:
1391 bn = BigInteger.Abs(bn);
1393 case instruction.OP_NOT:
1394 bn = bn == 0 ? 1 : 0;
1396 case instruction.OP_0NOTEQUAL:
1397 bn = bn != 0 ? 1 : 0;
1401 popstack(ref stack);
1402 stack.Add(bn.ToByteArray());
1406 case instruction.OP_ADD:
1407 case instruction.OP_SUB:
1408 case instruction.OP_BOOLAND:
1409 case instruction.OP_BOOLOR:
1410 case instruction.OP_NUMEQUAL:
1411 case instruction.OP_NUMEQUALVERIFY:
1412 case instruction.OP_NUMNOTEQUAL:
1413 case instruction.OP_LESSTHAN:
1414 case instruction.OP_GREATERTHAN:
1415 case instruction.OP_LESSTHANOREQUAL:
1416 case instruction.OP_GREATERTHANOREQUAL:
1417 case instruction.OP_MIN:
1418 case instruction.OP_MAX:
1421 if (stack.Count() < 2)
1426 var bn1 = CastToBigInteger(stacktop(ref stack, -2));
1427 var bn2 = CastToBigInteger(stacktop(ref stack, -1));
1432 case instruction.OP_ADD:
1435 case instruction.OP_SUB:
1438 case instruction.OP_BOOLAND:
1439 bn = (bn1 != 0 && bn2 != 0) ? 1 : 0;
1441 case instruction.OP_BOOLOR:
1442 bn = (bn1 != 0 || bn2 != 0) ? 1 : 0;
1444 case instruction.OP_NUMEQUAL:
1445 bn = (bn1 == bn2) ? 1 : 0;
1447 case instruction.OP_NUMEQUALVERIFY:
1448 bn = (bn1 == bn2) ? 1 : 0;
1450 case instruction.OP_NUMNOTEQUAL:
1451 bn = (bn1 != bn2) ? 1 : 0;
1453 case instruction.OP_LESSTHAN:
1454 bn = (bn1 < bn2) ? 1 : 0;
1456 case instruction.OP_GREATERTHAN:
1457 bn = (bn1 > bn2) ? 1 : 0;
1459 case instruction.OP_LESSTHANOREQUAL:
1460 bn = (bn1 <= bn2) ? 1 : 0;
1462 case instruction.OP_GREATERTHANOREQUAL:
1463 bn = (bn1 >= bn2) ? 1 : 0;
1465 case instruction.OP_MIN:
1466 bn = (bn1 < bn2 ? bn1 : bn2);
1468 case instruction.OP_MAX:
1469 bn = (bn1 > bn2 ? bn1 : bn2);
1473 popstack(ref stack);
1474 popstack(ref stack);
1475 stack.Add(bn.ToByteArray());
1477 if (opcode == instruction.OP_NUMEQUALVERIFY)
1479 if (CastToBool(stacktop(ref stack, -1)))
1481 popstack(ref stack);
1491 case instruction.OP_WITHIN:
1493 // (x min max -- out)
1494 if (stack.Count() < 3)
1499 var bn1 = CastToBigInteger(stacktop(ref stack, -3));
1500 var bn2 = CastToBigInteger(stacktop(ref stack, -2));
1501 var bn3 = CastToBigInteger(stacktop(ref stack, -1));
1503 bool fValue = (bn2 <= bn1 && bn1 < bn3);
1505 popstack(ref stack);
1506 popstack(ref stack);
1507 popstack(ref stack);
1509 stack.Add(fValue ? trueBytes : falseBytes);
1516 case instruction.OP_RIPEMD160:
1517 case instruction.OP_SHA1:
1518 case instruction.OP_SHA256:
1519 case instruction.OP_HASH160:
1520 case instruction.OP_HASH256:
1523 if (stack.Count() < 1)
1528 var data = stacktop(ref stack, -1);
1532 case instruction.OP_HASH160:
1533 hash = Hash160.Compute160(data);
1535 case instruction.OP_HASH256:
1536 hash = Hash256.Compute256(data);
1538 case instruction.OP_SHA1:
1539 hash = SHA1.Compute1(data);
1541 case instruction.OP_SHA256:
1542 hash = SHA256.Compute256(data);
1544 case instruction.OP_RIPEMD160:
1545 hash = RIPEMD160.Compute160(data);
1548 popstack(ref stack);
1549 stack.Add(hash.hashBytes);
1553 case instruction.OP_CODESEPARATOR:
1555 // Hash starts after the code separator
1556 nCodeHashBegin = CodeQueue.CurrentIndex;
1560 case instruction.OP_CHECKSIG:
1561 case instruction.OP_CHECKSIGVERIFY:
1563 // (sig pubkey -- bool)
1564 if (stack.Count() < 2)
1569 byte[] sigBytes = stacktop(ref stack, -2);
1570 byte[] pubkeyBytes = stacktop(ref stack, -1);
1572 // Subset of script starting at the most recent codeseparator
1573 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1575 // There's no way for a signature to sign itself
1576 scriptCode.RemovePattern(sigBytes);
1578 bool fSuccess = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubkeyBytes, flags) && CheckSig(sigBytes, pubkeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1580 popstack(ref stack);
1581 popstack(ref stack);
1583 stack.Add(fSuccess ? trueBytes : falseBytes);
1585 if (opcode == instruction.OP_CHECKSIGVERIFY)
1589 popstack(ref stack);
1599 case instruction.OP_CHECKMULTISIG:
1600 case instruction.OP_CHECKMULTISIGVERIFY:
1602 // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
1605 if (stack.Count() < i)
1610 int nKeysCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1611 if (nKeysCount < 0 || nKeysCount > 20)
1615 nOpCount += nKeysCount;
1622 if (stack.Count() < i)
1627 int nSigsCount = (int)CastToBigInteger(stacktop(ref stack, -i));
1628 if (nSigsCount < 0 || nSigsCount > nKeysCount)
1634 if (stack.Count() < i)
1639 // Subset of script starting at the most recent codeseparator
1640 CScript scriptCode = new CScript(script.Bytes.Skip(nCodeHashBegin));
1642 // There is no way for a signature to sign itself, so we need to drop the signatures
1643 for (int k = 0; k < nSigsCount; k++)
1645 var vchSig = stacktop(ref stack, -isig - k);
1646 scriptCode.RemovePattern(vchSig);
1649 bool fSuccess = true;
1650 while (fSuccess && nSigsCount > 0)
1652 var sigBytes = stacktop(ref stack, -isig);
1653 var pubKeyBytes = stacktop(ref stack, -ikey);
1656 bool fOk = IsCanonicalSignature(sigBytes, flags) && IsCanonicalPubKey(pubKeyBytes, flags) && CheckSig(sigBytes, pubKeyBytes, scriptCode, txTo, nIn, nHashType, flags);
1666 // If there are more signatures left than keys left,
1667 // then too many signatures have failed
1668 if (nSigsCount > nKeysCount)
1676 popstack(ref stack);
1679 // A bug causes CHECKMULTISIG to consume one extra argument
1680 // whose contents were not checked in any way.
1682 // Unfortunately this is a potential source of mutability,
1683 // so optionally verify it is exactly equal to zero prior
1684 // to removing it from the stack.
1685 if (stack.Count() < 1)
1689 if ((flags & (int)scriptflag.SCRIPT_VERIFY_NULLDUMMY) != 0 && stacktop(ref stack, -1).Count() != 0)
1691 return false; // CHECKMULTISIG dummy argument not null
1693 popstack(ref stack);
1695 stack.Add(fSuccess ? trueBytes : falseBytes);
1697 if (opcode == instruction.OP_CHECKMULTISIGVERIFY)
1701 popstack(ref stack);
1716 if (stack.Count() + altStack.Count() > 1000)
1724 // If there are any exceptions then just return false.
1728 if (vfExec.Count() != 0)
1730 // Something went wrong with conditional instructions.
1738 public static bool IsCanonicalPubKey(byte[] pubKeyBytes, int flags)
1740 if ((flags & (int)scriptflag.SCRIPT_VERIFY_STRICTENC) == 0)
1743 if (pubKeyBytes.Length < 33)
1744 return false; // Non-canonical public key: too short
1745 if (pubKeyBytes[0] == 0x04)
1747 if (pubKeyBytes.Length != 65)
1748 return false; // Non-canonical public key: invalid length for uncompressed key
1750 else if (pubKeyBytes[0] == 0x02 || pubKeyBytes[0] == 0x03)
1752 if (pubKeyBytes.Length != 33)
1753 return false; // Non-canonical public key: invalid length for compressed key
1757 return false; // Non-canonical public key: compressed nor uncompressed
1762 public static bool IsCanonicalSignature(byte[] sigBytes, int flags)
1770 /// Check signature.
1772 /// <param name="sigBytes">Signature</param>
1773 /// <param name="pubkeyBytes">Public key</param>
1774 /// <param name="script">Spending script</param>
1775 /// <param name="txTo">CTransaction instance</param>
1776 /// <param name="nIn">Input number</param>
1777 /// <param name="nHashType">Hashing type flag</param>
1778 /// <param name="flags">Signature checking flags</param>
1779 /// <returns>Checking result</returns>
1780 public static bool CheckSig(byte[] sigBytes, byte[] pubkeyBytes, CScript script, CTransaction txTo, int nIn, int nHashType, int flags)
1786 // Trying to initialize the public key instance
1788 pubkey = new CPubKey(pubkeyBytes);
1792 // Exception occurred while initializing the public key
1797 if (!pubkey.IsValid)
1802 if (sigBytes.Length == 0)
1807 // Hash type is one byte tacked on to the end of the signature
1810 nHashType = sigBytes.Last();
1812 else if (nHashType != sigBytes.Last())
1818 Array.Resize(ref sigBytes, sigBytes.Length - 1);
1820 var sighash = SignatureHash(script, txTo, nIn, nHashType);
1822 if (!pubkey.VerifySignature(sighash, sigBytes))
1831 /// Evaluates the both scriptSig and scriptPubKey.
1833 /// <param name="scriptSig"></param>
1834 /// <param name="scriptPubKey"></param>
1835 /// <param name="txTo">Transaction</param>
1836 /// <param name="nIn">Input number</param>
1837 /// <param name="flags">Script validation flags</param>
1838 /// <param name="nHashType">Hash type flag</param>
1839 /// <returns></returns>
1840 public static bool VerifyScript(CScript scriptSig, CScript scriptPubKey, CTransaction txTo, int nIn, int flags, int nHashType)
1842 var stack = new List<byte[]>();
1843 List<byte[]> stackCopy = null;
1845 if (!EvalScript(ref stack, scriptSig, txTo, nIn, flags, nHashType))
1850 if ((flags & (int)scriptflag.SCRIPT_VERIFY_P2SH) != 0)
1852 stackCopy = new List<byte[]>(stack);
1855 if (!EvalScript(ref stack, scriptPubKey, txTo, nIn, flags, nHashType))
1860 if (stack.Count == 0 || CastToBool(stack.Last()) == false)
1865 // Additional validation for spend-to-script-hash transactions:
1866 if ((flags & (int)scriptflag.SCRIPT_VERIFY_P2SH) != 0 && scriptPubKey.IsPayToScriptHash)
1868 if (!scriptSig.IsPushOnly) // scriptSig must be literals-only
1873 // stackCopy cannot be empty here, because if it was the
1874 // P2SH HASH <> EQUAL scriptPubKey would be evaluated with
1875 // an empty stack and the EvalScript above would return false.
1877 if (stackCopy.Count == 0)
1879 throw new StackMachineException("Fatal script validation error.");
1882 var pubKey2 = new CScript(stackCopy.Last());
1883 popstack(ref stackCopy);
1885 if (!EvalScript(ref stackCopy, pubKey2, txTo, nIn, flags, nHashType))
1887 if (stackCopy.Count == 0)
1890 return CastToBool(stackCopy.Last());