Yes, Encryptr and Crypton (the framework and server) are both fully open, in that you can run with your own server.  SpiderOak also provides a public free server.  <a href="https:&#x2F;&#x2F;github.com&#x2F;SpiderOak&#x2F;crypton" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;SpiderOak&#x2F;crypton</a> - Erin @ SpiderOak