Can you skip code signing when building specific branches?

I have uploaded the key and provisioning profile for iOS code signing using the CircleCI UI which causes the code signing credentials to be installed for every build. Is it possible to only install code signing credentials when building specific branches (e.g. only install code signing credentials for master)?

Thanks in advanced for help.

+1 to this question. I don’t need this phase at all on some builds, and it adds a lot of time to the overall duration