How to sign a .pkpass file correctly

Create a Pass Type ID in the Apple Developer portal and issue a certificate for it. The certificate common name and Pass Type ID extension identify the pass type it may sign, while the organizational unit identifies your Team ID. Those values must agree with passTypeIdentifier and teamIdentifier in pass.json.

Export the private key and certificate into a format your signing environment can use. Protect the private key as a production secret: do not bundle it in an app, commit it to source control, or send it to a browser client.

Hash every file that belongs to the pass except manifest.json and signature. Keys are relative archive paths, including localization directories. Values are lowercase hexadecimal SHA-1 digests of the raw file bytes.

Generate the manifest deterministically so the same input files yield the same JSON bytes and signature. Do not rewrite, pretty-print, or normalize manifest.json after signing; the signature covers its exact bytes.

Create a detached CMS/PKCS#7 signature over manifest.json. The signature payload should include the signer certificate and WWDR intermediate so a verifier can resolve the chain without guessing which intermediate was used.

The resulting binary file is named signature with no extension. A successful signing command is not enough: immediately verify the signature against the manifest and inspect the embedded certificates, signing time, identity fields, and validity dates.

ZIP the pass files themselves, not their parent directory. Preserve case-sensitive filenames and avoid macOS metadata such as __MACOSX and .DS_Store. The final extension is .pkpass, but the internal format remains a ZIP archive.

A complete verifier should recompute every manifest hash, ensure referenced files exist, verify the detached signature, validate certificate dates and the WWDR chain, and compare Team ID and Pass Type ID values with pass.json. Only after those checks pass should the file be distributed.