fixup! feat(core): add nostr

common/protob/messages-nostr.proto

@@ -10,7 +10,7 @@ import "options.proto";
 /**
  * Request: Ask the device for the Nostr public key
  * @start
- * @next NostrMessageSignature
+ * @next NostrPubkey
  */
 message NostrGetPubkey {
     repeated uint32 address_n = 1; // used to derive the key
@@ -31,24 +31,28 @@ message NostrTag {
     // Nostr tags consist of at least one string (the key)
     // followed by an arbitrary number of strings,
     // the first of which (if present) is called "value".
-    // See: NIP-01 https://github.com/nostr-protocol/nips/blob/master/01.md#tags
+    // See NIP-01: https://github.com/nostr-protocol/nips/blob/master/01.md#tags
     required string key = 1;
     optional string value = 2;
     repeated string extra = 3;
 }
 
 /**
- * Request: Ask device to sign event
+ * Request: Ask device to sign an event
  * @start
  * @next NostrEventSignature
  * @next Failure
  */
 message NostrSignEvent {
-    repeated uint32 address_n = 1; // used to derive the key
-    required uint32 created_at = 2;
-    required uint32 kind = 3;
-    repeated NostrTag tags = 4;
-    required string content = 5;
+    repeated uint32 address_n = 1;   // used to derive the key
+
+    // Nostr event fields, except the ones that are calculated by the signer
+    // See NIP-01: https://github.com/nostr-protocol/nips/blob/master/01.md
+
+    required uint32 created_at = 2;  // Event created_at: unix timestamp in seconds
+    required uint32 kind = 3;        // Event kind: integer between 0 and 65535
+    repeated NostrTag tags = 4;      // Event tags
+    required string content = 5;     // Event content: arbitrary string
 }
 
 /**

core/src/apps/nostr/sign_event.py

@@ -44,11 +44,17 @@ async def sign_event(msg: NostrSignEvent, keychain: Keychain) -> NostrEventSigna
     await confirm_value(
         title, content, "", "nostr_sign_event", info_items=[("", tags_str)]
     )
+
+    # The event ID is obtained by serializing the event in a specific way:
+    # "[0,pubkey,created_at,kind,tags,content]"
+    # See NIP-01: https://github.com/nostr-protocol/nips/blob/master/01.md
     serialized_tags = ",".join(
         ["[" + ",".join(f'"{t}"' for t in tag) + "]" for tag in tags]
     )
     serialized_event = f'[0,"{hexlify(pk).decode()}",{created_at},{kind},[{serialized_tags}],"{content}"]'
     event_id = sha256(serialized_event).digest()
+
+    # The event signature is basically the signature of the event ID computed above
     signature = secp256k1.sign(sk, event_id)[-64:]
 
     return NostrEventSignature(pubkey=pk, id=event_id, signature=signature)