Certificate Pinning

What is Certificate Pinning?

Certificate Pinning is like teaching your mobile app or website to only trust specific SSL certificates, similar to how you might only accept packages from trusted delivery services. Even if someone tries to trick your app with a fake but technically valid certificate, certificate pinning ensures your app will reject it because it’s not the exact certificate you’ve told it to expect.

How Certificate Pinning Works

Certificate pinning provides an additional layer of security beyond standard certificate validation:

• Pinned Certificates: Apps store specific certificate information they expect to see
• Validation Check: Every connection verifies the certificate matches the pinned version
• Pin Types: Can pin the entire certificate, public key, or certificate authority
• Update Mechanism: Pins can be updated through app updates or remote configuration
• Backup Pins: Multiple pins prevent service disruption during certificate renewal

Implementation and Benefits

Pinning is commonly used in mobile applications, API clients, and high-security environments where additional protection against man-in-the-middle attacks is needed. While pinning provides excellent security, it requires careful management since pinned certificates must be updated when the server’s certificate changes. Improper pinning can cause app outages, so developers typically implement backup pins and graceful fallback mechanisms.