PKPASS

PKPASS is a file format for storage and exchange of digital passes developed by Apple for its Wallet application. Passes can replace physical paper or plastic cards, like a payment card, boarding pass, loyalty card or coupon.² The format specification has been published online² and this allowed for compatible implementations to be developed for other platforms like Android,³ Windows⁴ and Linux.⁵

The file is a ZIP archive with a filename extension .pkpass containing a set of digitally signed files describing the digital pass. Multiple .pkpass files can be further combined into a single ZIP archive with an extension of .pkpasses in order to combine several digital passes for ease of distribution.

The file contents of a sample PKPASS file might look like this:

icon.png is the digital pass icon. logo.png is displayed at the top left of the rendered pass.

Localized resources - like images and strings - are stored in subfolders named like this: <language_identifier>-<region_identifier>.lproj

The file pass.json is a JSON formatted dictionary describing the digital pass.

manifest.json contains a JSON dictionary containing SHA-1 hashes for all files except the manifest itself and the signature.

signature contains a PKCS #7 signature of the manifest file thus effectively signing all files in the bundle.