GCM on the other hand took me a gazillion tries, and even though I ended up more or less copying a reference implementation I still got weird edge case errors.
US7949129B2 expired because he didn't pay the patent fees. US8321675B2 claims priority to a patent from 2001. Claiming priority is a way to broaden an existing patent by saying “it's this, but improved”; however, this also means inheriting the expiry date of the patent claiming priority to. So yeah, that one's expiring next year already. Holy cow, thanks for making me check.
Another, related patent that he notes in the FAQ[1] is 8,107,620, which won't expire until 2029 unless IBM forgets to pay patent fees. Hard to tell if it really applies to OCB3 though.
[1] https://www.cs.ucdavis.edu/~rogaway/ocb/ocb-faq.htm#patent:p...
So, 2021 might be the year!
Edit: I was incorrect about the Jutla patent. It seems to only apply to patents that are CBC- or ECB-like. GCM should be fine.