From the daily Riak Recap:
10) So check this out:
At 17:40 yesterday, solidsnack asked, “Does Riak support HTTPS?”
At 22:28, benblack made it work —>
The repo for his branch is here —> http://github.com/b/riak/tree/https
A user requested SSL support. 4 hours and 40 minutes later, it was implemented and checked in to source control. It will probably be available to the public in a short period of time.