About BitTorrent sync,
BitTorrent sync (or btsync as it is now branded) is a very powerfull tool to sync large amounts of data between desktop, mobile and server like devices.
It uses the bit torrent protocol for data transfer but is secured in a way only the people/devices which you share the key with can download/acces or alter your data.
There is a pro version available but in my opinion the free version is good enough for personal use, the only thing extra the pro version adds is more rights/authorization options for a multi user environment.
Installing
Add package signing key of Silvenga, a developer who maintains a reasonably up to date Ubuntu repository for Btsync (check out his github here):
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 992A3C9A3C3DE741
Add the btsync repository:
add-apt-repository "deb http://deb.silvenga.com/btsync any main"
apt-get update
Install btsync
apt-get install btsync
After following the prompts, open your browser to http://SERVERIP:8888/gui/
(if using the default configuration).
Furthermore, by default the WEBUI uses the key and certificate that are found her /etc/btsync/debconf-default.key
Private key:/etc/btsync/debconf-default.key
Certificate: /etc/btsync/debconf-default.crt
if you replace these files with your own certificate and key ssl should shart working as expected on its own, if not try restarting btsync by executing: service btsync restar