[mikeash]

The key long predates any licensing deals. In fact, the system used for licensing is different from the one that the key in question applies to. The AirTunes/AirPlay system has changed over the years, and the key that was extracted is for an older (but still supported) system than in used for third-party licensees.

I don't see how it would be covered by the DMCA like DeCSS is, as the encryption is not for a DRM system.

Even if it is, well, I think most of us will agree that cracking encryption for the purposes of circumventing DRM for legitimate purposes should be allowed. But of course that gets us into discussions of how things are versus how things should be.