Blogger API Update

Steve Jenson has responded to many of my concerns regarding the Blogger API. He plans to change field names incompatible with the metaWeblog API to be compatible; he's changing the method name prefix to blogger2 (which will aid non-Blogger server implementations); he'll be changing getRecentPosts to getPosts for clarity; he'll be adding an offset parameter to the search filter struct.

Steve also posted his thoughts on a security mechanism. I'm not sure that the overhead required for the forward-secrecy he describes is worthwhile, necessarily, considering that most API transactions are fairly brief and don't involve many messages passed back and forth (the more messages, the better chance for an attacker to break the key).

I agree on the use of Diffie-Hellman, though. Perhaps a simpler scheme would be similar to SSH-2 key exchange: one DH key exchange, producing one shared secret, which can be broken up into two symmetric keys: one for client-to-server communication, the other for server-to-client. Any sensitive information in the XML-RPC request/response is then encrypted using a symmetric cipher and the corresponding key. Since the transaction generally wouldn't involve that many messages, there's not much ciphertext to work with when trying to break the encryption. It's possible that a rekey() method could be implemented to renegotiate the shared secret, and mandated that any transaction lasting longer than a certain period of time rekey at specified intervals.