Right now we have basic support for I2P by treating it the same as Tor (i.e., treating each connection as totally anonymous).

@mogad0n points out that i2pd has some protocol-specific support for IRC, including sending WEBIRC with a variable proxied IP value:

https://i2pd.readthedocs.io/en/latest/tutorials/irc/#running-anonymous-irc-server

https://github.com/PurpleI2P/i2pd/blob/a8e1cd9a13d14978af7a6df8e9ccded9bb8f4dd1/libi2pd_client/I2PTunnel.cpp#L448

This support is unusable as-is because it doesn't send the WEBIRC secure flag. Questions:

1. What is GetIdentHash()? Is it based on the client's cryptographic I2P address? How stable are these addresses under normal conditions? How easy are they to change (i.e., are they of any use as an anti-spam measure?)
2. Assuming the peer's I2P address has the relevant desirable properties, could we use it as an authentication mechanism (via SASL EXTERNAL, similar to a client certificate?)