adds a separate representation for a detached signature

lbrynet/schema/signature.py

@@ -0,0 +1,24 @@
+# Flags
+LEGACY = 0x80  # Everything is contained in the protobuf.
+NAMED_SECP256K1 = 0x01  # ECDSA SECP256k1 64 bytes. Claim name is also signed.
+
+
+class Signature:
+
+    def __init__(self, raw_signature: bytes, certificate_id: bytes, flag: int=NAMED_SECP256K1):
+        self.flag = flag
+        assert len(raw_signature) == 64, f"signature must be 64 bytes, not: {len(raw_signature)}"
+        self.raw_signature = raw_signature
+        assert len(certificate_id) == 20, f"certificate_id must be 20 bytes, not: {len(certificate_id)}"
+        self.certificate_id = certificate_id
+
+    @classmethod
+    def flagged_parse(cls, binary: bytes):
+        if binary[0] == NAMED_SECP256K1:
+            return binary[85:], cls(binary[1:65], binary[65:85], NAMED_SECP256K1)
+        else:
+            return binary, None
+
+    @property
+    def serialized(self):
+        return (bytes([self.flag]) + self.raw_signature + self.certificate_id) if self.flag != LEGACY else b''