IPA file cannot be zipped

[bojanin]

Hello,

I used BFinject to decrypt the twitter app as a test. I then transferred the decrypted ipa to my laptop using the tutorial provided. I tried to make the extension a .zip to unzip it but then it turns into a .cpgz. So i tried to run "class-dump -H twitter.ipa" and I get the error: class-dump: Input file (twitter.ipa) is neither a Mach-O file nor a fat archive. I tried this with other apps and the same things happen. Im just trying to load the ipa into ida-pro.

Anything will help, thanks.