diff --git a/swh/scanner/db.py b/swh/scanner/db.py
index f071fae..0845c63 100644
--- a/swh/scanner/db.py
+++ b/swh/scanner/db.py
@@ -1,67 +1,84 @@
 # Copyright (C) 2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 """
 This module is an interface to interact with the local database
 where the SWHIDs will be saved for the local API.
 
 SWHIDs can be added directly from an input file.
 """
 
 from io import TextIOWrapper
+import logging
 from pathlib import Path
+import re
 import sqlite3
 from typing import Iterable
 
 from swh.core.utils import grouper
 
 from .exceptions import DBError
 
+# XXX copied and simplified from swh.model.identifiers (WIP), replace this in favor of
+# swh.model.identifiers.SWHID_RE when it is landed there
+SWHID_RE = re.compile("^swh:1:(ori|snp|rel|rev|dir|cnt):[0-9a-f]{40}$")
+
 
 class Db:
     """Local database interface"""
 
     def __init__(self, db_file: Path):
         self.db_file: Path = db_file
         self.conn: sqlite3.Connection = sqlite3.connect(
             db_file, check_same_thread=False
         )
 
     def close(self):
         """Close the connection to the database."""
         self.conn.close()
 
     def create_table(self, cur: sqlite3.Cursor):
         """Create the table where the SWHIDs will be stored."""
         cur.execute("""CREATE TABLE IF NOT EXISTS swhids (swhid text PRIMARY KEY)""")
 
     def add(self, swhids: Iterable[str], chunk_size: int, cur: sqlite3.Cursor):
         """Insert the SWHID inside the database."""
         for swhids_chunk in grouper(swhids, chunk_size):
             cur.executemany(
                 """INSERT INTO swhids VALUES (?)""",
                 [(swhid_chunk,) for swhid_chunk in swhids_chunk],
             )
 
+    @staticmethod
+    def iter_swhids(lines: Iterable[str]) -> Iterable[str]:
+        lineno = 0
+        for line in lines:
+            lineno += 1
+            swhid = line.rstrip()
+            if SWHID_RE.match(swhid):
+                yield swhid
+            else:
+                logging.error("ignoring invalid SWHID on line %d: %s", lineno, swhid)
+
     def create_from(
         self, input_file: TextIOWrapper, chunk_size: int, cur: sqlite3.Cursor
     ):
         """Create a new database with the SWHIDs present inside the input file."""
         try:
             self.create_table(cur)
             cur.execute("PRAGMA synchronous = OFF")
             cur.execute("PRAGMA journal_mode = OFF")
-            self.add((line.rstrip() for line in input_file), chunk_size, cur)
+            self.add(self.iter_swhids(input_file), chunk_size, cur)
             cur.close()
             self.conn.commit()
         except sqlite3.Error as e:
             raise DBError(f"SQLite error: {e}")
 
     def known(self, swhid: str, cur: sqlite3.Cursor):
         """Check if a given SWHID is present or not inside the local database."""
         cur.execute("""SELECT 1 FROM swhids WHERE swhid=?""", (swhid,))
         res = cur.fetchone()
 
         return res is not None