http://ttevhjjsjxz6uqqcjkbig5cycd7n7xv7cmd6f5fcvrqaaa7f3bj36wad.onion/technology/security/pow/index.html
¶ The PoW subsystem doesn't care where a particular request is coming from, and
because of the anonymity provided by Tor we generally don't know where requests
are coming from anyhow. We've had other DoS mitigations that try to prevent
people from entering the network and creating too many connections from too few
IPs.