For your security, Apple devices only run code that's been properly signed. This isn't a quick process however, and if you have many cocoapod frameworks in your project that all need signing, you can find your build time bloating to a painful several minutes.
Fortunately, the cocoapods-1.2.0 beta features the option to enable parallel code signing, which should increase your build time dramatically.
You can install the beta by running:
gem install cocoapods --pre
Once you've got that installed, you simply need to add a variable to your Build Settings:
Set COCOAPODS_PARALLEL_CODE_SIGN to true.
Now when you build your application, your cocoapods will code-sign a lot quicker.