Tor already pads packets to the same size, that is probably a large part to do with why it is not as easily fingerprinted as most VPN's. The total size of the entire stream of packets is not obfuscated though. You could try to add random padding to each page that is loaded in an attempt to obfuscate the total stream size, but I don't know how effective this will be. I think it would be better than nothing though. Another thing that you need to take into consideration is the ability for an attacker to do bidirectional fingerprinting. If they think they have identified you following a thread through SR, and then see you send 15kb of data at x time, if they see a post of that size on SR in that thread y time after they saw you send traffic, they will be pretty certain that they have identified you. The solution to this would be to pad all posts to the same size and have a random delay assigned to each post prior it to being publicly displayed. However then you are pretty much turning the forum into a cryptographic mix, and I suggest waiting for me to finish my decentralized mix forum prior to attempting to implement it yourself .