I've been reading this PDF on reverse-engineering iOS applications and have reached slide 39, decrypting the binary. However, I've been attempting to disassemble and explore the binary in OS X 10.9.5 rather than iOS, since my phone is not jailbroken and I'd prefer not to do so.
I downloaded the IPA file from the App Store by using a forward proxy running locally on my laptop to intercept the download request on my iPhone and replicate it on my laptop. From there I followed these directions to extract the encrypted binary from the IPA file, and used the directions from the PDF file to check whether it was encrypted. I confirmed that it was encrypted because the output from
Load command 11 cmd LC_ENCRYPTION_INFO cmdsize 20 cryptoff 8192 cryptsize 15187968 cryptid 1
Is there a way to decrypt the DRM using only my Apple computer?