txscript/script.go

@@ -66,11 +66,7 @@ func isScriptHash(pops []parsedOpcode) bool {
 // IsPayToPubKey returns true if the script is in the standard pay-to-pubkey
 // (P2PK) format, false otherwise.
 func IsPayToPubKey(script []byte) bool {
-	pops, err := parseScript(script)
-	if err != nil {
-		return false
-	}
-	return isPubkey(pops)
+	return isPubKeyScript(script)
 }
 
 // IsPayToScriptHash returns true if the script is in the standard

txscript/standard.go

@@ -85,6 +85,64 @@ func (t ScriptClass) String() string {
 	return scriptClassToName[t]
 }
 
+// extractCompressedPubKey extracts a compressed public key from the passed
+// script if it is a standard pay-to-compressed-secp256k1-pubkey script.  It
+// will return nil otherwise.
+func extractCompressedPubKey(script []byte) []byte {
+	// A pay-to-compressed-pubkey script is of the form:
+	//  OP_DATA_33 <33-byte compressed pubkey> OP_CHECKSIG
+
+	// All compressed secp256k1 public keys must start with 0x02 or 0x03.
+	if len(script) == 35 &&
+		script[34] == OP_CHECKSIG &&
+		script[0] == OP_DATA_33 &&
+		(script[1] == 0x02 || script[1] == 0x03) {
+
+		return script[1:34]
+	}
+
+	return nil
+}
+
+// extractUncompressedPubKey extracts an uncompressed public key from the
+// passed script if it is a standard pay-to-uncompressed-secp256k1-pubkey
+// script.  It will return nil otherwise.
+func extractUncompressedPubKey(script []byte) []byte {
+	// A pay-to-uncompressed-pubkey script is of the form:
+	//   OP_DATA_65 <65-byte uncompressed pubkey> OP_CHECKSIG
+	//
+	// All non-hybrid uncompressed secp256k1 public keys must start with 0x04.
+	// Hybrid uncompressed secp256k1 public keys start with 0x06 or 0x07:
+	//   - 0x06 => hybrid format for even Y coords
+	//   - 0x07 => hybrid format for odd Y coords
+	if len(script) == 67 &&
+		script[66] == OP_CHECKSIG &&
+		script[0] == OP_DATA_65 &&
+		(script[1] == 0x04 || script[1] == 0x06 || script[1] == 0x07) {
+
+		return script[1:66]
+	}
+	return nil
+}
+
+// extractPubKey extracts either compressed or uncompressed public key from the
+// passed script if it is a either a standard pay-to-compressed-secp256k1-pubkey
+// or pay-to-uncompressed-secp256k1-pubkey script, respectively.  It will return
+// nil otherwise.
+func extractPubKey(script []byte) []byte {
+	if pubKey := extractCompressedPubKey(script); pubKey != nil {
+		return pubKey
+	}
+	return extractUncompressedPubKey(script)
+}
+
+// isPubKeyScript returns whether or not the passed script is either a standard
+// pay-to-compressed-secp256k1-pubkey or pay-to-uncompressed-secp256k1-pubkey
+// script.
+func isPubKeyScript(script []byte) bool {
+	return extractPubKey(script) != nil
+}
+
 // isPubkey returns true if the script passed is a pay-to-pubkey transaction,
 // false otherwise.
 func isPubkey(pops []parsedOpcode) bool {