Since iOS apps are encrypted by Apple's FairPlay DRM, unencrypted versions are not available for download via third-party app stores. To view the contents of an iOS app, it must be first decrypted and extracted. Although encrypted IPA files can be downloaded directly from iTunes, it is a manual process to decrypt the app manually using tools like otool, lldb, and dd. Thankfully, this process has been automated using a tool known as Clutch2.
Dumpdecrypted is another tool that can be used to dump decrypted iOS applications to a file, but will not be used in this chapter. Dumpdecrypted can be found via the repository at https://github.com/stefanesser/dumpdecrypted.
For this recipe, otool will be used, which is included with XCode's command-line tools. Installing XCode command-line tools can be accomplished by executing the following command in an OS X terminal:
$ xcode-select -install
Clutch2 will be used to decrypt applications. Clutch2 can be downloaded...