IPA files – Apple’s proprietary format for archive files for Iphone Ipod Touch and Ipad applications – Uses Apple’s FairPlay DRM technology


When we download I-Phone, Ipad and IPod Touch apps from the Apple store, we are actually downloading IPA files, which is Apple’s proprietary format for archive files that contains the binary code used by the “I” family of products from Apple

As an analogy, think of the IPA file as a “zip” file used in the Apple realm.

Apple created the ITunes and App Store to control and manage the deployment of all  products for the “I” family.

So, how can “jailbroken” devices install  “I” apps?

The answer lies on an obscure command:

zip -0 -y -r myAppName.ipa Payload/

This unsigned, unofficial .ipa file can be created by some smart re-engineering efforts as follows:

1. You first copy the file with the extension .app from the Products folder of the application called Xcode to a folder called Payload

2. Compress the file located in Payload by using the zip command described above

3. This “new” unsigned, unofficial .ipa file can now be installed on jailbroken devices

4. There is a thrid party software called Appsync that allows such maneuver.

But, what is so unique about the .ipa file?

The .ipa file has a built-in structure that  iTunes and AppStore understand and certify . The jailbroken version doesn’t have such “certification”.

The .ipa file contains the following files:

appname.app. It is the binary (or executable)  file for the app

iTunes Artwork file.  It is a PNG image (containing the app’s icon for showing the app in iTunes and the App Store)

iTunesMetadata.plist.  It is a editable file (you can use TextEdit to open it) that contains information such as the copyright information, the release date, the purchase date, the name of the developer and company who created it, etc. Think of it as an “Help-About” used in the WinTel world

See below a good example of the structure of an “official” .ipa file:

/Payload/
/Payload/Application.app
/iTunesArtwork
/iTunesMetadata.plist

See below some great links that help complement the information provided here:

Special “Thanks” to Wikipedia for providing a great detailed explanation of the .ipa file

Xcode

iTunesMetadata.plist

.APP

TextEdit

Fair Play DRM technology

Xcode Glossary:

Xcode: It is Apple’s integrated development environment for creating apps for the iPhone, Ipad, IPod and Mac.

Xcode includes the Xcode IDE, instruments, iOS Simulator, the latest Mac OS X and iOS SDKs (software development kits)

“An .ipa file is an iPhone application archive file which stores an iPhone app. It is usually encrypted with Apple‘s FairPlay DRM technology. Each .ipa file is compressed with a binary for the ARM architecture and can only be installed on an iPhone, iPod Touch, or iPad. Files with the .ipa extension can be uncompressed by changing the extension to .zip and unzipping.
.ipa files cannot be installed on the iPhone Simulator because they do not contain a binary for the x86 architecture. To run applications on the simulator, original project files which can be opened using the Xcode SDK are required.”  (from Wikipedia )

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3 Responses to “IPA files – Apple’s proprietary format for archive files for Iphone Ipod Touch and Ipad applications – Uses Apple’s FairPlay DRM technology”

  1. Joet Johnson Says:

    In this 3g era really people need the iPhone wich is a line of Internet- and multimedia-enabled smartphones designed and marketed by Apple.Nice content.Keep sharing more information on this content.

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