So, Security and CommonCrypto were already open source. The new thing here is corecrypto - but it has not been made open source! If you click the download link, you get a license agreement authorizing you to use it only "for the sole purpose of verifying the security characteristics and correct functioning of the Apple Software".

I don't really understand the point of not just publishing it under a regular open source license, since it's hardly some big competitive advantage for Apple when there are plenty of other libraries to do the same thing.

Still, nice to be able to audit it.