Proof-of-work for exit remailers
To prevent spam and/or floods originating from the mixminion network it might be sensible to require (adjustable by the exit remailer operator) some proof-of-work, e.g. hashcash before relaying the message. Dummy messages would not be affected because those don't leave the network anyway.
[Automatically added by flyspray2trac: Operating System: All]