Example #1
0
func main() {
	key, _ := hex.DecodeString("040eaebcd1df2df853d66ce0e1b0fda07f67d1cabefde98514aad795b86a6ea66dbeb26b67d7a00e2447baeccc8a4cef7cd3cad67376ac1c5785aeebb4f6441c16")
	sig, _ := hex.DecodeString("3045022100fe00e013c244062847045ae7eb73b03fca583e9aa5dbd030a8fd1c6dfcf11b1002207d0d04fed8fa1e93007468d5a9e134b0a7023b6d31db4e50942d43a250f4d07c01")
	msg, _ := hex.DecodeString("3382219555ddbb5b00e0090f469e590ba1eae03c7f28ab937de330aa60294ed6")
	sta := time.Now()
	for i := 0; i < CNT; i++ {
		if !btc.EcdsaVerify(key, sig, msg) {
			println("Verify error")
			return
		}
	}
	sto := time.Now()
	println((sto.UnixNano()-sta.UnixNano())/int64(CNT*1000), "us per ECDSA_Verify")
}
Example #2
0
// reorder signatures to meet order of the keys
// remove signatuers made by the same keys
// remove exessive signatures (keeps transaction size down)
func multisig_reorder(tx *btc.Tx) (all_signed bool) {
	all_signed = true
	for i := range tx.TxIn {
		ms, _ := btc.NewMultiSigFromScript(tx.TxIn[i].ScriptSig)
		if ms == nil {
			continue
		}
		hash := tx.SignatureHash(ms.P2SH(), i, btc.SIGHASH_ALL)

		var sigs []*btc.Signature
		for ki := range ms.PublicKeys {
			var sig *btc.Signature
			for si := range ms.Signatures {
				if btc.EcdsaVerify(ms.PublicKeys[ki], ms.Signatures[si].Bytes(), hash) {
					//fmt.Println("Key number", ki, "has signature number", si)
					sig = ms.Signatures[si]
					break
				}
			}
			if sig != nil {
				sigs = append(sigs, sig)
			} else if *verbose {
				fmt.Println("WARNING: Key number", ki, "has no matching signature")
			}

			if !*allowextramsigns && uint(len(sigs)) >= ms.SigsNeeded {
				break
			}
		}

		if *verbose {
			if len(ms.Signatures) > len(sigs) {
				fmt.Println("WARNING: Some signatures are obsolete and will be removed", len(ms.Signatures), "=>", len(sigs))
			} else if len(ms.Signatures) < len(sigs) {
				fmt.Println("It appears that same key is re-used.", len(sigs)-len(ms.Signatures), "more signatures were added")
			}
		}

		ms.Signatures = sigs
		tx.TxIn[i].ScriptSig = ms.Bytes()

		if len(sigs) < int(ms.SigsNeeded) {
			all_signed = false
		}
	}
	return
}
Example #3
0
func main() {
	var msg []byte

	flag.Parse()

	if *help || *addr == "" || *sign == "" {
		flag.PrintDefaults()
		return
	}

	ad, er := btc.NewAddrFromString(*addr)
	if !*litecoin && ad != nil && ad.Version == ltc.AddrVerPubkey(false) {
		*litecoin = true
	}
	if er != nil {
		println("Address:", er.Error())
		flag.PrintDefaults()
		return
	}

	nv, btcsig, er := btc.ParseMessageSignature(*sign)
	if er != nil {
		println("ParseMessageSignature:", er.Error())
		return
	}

	if *mess != "" {
		msg = []byte(*mess)
	} else if *mfil != "" {
		msg, er = ioutil.ReadFile(*mfil)
		if er != nil {
			println(er.Error())
			return
		}
	} else {
		if *verb {
			fmt.Println("Enter the message:")
		}
		msg, _ = ioutil.ReadAll(os.Stdin)
	}

	if *unix {
		if *verb {
			fmt.Println("Enforcing Unix text format")
		}
		msg = bytes.Replace(msg, []byte{'\r'}, nil, -1)
	}

	hash := make([]byte, 32)
	if *litecoin {
		ltc.HashFromMessage(msg, hash)
	} else {
		btc.HashFromMessage(msg, hash)
	}

	compressed := false
	if nv >= 31 {
		if *verb {
			fmt.Println("compressed key")
		}
		nv -= 4
		compressed = true
	}

	pub := btcsig.RecoverPublicKey(hash[:], int(nv-27))
	if pub != nil {
		pk := pub.Bytes(compressed)
		ok := btc.EcdsaVerify(pk, btcsig.Bytes(), hash)
		if ok {
			sa := btc.NewAddrFromPubkey(pk, ad.Version)
			if ad.Hash160 != sa.Hash160 {
				fmt.Println("BAD signature for", ad.String())
				if bytes.IndexByte(msg, '\r') != -1 {
					fmt.Println("You have CR chars in the message. Try to verify with -u switch.")
				}
				os.Exit(1)
			} else {
				fmt.Println("Signature OK")
			}
		} else {
			println("BAD signature")
			os.Exit(1)
		}
	} else {
		println("BAD, BAD, BAD signature")
		os.Exit(1)
	}
}
Example #4
0
func evalScript(p []byte, stack *scrStack, tx *btc.Tx, inp int) bool {
	if DBG_SCR {
		println("script len", len(p))
	}

	if len(p) > 10000 {
		if DBG_ERR {
			println("script too long", len(p))
		}
		return false
	}

	defer func() {
		if r := recover(); r != nil {
			if DBG_ERR {
				err, ok := r.(error)
				if !ok {
					err = fmt.Errorf("pkg: %v", r)
				}
				println("evalScript panic:", err.Error())
			}
		}
	}()

	var exestack scrStack
	var altstack scrStack
	sta, idx, opcnt := 0, 0, 0
	for idx < len(p) {
		inexec := exestack.nofalse()

		// Read instruction
		opcode, pushval, n, e := btc.GetOpcode(p[idx:])
		if e != nil {
			//println(e.Error())
			//println("A", idx, hex.EncodeToString(p))
			return false
		}
		idx += n

		if DBG_SCR {
			fmt.Printf("\nExecuting opcode 0x%02x  n=%d  inexec:%t  push:%s..\n",
				opcode, n, inexec, hex.EncodeToString(pushval))
			stack.print()
		}

		if pushval != nil && len(pushval) > btc.MAX_SCRIPT_ELEMENT_SIZE {
			if DBG_ERR {
				println("pushval too long", len(pushval))
			}
			return false
		}

		if opcode > 0x60 {
			opcnt++
			if opcnt > 201 {
				if DBG_ERR {
					println("evalScript: too many opcodes A")
				}
				return false
			}
		}

		if opcode == 0x7e /*OP_CAT*/ ||
			opcode == 0x7f /*OP_SUBSTR*/ ||
			opcode == 0x80 /*OP_LEFT*/ ||
			opcode == 0x81 /*OP_RIGHT*/ ||
			opcode == 0x83 /*OP_INVERT*/ ||
			opcode == 0x84 /*OP_AND*/ ||
			opcode == 0x85 /*OP_OR*/ ||
			opcode == 0x86 /*OP_XOR*/ ||
			opcode == 0x8d /*OP_2MUL*/ ||
			opcode == 0x8e /*OP_2DIV*/ ||
			opcode == 0x95 /*OP_MUL*/ ||
			opcode == 0x96 /*OP_DIV*/ ||
			opcode == 0x97 /*OP_MOD*/ ||
			opcode == 0x98 /*OP_LSHIFT*/ ||
			opcode == 0x99 /*OP_RSHIFT*/ {
			if DBG_ERR {
				println("Unsupported opcode", opcode)
			}
			return false
		}

		if inexec && 0 <= opcode && opcode <= btc.OP_PUSHDATA4 {
			stack.push(pushval)
			if DBG_SCR {
				fmt.Println("pushed", len(pushval), "bytes")
			}
		} else if inexec || (0x63 /*OP_IF*/ <= opcode && opcode <= 0x68 /*OP_ENDIF*/) {
			switch {
			case opcode == 0x4f: // OP_1NEGATE
				stack.pushInt(-1)

			case opcode >= 0x51 && opcode <= 0x60: // OP_1-OP_16
				stack.pushInt(int64(opcode - 0x50))

			case opcode == 0x61: // OP_NOP
				// Do nothing

			/* - not handled
			OP_VER = 0x62
			*/

			case opcode == 0x63 || opcode == 0x64: //OP_IF || OP_NOTIF
				// <expression> if [statements] [else [statements]] endif
				val := false
				if inexec {
					if stack.size() < 1 {
						if DBG_ERR {
							println("Stack too short for", opcode)
						}
						return false
					}
					if opcode == 0x63 /*OP_IF*/ {
						val = stack.popBool()
					} else {
						val = !stack.popBool()
					}
				}
				if DBG_SCR {
					println(inexec, "if pushing", val, "...")
				}
				exestack.pushBool(val)

			/* - not handled
			   OP_VERIF = 0x65,
			   OP_VERNOTIF = 0x66,
			*/
			case opcode == 0x67: //OP_ELSE
				if exestack.size() == 0 {
					if DBG_ERR {
						println("exestack empty in OP_ELSE")
					}
				}
				exestack.pushBool(!exestack.popBool())

			case opcode == 0x68: //OP_ENDIF
				if exestack.size() == 0 {
					if DBG_ERR {
						println("exestack empty in OP_ENDIF")
					}
				}
				exestack.pop()

			case opcode == 0x69: //OP_VERIFY
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				if !stack.topBool(-1) {
					return false
				}
				stack.pop()

			case opcode == 0x6b: //OP_TOALTSTACK
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				altstack.push(stack.pop())

			case opcode == 0x6c: //OP_FROMALTSTACK
				if altstack.size() < 1 {
					if DBG_ERR {
						println("AltStack too short for opcode", opcode)
					}
					return false
				}
				stack.push(altstack.pop())

			case opcode == 0x6d: //OP_2DROP
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pop()
				stack.pop()

			case opcode == 0x6e: //OP_2DUP
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x1 := stack.top(-1)
				x2 := stack.top(-2)
				stack.push(x2)
				stack.push(x1)

			case opcode == 0x6f: //OP_3DUP
				if stack.size() < 3 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x1 := stack.top(-3)
				x2 := stack.top(-2)
				x3 := stack.top(-1)
				stack.push(x1)
				stack.push(x2)
				stack.push(x3)

			case opcode == 0x70: //OP_2OVER
				if stack.size() < 4 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x1 := stack.top(-4)
				x2 := stack.top(-3)
				stack.push(x1)
				stack.push(x2)

			case opcode == 0x71: //OP_2ROT
				// (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
				if stack.size() < 6 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x6 := stack.pop()
				x5 := stack.pop()
				x4 := stack.pop()
				x3 := stack.pop()
				x2 := stack.pop()
				x1 := stack.pop()
				stack.push(x3)
				stack.push(x4)
				stack.push(x5)
				stack.push(x6)
				stack.push(x1)
				stack.push(x2)

			case opcode == 0x72: //OP_2SWAP
				// (x1 x2 x3 x4 -- x3 x4 x1 x2)
				if stack.size() < 4 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x4 := stack.pop()
				x3 := stack.pop()
				x2 := stack.pop()
				x1 := stack.pop()
				stack.push(x3)
				stack.push(x4)
				stack.push(x1)
				stack.push(x2)

			case opcode == 0x73: //OP_IFDUP
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				if stack.topBool(-1) {
					stack.push(stack.top(-1))
				}

			case opcode == 0x74: //OP_DEPTH
				stack.pushInt(int64(stack.size()))

			case opcode == 0x75: //OP_DROP
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pop()

			case opcode == 0x76: //OP_DUP
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				el := stack.pop()
				stack.push(el)
				stack.push(el)

			case opcode == 0x77: //OP_NIP
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x := stack.pop()
				stack.pop()
				stack.push(x)

			case opcode == 0x78: //OP_OVER
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.push(stack.top(-2))

			case opcode == 0x79 || opcode == 0x7a: //OP_PICK || OP_ROLL
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				n := stack.popInt()
				if n < 0 || n >= int64(stack.size()) {
					if DBG_ERR {
						println("Wrong n for opcode", opcode)
					}
					return false
				}
				if opcode == 0x79 /*OP_PICK*/ {
					stack.push(stack.top(int(-1 - n)))
				} else if n > 0 {
					tmp := make([][]byte, n)
					for i := range tmp {
						tmp[i] = stack.pop()
					}
					xn := stack.pop()
					for i := len(tmp) - 1; i >= 0; i-- {
						stack.push(tmp[i])
					}
					stack.push(xn)
				}

			case opcode == 0x7b: //OP_ROT
				if stack.size() < 3 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x3 := stack.pop()
				x2 := stack.pop()
				x1 := stack.pop()
				stack.push(x2)
				stack.push(x3)
				stack.push(x1)

			case opcode == 0x7c: //OP_SWAP
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x1 := stack.pop()
				x2 := stack.pop()
				stack.push(x1)
				stack.push(x2)

			case opcode == 0x7d: //OP_TUCK
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				x1 := stack.pop()
				x2 := stack.pop()
				stack.push(x1)
				stack.push(x2)
				stack.push(x1)

			case opcode == 0x82: //OP_SIZE
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushInt(int64(len(stack.top(-1))))

			case opcode == 0x87 || opcode == 0x88: //OP_EQUAL || OP_EQUALVERIFY
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				a := stack.pop()
				b := stack.pop()
				if opcode == 0x88 { //OP_EQUALVERIFY
					if !bytes.Equal(a, b) {
						return false
					}
				} else {
					stack.pushBool(bytes.Equal(a, b))
				}

			/* - not handled
			OP_RESERVED1 = 0x89,
			OP_RESERVED2 = 0x8a,
			*/

			case opcode == 0x8b: //OP_1ADD
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushInt(stack.popInt() + 1)

			case opcode == 0x8c: //OP_1SUB
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushInt(stack.popInt() - 1)

			case opcode == 0x8f: //OP_NEGATE
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushInt(-stack.popInt())

			case opcode == 0x90: //OP_ABS
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				a := stack.popInt()
				if a < 0 {
					stack.pushInt(-a)
				} else {
					stack.pushInt(a)
				}

			case opcode == 0x91: //OP_NOT
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushBool(stack.popInt() == 0)

			case opcode == 0x92: //OP_0NOTEQUAL
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				stack.pushBool(stack.popBool())

			case opcode == 0x93 || //OP_ADD
				opcode == 0x94 || //OP_SUB
				opcode == 0x9a || //OP_BOOLAND
				opcode == 0x9b || //OP_BOOLOR
				opcode == 0x9c || opcode == 0x9d || //OP_NUMEQUAL || OP_NUMEQUALVERIFY
				opcode == 0x9e || //OP_NUMNOTEQUAL
				opcode == 0x9f || //OP_LESSTHAN
				opcode == 0xa0 || //OP_GREATERTHAN
				opcode == 0xa1 || //OP_LESSTHANOREQUAL
				opcode == 0xa2 || //OP_GREATERTHANOREQUAL
				opcode == 0xa3 || //OP_MIN
				opcode == 0xa4: //OP_MAX
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				bn2 := stack.popInt()
				bn1 := stack.popInt()
				var bn int64
				switch opcode {
				case 0x93:
					bn = bn1 + bn2 // OP_ADD
				case 0x94:
					bn = bn1 - bn2 // OP_SUB
				case 0x9a:
					bn = b2i(bn1 != 0 && bn2 != 0) // OP_BOOLAND
				case 0x9b:
					bn = b2i(bn1 != 0 || bn2 != 0) // OP_BOOLOR
				case 0x9c:
					bn = b2i(bn1 == bn2) // OP_NUMEQUAL
				case 0x9d:
					bn = b2i(bn1 == bn2) // OP_NUMEQUALVERIFY
				case 0x9e:
					bn = b2i(bn1 != bn2) // OP_NUMNOTEQUAL
				case 0x9f:
					bn = b2i(bn1 < bn2) // OP_LESSTHAN
				case 0xa0:
					bn = b2i(bn1 > bn2) // OP_GREATERTHAN
				case 0xa1:
					bn = b2i(bn1 <= bn2) // OP_LESSTHANOREQUAL
				case 0xa2:
					bn = b2i(bn1 >= bn2) // OP_GREATERTHANOREQUAL
				case 0xa3: // OP_MIN
					if bn1 < bn2 {
						bn = bn1
					} else {
						bn = bn2
					}
				case 0xa4: // OP_MAX
					if bn1 > bn2 {
						bn = bn1
					} else {
						bn = bn2
					}
				default:
					panic("invalid opcode")
				}
				if opcode == 0x9d { //OP_NUMEQUALVERIFY
					if bn == 0 {
						return false
					}
				} else {
					stack.pushInt(bn)
				}

			case opcode == 0xa5: //OP_WITHIN
				if stack.size() < 3 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				bn3 := stack.popInt()
				bn2 := stack.popInt()
				bn1 := stack.popInt()
				stack.pushBool(bn2 <= bn1 && bn1 < bn3)

			case opcode == 0xa6: //OP_RIPEMD160
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				rim := ripemd160.New()
				rim.Write(stack.pop()[:])
				stack.push(rim.Sum(nil)[:])

			case opcode == 0xa7: //OP_SHA1
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				sha := sha1.New()
				sha.Write(stack.pop()[:])
				stack.push(sha.Sum(nil)[:])

			case opcode == 0xa8: //OP_SHA256
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				sha := sha256.New()
				sha.Write(stack.pop()[:])
				stack.push(sha.Sum(nil)[:])

			case opcode == 0xa9: //OP_HASH160
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				rim160 := btc.Rimp160AfterSha256(stack.pop())
				stack.push(rim160[:])

			case opcode == 0xaa: //OP_HASH256
				if stack.size() < 1 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				h := btc.Sha2Sum(stack.pop())
				stack.push(h[:])

			case opcode == 0xab: // OP_CODESEPARATOR
				sta = idx

			case opcode == 0xac || opcode == 0xad: // OP_CHECKSIG || OP_CHECKSIGVERIFY
				if stack.size() < 2 {
					if DBG_ERR {
						println("Stack too short for opcode", opcode)
					}
					return false
				}
				var ok bool
				pk := stack.pop()
				si := stack.pop()
				if len(si) > 9 {
					sh := tx.SignatureHash(delSig(p[sta:], si), inp, int32(si[len(si)-1]))
					ok = btc.EcdsaVerify(pk, si, sh)
					if !ok && DBG_ERR {
						println("EcdsaVerify fail 1")
					}
				}
				if DBG_SCR {
					println("ver:", ok)
				}
				if opcode == 0xad {
					if !ok { // OP_CHECKSIGVERIFY
						return false
					}
				} else { // OP_CHECKSIG
					stack.pushBool(ok)
				}

			case opcode == 0xae || opcode == 0xaf: //OP_CHECKMULTISIG || OP_CHECKMULTISIGVERIFY
				//println("OP_CHECKMULTISIG ...")
				//stack.print()
				if stack.size() < 1 {
					if DBG_ERR {
						println("OP_CHECKMULTISIG: Stack too short A")
					}
					return false
				}
				i := 1
				keyscnt := stack.topInt(-i)
				if keyscnt < 0 || keyscnt > 20 {
					println("OP_CHECKMULTISIG: Wrong number of keys")
					return false
				}
				opcnt += int(keyscnt)
				if opcnt > 201 {
					if DBG_ERR {
						println("evalScript: too many opcodes B")
					}
					return false
				}
				i++
				ikey := i
				i += int(keyscnt)
				if stack.size() < i {
					if DBG_ERR {
						println("OP_CHECKMULTISIG: Stack too short B")
					}
					return false
				}
				sigscnt := stack.topInt(-i)
				if sigscnt < 0 || sigscnt > keyscnt {
					println("OP_CHECKMULTISIG: sigscnt error")
					return false
				}
				i++
				isig := i
				i += int(sigscnt)
				if stack.size() < i {
					if DBG_ERR {
						println("OP_CHECKMULTISIG: Stack too short C")
					}
					return false
				}

				xxx := p[sta:]
				for k := 0; k < int(sigscnt); k++ {
					xxx = delSig(xxx, stack.top(-isig-k))
				}

				success := true
				for sigscnt > 0 {
					pk := stack.top(-ikey)
					si := stack.top(-isig)
					if len(si) > 9 && ((len(pk) == 65 && pk[0] == 4) || (len(pk) == 33 && (pk[0]|1) == 3)) {
						sh := tx.SignatureHash(xxx, inp, int32(si[len(si)-1]))
						if btc.EcdsaVerify(pk, si, sh) {
							isig++
							sigscnt--
						}
					}

					ikey++
					keyscnt--

					// If there are more signatures left than keys left,
					// then too many signatures have failed
					if sigscnt > keyscnt {
						success = false
						break
					}
				}
				for i > 0 {
					i--
					stack.pop()
				}
				if opcode == 0xaf {
					if !success { // OP_CHECKMULTISIGVERIFY
						return false
					}
				} else {
					stack.pushBool(success)
				}

			case opcode >= 0xb0 && opcode <= 0xb9: //OP_NOP
				// just do nothing

			default:
				if DBG_ERR {
					fmt.Printf("Unhandled opcode 0x%02x - a handler must be implemented\n", opcode)
					stack.print()
					fmt.Println("Rest of the script:", hex.EncodeToString(p[idx:]))
				}
				return false
			}
		}

		if DBG_SCR {
			fmt.Printf("Finished Executing opcode 0x%02x\n", opcode)
			stack.print()
		}
		if stack.size()+altstack.size() > 1000 {
			if DBG_ERR {
				println("Stack too big")
			}
			return false
		}
	}

	if DBG_SCR {
		fmt.Println("END OF SCRIPT")
		stack.print()
	}

	if exestack.size() > 0 {
		if DBG_ERR {
			println("Unfinished if..")
		}
		return false
	}

	return true
}