bool CheckSig(ScriptStack stack, byte[] sigHash)
{
var publicKey = stack.PopPublicKey();
var signature = stack.PopSignature();
var result = publicKey.Verify(sigHash, signature);
return(result);
}
IList <Signature> PopSignatures(ScriptStack stack, BigInteger count)
{
var signatures = new List <Signature>();
while (count-- > 0)
{
signatures.Add(stack.PopSignature());
}
return(signatures);
}
IList <PublicKey> PopKeys(ScriptStack stack, BigInteger count)
{
var publicKeys = new List <PublicKey>();
while (count-- > 0)
{
publicKeys.Add(stack.PopPublicKey());
}
return(publicKeys);
}
bool Evaluate(OpCode opCode, ScriptStack stack, byte[] sigHash)
{
switch (opCode)
{
case OpCode.OP_CHECKSIG:
return(stack.Push(CheckSig(stack, sigHash)));
case OpCode.OP_CHECKMULTISIG:
return(stack.Push(CheckMultiSig(stack, sigHash)));
default:
throw new NotImplementedException();
}
}
bool CheckMultiSig(ScriptStack stack, byte[] sigHash)
{
var publicKeys = PopKeys(stack, stack.PopInt());
var signatures = PopSignatures(stack, stack.PopInt());
stack.PopInt(); // Satoshi off-by-one
var keyIndex = 0;
foreach (var signature in signatures)
{
while (!publicKeys[keyIndex++].Verify(sigHash, signature))
{
if (keyIndex >= publicKeys.Count)
{
return(false);
}
}
}
return(true);
}
bool Evaluate(OpCode opCode, ScriptStack stack, ScriptStack altStack)
{
throw new NotImplementedException();
}
bool Evaluate(OpCode opCode, ScriptStack stack, IEnumerable <object> commands)
{
throw new NotImplementedException();
}
public bool Evaluate(IEnumerable <object> scriptCommands, byte[]?sigHash = null)
{
var commands = new Queue <object>(scriptCommands ?? throw new ArgumentNullException(nameof(scriptCommands)));
var stack = new ScriptStack();
var altStack = new ScriptStack();
while (commands.Count > 0)
{
if (IsPayToScriptHash(commands))
{
var redeemScript = DecodeRedeemScript((byte[])commands.Dequeue());
commands = new Queue <object>(redeemScript.Commands);
}
var command = commands.Dequeue();
if (command is byte[] bytes)
{
stack.Push(bytes);
}
else if (command is OpCode opCode)
{
var result = false;
try
{
switch (GetOpertationType(opCode))
{
case OpertationType.Stack:
result = Evaluate(opCode, stack);
break;
case OpertationType.SigHash:
result = Evaluate(opCode, stack, sigHash ?? throw new ArgumentNullException(nameof(sigHash)));
break;
case OpertationType.Commands:
result = Evaluate(opCode, stack, commands);
break;
case OpertationType.AltStack:
result = Evaluate(opCode, stack, altStack);
break;
}
}
catch (FormatException ex)
{
if (throwOnFailure)
{
throw new VerificationException("Bad format", ex);
}
}
catch (InvalidOperationException ex)
{
if (throwOnFailure)
{
throw new VerificationException("Bad operation", ex);
}
}
if (!result)
{
if (throwOnFailure)
{
throw new VerificationException("Script evaluation false");
}
return(false);
}
}
else
{
throw new InvalidOperationException("Invalid command type");
}
}
return(stack.Count > 0 && stack.Pop().Length > 0);
}
bool Evaluate(OpCode opCode, ScriptStack stack)
{
switch (opCode)
{
case OpCode.OP_0:
return(stack.Push(0));
case OpCode.OP_1NEGATE:
return(stack.Push(-1));
case OpCode.OP_1:
case OpCode.OP_2:
case OpCode.OP_3:
case OpCode.OP_4:
case OpCode.OP_5:
case OpCode.OP_6:
case OpCode.OP_7:
case OpCode.OP_8:
case OpCode.OP_9:
case OpCode.OP_10:
case OpCode.OP_11:
case OpCode.OP_12:
case OpCode.OP_13:
case OpCode.OP_14:
case OpCode.OP_15:
case OpCode.OP_16:
return(stack.Push((int)opCode - (int)OpCode.OP_1 + 1));
case OpCode.OP_NOP:
case OpCode.OP_NOP1:
case OpCode.OP_NOP4:
case OpCode.OP_NOP5:
case OpCode.OP_NOP6:
case OpCode.OP_NOP7:
case OpCode.OP_NOP8:
case OpCode.OP_NOP9:
case OpCode.OP_NOP10:
return(true);
case OpCode.OP_DUP:
return(stack.Push(stack.Peek()));
case OpCode.OP_2DUP:
var d1 = stack.Pop();
var d2 = stack.Peek();
stack.Push(d1);
stack.Push(d2);
return(stack.Push(d1));
case OpCode.OP_SWAP:
var s1 = stack.Pop();
var s2 = stack.Pop();
stack.Push(s1);
return(stack.Push(s2));
case OpCode.OP_VERIFY:
return(stack.Pop().Length > 0);
case OpCode.OP_EQUALVERIFY:
return(stack.Pop().SequenceEqual(stack.Pop()));
case OpCode.OP_HASH160:
return(stack.Push(Cipher.Hash160(stack.Pop())));
case OpCode.OP_SHA1:
return(stack.Push(Cipher.Sha1(stack.Pop())));
case OpCode.OP_ADD:
return(stack.Push(stack.PopInt() + stack.PopInt()));
case OpCode.OP_MUL:
return(stack.Push(stack.PopInt() * stack.PopInt()));
case OpCode.OP_EQUAL:
return(stack.Push(stack.Pop().SequenceEqual(stack.Pop()) ? 1 : 0));
case OpCode.OP_NOT:
return(stack.Push(stack.Pop().Length == 0 ? 1 : 0));
default:
throw new InvalidOperationException("Unknown operation: " + opCode);
}
}