---
title: "Manifest and signature"
url: https://getstell.com/glossary/manifest-and-signature
description: "The two files in every PKPass that prove it is genuine; manifest.json lists a hash of every other file and signature is a detached signature over the manifest, made with the pass type ID certificate."
---

# Manifest and signature

A [PKPass](/glossary/pkpass) is a zip archive, and two files in it exist only to prove the rest has not been touched. manifest.json is a list of every other file in the bundle, [pass.json](/glossary/pass-json), the images, the localization files, each paired with a hash of its contents. The signature file is a detached cryptographic signature over the manifest, made with the private key of the program's [pass type ID certificate](/glossary/pass-type-id-certificate) and including the certificate chain up to Apple's [WWDR certificate](/glossary/wwdr-certificate).

Verification runs the chain backwards. When a pass is added, the wallet checks that the signature is valid and was made by a certificate Apple issued for the pass type identifier the pass claims, then checks that every file's hash matches the manifest. Change a single byte of pass.json, add an image, or sign with a certificate for a different identifier, and the pass is refused. That is what lets Apple Wallet accept passes from any issuer without a central registry: the certificate is the proof of ownership.

It is also why every update is a reissue. Since the whole bundle is sealed, a changed points balance means a new manifest and a new signature, which the wallet fetches through the [pass web service](/glossary/pass-web-service). Signing is fast and platforms do it thousands of times a day, but it explains why the signing certificate and key must be available to the platform, usually delivered as a [PKCS #12](/glossary/pkcs-12) file.

Most "pass will not add" reports trace back here: an expired signing certificate, the wrong WWDR generation in the chain, a file edited after the manifest was written. Google Wallet has no equivalent pair of files because a Google pass is not a file; its authenticity rests on the API call that created it and the signed [save link](/glossary/save-link) that delivers it.