document that nonce-based authentication is for the future

[hippotat] / PROTOCOL

Server maintains a queue of outbound packets for each user

Packets which are older than the applicable max_queue_time are discarded

Each incoming request to the server takes up to max_batch_down bytes
from the queue and returns them as the POST response body payload

Each incoming request contains up to max_batch_up bytes of payload.
It's a multipart/form-data.

Authentication: for now, plaintext password

Routing assistance: none in hippotat; can be requested on client
 from userv-ipif via `vroutes' parameter.  Use with secnet polypath
 ideally uses the special support in secnet 0.4.x.

Client form parameters (multipart/form-data):
 m		metadata, newline-separated list (text file) of
			client ip address (textual)
		       	password
			target_requests_outstanding
			http_timeout
 d              data (SLIP format, with SLIP_ESC and `-' swapped)




Possible future nonce-based authentication:

server keeps big nonce counter for each client
meaning is:
 nonce counter is most recent nonce client has sent
also server keeps bitmap of the previous ?64 nonces,
 whether client has sent them

client picks.... xxx