HotStuff: BFT Consensus in the Lens of Blockchain (arXiv: 1803.05069v6 [CS.DC]), Algorithms 4 and 5.
This is my first try at writing a non-trivial spec, so constructive criticism is very welcome.
You can find it here https://github.com/ausimnull/EDHotStuff
I hope this may be of interest to some of the community, as HotStuff is currently gaining a lot of attention.
best regards
Steve (ausimnull)