1) The same as in a two-user chatroom? To hide the conversation content from everyone outside of the chatroom? 2) I heard people work on that, but I don't know any details. Might take a bunch of pairwise exchanges [tedious, but probably okay for small rooms], or moderators may serve as trust/key exchange hubs.

Secure chat among several parties that trust each other. Doesn't really matter if n=2 or n=5.

As for 2), one trivial solution would be to stimulate "true" multi user chat by simply having n x n regular 2-party chats merged into a single view. Should scale for most reasonable chat room sizes.

OTR can support XMPP. The client must implement OTR or allow for plugins, hence my original question. http://wiki.xmpp.org/web/OTR

Considering it is javascript based, I could extend it to support it if I truly wanted to.

> 1) what is the point of OTR in a multi-user chatroom?

I'd assume that Candy works nicely with single-user chats too.