There is Unison[1] which can sync across computers across networks and across OSes (Windows ,Linux, etc). It is open-source (GPL-licensed ) and trivial to setup. The transfer connections can be tunneled over encrypted SSH.
I have been using it for a while and it works well for the set of requirements you have noted.
On Thu, Nov 7, 2013 at 6:31 PM, Eggert, Lars <lars@xxxxxxxxxx> wrote:
Hi,
On 06 Nov 2013, at 12:41, Russ Housley <housley@xxxxxxxxxxxx> wrote:
> 5. Many insecure protocols are used in the Internet today, and the IETF should create a secure alternative for the popular ones.
since a "secure DropBox alternative" was brought up: the pieces for building such do exist, but some exist outside the IETF. For example, SNIA's CDMI (http://www.snia.org/cdmi) could be useful, and on the IETF side we have of course WebDAV.
In many cases, the reason that such alternatives don't exist probably isn't because there aren't any open protocols available to build them with, it's that the proprietary services have polished clients that are simple to set up, available for many clients, and that they have a robust and well-managed backend. There's not much the IETF can do about these factors.
In the specific case of DropBox clones, several vendors of storage systems (incl. my employer) are making or will shortly be making mobile clients available that use said storage systems as a backend instead of the public cloud. So at least for that particular application, there are alternatives available.
Lars