refactor: PrivateKey class signs events

README.md

@@ -49,7 +49,7 @@ time.sleep(1.25) # allow the connections to open
 private_key = PrivateKey()
 
 event = Event(private_key.public_key.hex(), "Hello Nostr")
-event.sign(private_key.hex())
+private_key.sign_event(event)
 
 relay_manager.publish_event(event)
 time.sleep(1) # allow the messages to send
@@ -116,7 +116,7 @@ event = Event(
     "Hello, NIP-26!",
     tags=[delegation.get_tag()],
 )
-event.sign(delegatee_pk.hex())
+delegatee_pk.sign_event(event)
 
 # ...normal broadcast steps...
 ```

nostr/event.py

@@ -47,11 +47,6 @@ class Event():
     def compute_id(public_key: str, created_at: int, kind: int, tags: "list[list[str]]", content: str) -> str:
         return sha256(Event.serialize(public_key, created_at, kind, tags, content)).hexdigest()
 
-    def sign(self, private_key_hex: str) -> None:
-        sk = PrivateKey(bytes.fromhex(private_key_hex))
-        sig = sk.schnorr_sign(bytes.fromhex(self.id), None, raw=True)
-        self.signature = sig.hex()
-
     def verify(self) -> bool:
         pub_key = PublicKey(bytes.fromhex("02" + self.public_key), True) # add 02 for schnorr (bip340)
         event_id = Event.compute_id(self.public_key, self.created_at, self.kind, self.tags, self.content)

nostr/key.py

@@ -7,6 +7,7 @@ from cryptography.hazmat.primitives import padding
 from hashlib import sha256
 
 from nostr.delegation import Delegation
+from nostr.event import Event
 from . import bech32
 
 
@@ -97,7 +98,10 @@ class PrivateKey:
         sk = secp256k1.PrivateKey(self.raw_secret)
         sig = sk.schnorr_sign(hash, None, raw=True)
         return sig.hex()
-    
+
+    def sign_event(self, event: Event) -> None:
+        event.signature = self.sign_message_hash(bytes.fromhex(event.id))
+
     def sign_delegation(self, delegation: Delegation) -> None:
         delegation.signature = self.sign_message_hash(sha256(delegation.delegation_token.encode()).digest())
 

test/test_relay_manager.py

@@ -26,5 +26,5 @@ def test_only_relay_valid_events():
     assert "failed to verify" in str(e)
 
     # Properly signed Event can be relayed
-    event.sign(pk.hex())
+    pk.sign_event(event)
     relay_manager.publish_event(event)