Encryption keys, being purely random, are not copyrightable. (In light of recent events, this raises the question of artisanal human-created keys.) Distributing keys probably violates DMCA section 1201 though.

BD+ and AACS are literally that though, that’s why VLC can’t play blu-rays.

> NB: Most commercial Blu-Ray are protected by AACS or BD+ technologies and this library is not enough to playback those discs.

https://www.videolan.org/developers/libbluray.html

clicking into the libaacs and libbd+ yields:

> NB: this project doesn't offer any key or certificate that could be used to decode encrypted copyrighted material.

Spotify's offline playback DRM hinges on a HMAC key that's a human-readable phrase, based on a certain lyric. I'm curious whether it's just a fun easter egg, or if there's some kind of legal basis for the choice.

See also https://theapplewiki.com/wiki/Dont_Steal_Mac_OS.kext