If you wish to run local web services, such as CalDAV, CardDAV, WebDAV, websites, etc., you may want to connect over SSL. Here are instructions on how to generate self-signed SSL certificates, on Mac OS X that have the CA flag set to TRUE, and which will be accepted my Android devices (which are particularly fussy about how an SSL certificate is cooked up).
Hide your Mac OS X username from the login screen. It’s a simply security measure I recommend for people with laptops especially. Here’s a couple of free and easy ways to do it.
TrueCrypt remains to be the best and more trustable cross-platform disk and file encryption system. Here’s how to get it running on Yosemite and any other version of OS X
With OS X 10.9.5 Apple made some significant changes to the way Gatekeeper operates, which effectively broke many pre-Maverick (10.9.x) apps, preventing them from running. Here’s a solution.
There’s now a free and open-source way to securely encrypt calls on iPhone, and its cross compatible with Android callers too. It’s easy to install, and easy to use. Free txt messaging is on the way too. Check it out.