iOS Code Snippet SSL Certificate Pinning

Certificate pinning is a security feature. When set, the app will only accept the listed, per-domain, certificates. This is usually not needed as certificates must have a valid certificate chain up to the trusted root.
Starting from iOS 14 it is quite simple to add certificate pinning.
Full information: https://developer.apple.com/news/?id=g9ejcf8y

Steps:

1. Download the intermediate or root certificate PEM file. In Firefox it looks like this:


2. Install OpenSSL: https://slproweb.com/products/Win32OpenSSL.html

3. Run: cat ca.pem | openssl x509 -inform pem -noout -outform pem -pubkey | openssl pkey -pubin -inform pem -outform der | openssl dgst -sha256 -binary | openssl enc -base64

4. Add the following code to the main module. Replace the domain and the base64 key.

Example:

You can test it by changing the domain to a different one and then make a a request to the new domain.