Wei Dai writes:
How about a combination of the two? Suppose Alice wants to anonymously post a message and get replies. She generates a new RSA key, signs her post with it, and asks readers to send encrypted replies to a server. Then periodicly she sends a one-time reply block to the server to retrieve the accumulated replies.
I'd like to chime in and say that this is a really good idea. Basically a nymserver that holds onto incoming mail until an e-mail arrives from the nym to retrieve it. How would mixmaster be able to support one-time reply blocks? If the nym's mailbox is larger than the mixmaster message size (pretty likely) and needs to be split up, then more than one reply-block is going to be required. Should the nym generate a big stack of reply-blocks/routing headers and send them in with the retrieval request? I suppose the server could fillup as many mixmaster message parts as it had blocks, then append something like "15 more messages waiting (32,082 bytes - Two More Reply Blocks Required)" and ship it off. Reliability is a problem with remailers... what happens now if a remailer in your reply block goes out and you receive mail at your nym account? Does it just disappear? With this system you could have a simple ACK protocol to ensure reliable delivery of the mail. A magic cookie would be appended to your retrieved mail, which the server would then hold onto (it would still count against your quota...). The mail would be deleted once you sent back an ACK with the magic cookie. Here is yet another good application for DigiCash. The operator could offer free accounts with very small mailbox quotas, or charge for bigger accounts. Message retrieval could also be charged, of course. Another idea is that the sender could affix postage if they wanted their message to be appended to a full mailbox... A service like this is no different from something like pobox.com, except that this service lets you pickup your mail through e-mail instead of POP. So I don't think the operator would/should incurr any more liability for what runs through the system than pobox. andrew p.s. It would also be a cool thing, IMHO, for nym servers to bounce back an advertisement to everyone who sends mail to a nym.... A way to spread the word.