fix: update transport key generation to use 16-byte length and add corresponding test

repeater/data_acquisition/sqlite_handler.py

@@ -1641,13 +1641,13 @@ class SQLiteHandler:
             logger.error(f"Failed to get adverts count for contact_type '{contact_type}': {e}")
             return 0
 
-    def generate_transport_key(self, name: str, key_length_bytes: int = 32) -> str:
+    def generate_transport_key(self, name: str, key_length_bytes: int = 16) -> str:
         """
-        Generate a transport key using the proper MeshCore key derivation.
+        Generate a transport key using MeshCore-compatible key derivation.
 
         Args:
             name: The key name to derive the key from
-            key_length_bytes: Length of the key in bytes (default: 32 bytes = 256 bits)
+            key_length_bytes: Fallback random key length in bytes (default: 16)
 
         Returns:
             A base64-encoded transport key derived from the name
@@ -1655,7 +1655,6 @@ class SQLiteHandler:
         try:
             from pymc_core.protocol.transport_keys import get_auto_key_for
 
-            # Use the proper MeshCore key derivation function
             key_bytes = get_auto_key_for(name)
 
             # Encode to base64 for safe storage and transmission
@@ -1668,9 +1667,9 @@ class SQLiteHandler:
 
         except Exception as e:
             logger.error(f"Failed to generate transport key using get_auto_key_for: {e}")
-            # Fallback to secure random if MeshCore function fails
+            # Fallback to a transport-compatible random 16-byte key if derivation fails.
             try:
-                random_bytes = secrets.token_bytes(key_length_bytes)
+                random_bytes = secrets.token_bytes(16)
                 key = base64.b64encode(random_bytes).decode("utf-8")
                 logger.warning(f"Using fallback random key generation for '{name}'")
                 return key

tests/test_sqlite_handler_easy.py

@@ -1,4 +1,7 @@
+import base64
 from pathlib import Path
+import sys
+import types
 
 import pytest
 
@@ -61,6 +64,36 @@ def test_transport_key_crud_cycle(tmp_path):
     assert h.delete_transport_key(key_id) is False
 
 
+def test_generate_transport_key_uses_implicit_hashtag_region(tmp_path, monkeypatch):
+    h = _make_handler(tmp_path)
+
+    captured = {}
+    fake_transport_keys = types.ModuleType("pymc_core.protocol.transport_keys")
+
+    def _fake_get_auto_key_for(name: str) -> bytes:
+        captured["name"] = name
+        return b"0123456789abcdef"
+
+    fake_transport_keys.get_auto_key_for = _fake_get_auto_key_for
+
+    fake_protocol = types.ModuleType("pymc_core.protocol")
+    fake_protocol.transport_keys = fake_transport_keys
+
+    fake_core = types.ModuleType("pymc_core")
+    fake_core.protocol = fake_protocol
+
+    monkeypatch.setitem(sys.modules, "pymc_core", fake_core)
+    monkeypatch.setitem(sys.modules, "pymc_core.protocol", fake_protocol)
+    monkeypatch.setitem(sys.modules, "pymc_core.protocol.transport_keys", fake_transport_keys)
+
+    generated = h.generate_transport_key("eu")
+    generated_bytes = base64.b64decode(generated)
+
+    assert captured["name"] == "eu"
+    assert generated_bytes == b"0123456789abcdef"
+    assert len(generated_bytes) == 16
+
+
 def test_room_messages_and_sync_flow(tmp_path):
     h = _make_handler(tmp_path)