Riffle is a very interesting project and we should applaud all efforts made by engineers and researchers to make the Internet a more open and censorship-resistant place.

However, we need to note that this is not a full competitor to Tor, because:

• Riffle requires all clients to dedicate an identical amount of bandwidth (to enforce traffic-analysis-resistant anonymity): 'Moreover, each message needs to be padded to a fixed length to prevent privacy leakage through the size of the message,' and 'To be fully traffic analysis resistant, all users are required to upload a message, even if they do not wish to communicate that round'.

• Riffle is only practical for small groups of users (say 200-300) communicating with a small number of servers (2-3). The more servers that are added, the more overhead incurred as every server must receive every message.

So Riffle would be a great complement to Tor for highly sensitive communication (say journalists or whistleblowers hiding from state level actors), but would not (in its current state) be able to handle general browsing at the scale of Tor for the majority of worldwide users.