This one seemed to be quite trivial per official blog, but the whole pipeline gets a bit more complicated once the SSL enters into the game. Here is how I made it work with synergy and Ubuntu 14.04

• Configure the server and the client with the GUI application
• Make sure SSL server certificate fingerprint was stored in the ~/.synergy/SSL/Fingerprints/TrustedServers.txt
• Run sudo -su myself /usr/bin/synergyc -f --enable-crypto my.server.ip.address
• After that check everything was working with sudo /usr/bin/synergyc -d DEBUG2 -f --enable-crypto my.server.ip.address
• Finally add the greeter-setup-script=sudo /usr/bin/synergyc --enable-crypto my.server.ip.address line into the /etc/lightdm/lightdm.conf file under the [SeatDefaults] section

Why you shouldn’t do it?

Despite the convenience, there seemed to be a bit or an interference for the keyboard command and command interpretation on my side, so since my two computers side by side and since I have an usb button switch from before I got synergy, I’ve decided to manually start synergy every time I log in.