I just published a Swift package for developers who need to create CMS (Cryptographic Message Syntax) signatures in iOS/macOS apps using OpenSSL under the hood.
CMS signing is widely used in secure email (S/MIME), digital document signing (PDF), and many enterprise-level protocols — and yet it’s rarely supported out of the box in Swift.
With SwiftCMSSigner, you can now generate detached, base64-encoded CMS signatures using a simple, modular Swift API. No external tools. No hacks. Just clean integration via Swift Package Manager.

Check it out on GitHub:
https://github.com/smsdm4/SwiftCMSSigner