Before getting to the actual discussion of code signing on the iPhone, here’s an interesting tidbit I discovered while researching details about Apple’s certificates: a PDF file detailing the iPhone certificate conditions – officially, it’s a CPS (“Certification Practice Statement”). This is publicly available, and linked to from Apple’s Root Certificate Authority page, by the way.

Some interesting parts:

This CPS is applicable to the following certificates issued by the WWDR Sub-CA:

• WWDR iPhone Software Development Certificates (“Development Certificates”)

• WWDR iPhone Software Submission Certificates (“Submission Certificates”)

• WWDR CRL Certificates (“CRL Certificates”)

That means, in order, certificates for testing an application on actual iPhone/iPod Touch hardware during development; for actuallly submitting an application for publishing on the App Store; and finally, for submitting a CRL (“Certificate Revocation List”). This shows that development and publishing keys are different, as I’d thought. It remains to be seen whether the publishing keys will be applied by developers themselves before submitting their apps, or (more likely) by Apple after verifying the apps for compliance. Also, CRLs are the technical explanation for Steve Jobs’ comment that “if [developers] write a malicious app we can track them down and tell their parents”… meaning, certificates can be revoked and those apps will cease to function.

No fees are charged for this service. Digital certificates are available at no additional cost to

members of the iPhone Developers’ Program. Certificates are valid for the duration of the membership period unless otherwise revoked.

This clears up details about the $99 fee. This is an annual fee, then, for membership in the “iPhone Developer Program”, distinct from the “Mac Developer Program”. See the new http://developer.apple.com/ page, which is now split left/right between these two programs. The certificates themselves are free of charge. Elsewhere, expiration and renewal are discussed, but no actual expiration period is mentioned.

There doesn’t seem to be an equivalent document for signing Mac OS X applications, although a separate page says that you can apply to Apple for the purpose of getting your own root certificate recognized. The conditions (especially regarding auditing) appear to be much more stringent, so this looks to be directed at larger companies. Even so, there’s no fee for that either.