Handle decryption failures when syncing index

src/password_manager/encryption.py

@@ -223,15 +223,28 @@ class EncryptionManager:
             return fh.read()
 
     def decrypt_and_save_index_from_nostr(
-        self, encrypted_data: bytes, relative_path: Optional[Path] = None
-    ) -> None:
-        """Decrypts data from Nostr and saves it, automatically using the new format."""
+        self,
+        encrypted_data: bytes,
+        relative_path: Optional[Path] = None,
+        *,
+        strict: bool = True,
+    ) -> bool:
+        """Decrypts data from Nostr and saves it.
+
+        Parameters
+        ----------
+        encrypted_data:
+            The payload downloaded from Nostr.
+        relative_path:
+            Destination filename under the profile directory.
+        strict:
+            When ``True`` (default) re-raise any decryption error. When ``False``
+            return ``False`` if decryption fails.
+        """
         if relative_path is None:
             relative_path = Path("seedpass_entries_db.json.enc")
         try:
-            decrypted_data = self.decrypt_data(
-                encrypted_data
-            )  # This now handles both formats
+            decrypted_data = self.decrypt_data(encrypted_data)
             if USE_ORJSON:
                 data = json_lib.loads(decrypted_data)
             else:
@@ -240,18 +253,22 @@ class EncryptionManager:
             self.update_checksum(relative_path)
             logger.info("Index file from Nostr was processed and saved successfully.")
             print(colored("Index file updated from Nostr successfully.", "green"))
-        except Exception as e:
-            logger.error(
-                f"Failed to decrypt and save data from Nostr: {e}",
-                exc_info=True,
-            )
-            print(
-                colored(
-                    f"Error: Failed to decrypt and save data from Nostr: {e}",
-                    "red",
+            return True
+        except Exception as e:  # pragma: no cover - error handling
+            if strict:
+                logger.error(
+                    f"Failed to decrypt and save data from Nostr: {e}",
+                    exc_info=True,
                 )
-            )
-            raise
+                print(
+                    colored(
+                        f"Error: Failed to decrypt and save data from Nostr: {e}",
+                        "red",
+                    )
+                )
+                raise
+            logger.warning(f"Failed to decrypt index from Nostr: {e}")
+            return False
 
     def update_checksum(self, relative_path: Optional[Path] = None) -> None:
         """Updates the checksum file for the specified file."""

src/password_manager/manager.py

@@ -1103,8 +1103,10 @@ class PasswordManager:
                     encrypted = deltas[-1]
             current = self.vault.get_encrypted_index()
             if current != encrypted:
-                self.vault.decrypt_and_save_index_from_nostr(encrypted)
-                logger.info("Local database synchronized from Nostr.")
+                if self.vault.decrypt_and_save_index_from_nostr(
+                    encrypted, strict=False
+                ):
+                    logger.info("Local database synchronized from Nostr.")
         except Exception as e:
             logger.warning(f"Unable to sync index from Nostr: {e}")
         finally:
@@ -1195,14 +1197,12 @@ class PasswordManager:
                     deltas = asyncio.run(self.nostr_client.fetch_deltas_since(version))
                     if deltas:
                         encrypted = deltas[-1]
-                try:
-                    self.vault.decrypt_and_save_index_from_nostr(encrypted)
+                success = self.vault.decrypt_and_save_index_from_nostr(
+                    encrypted, strict=False
+                )
+                if success:
                     logger.info("Initialized local database from Nostr.")
                     have_data = True
-                except Exception as err:
-                    logger.warning(
-                        f"Failed to decrypt Nostr data: {err}; treating as new account."
-                    )
         except Exception as e:
             logger.warning(f"Unable to sync index from Nostr: {e}")
 

src/password_manager/vault.py

@@ -60,9 +60,13 @@ class Vault:
         """Return the encrypted index bytes if present."""
         return self.encryption_manager.get_encrypted_index()
 
-    def decrypt_and_save_index_from_nostr(self, encrypted_data: bytes) -> None:
+    def decrypt_and_save_index_from_nostr(
+        self, encrypted_data: bytes, *, strict: bool = True
+    ) -> bool:
         """Decrypt Nostr payload and overwrite the local index."""
-        self.encryption_manager.decrypt_and_save_index_from_nostr(encrypted_data)
+        return self.encryption_manager.decrypt_and_save_index_from_nostr(
+            encrypted_data, strict=strict
+        )
 
     # ----- Config helpers -----
     def load_config(self) -> dict:

src/tests/test_index_import_export.py

@@ -63,7 +63,7 @@ def test_index_export_import_round_trip():
                 },
             }
         )
-        vault.decrypt_and_save_index_from_nostr(encrypted)
+        assert vault.decrypt_and_save_index_from_nostr(encrypted)
 
         loaded = vault.load_index()
         assert loaded["entries"] == original["entries"]

src/tests/test_profiles.py

@@ -6,6 +6,9 @@ sys.path.append(str(Path(__file__).resolve().parents[1]))
 
 from utils.fingerprint_manager import FingerprintManager
 from password_manager.manager import PasswordManager, EncryptionMode
+from helpers import create_vault, dummy_nostr_client
+import gzip
+from nostr.backup_models import Manifest, ChunkMeta
 
 
 VALID_SEED = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
@@ -51,3 +54,33 @@ def test_add_and_switch_fingerprint(monkeypatch):
         assert pm.current_fingerprint == fingerprint
         assert fm.current_fingerprint == fingerprint
         assert pm.fingerprint_dir == expected_dir
+
+
+def test_sync_index_missing_bad_data(monkeypatch, dummy_nostr_client):
+    client, _relay = dummy_nostr_client
+    with TemporaryDirectory() as tmpdir:
+        dir_path = Path(tmpdir)
+        vault, _enc = create_vault(dir_path)
+
+        pm = PasswordManager.__new__(PasswordManager)
+        pm.fingerprint_dir = dir_path
+        pm.vault = vault
+        pm.nostr_client = client
+        pm.sync_vault = lambda *a, **k: None
+
+        manifest = Manifest(
+            ver=1,
+            algo="aes-gcm",
+            chunks=[ChunkMeta(id="c0", size=1, hash="00")],
+            delta_since=None,
+        )
+        monkeypatch.setattr(
+            client,
+            "fetch_latest_snapshot",
+            lambda: (manifest, [gzip.compress(b"garbage")]),
+        )
+        monkeypatch.setattr(client, "fetch_deltas_since", lambda *_a, **_k: [])
+
+        pm.sync_index_from_nostr_if_missing()
+        data = pm.vault.load_index()
+        assert data["entries"] == {}