https://darkdot.com/articles/tor-ddos-leads-to-proof-of-work/

Their PoW algorithm was built by the same main developer as that of Monero (RandomX) and shares many similarities:

github.com/tevador/equix

Very excited to see this built out as it poses the most promising fix for the ongoing attack against the Tor network. The current (WIP) merge request for PoW support in Tor can be followed here:

https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/702