looking for Arduino MQTT library w/ encryption (SSL or TLS?)

Hi,
I've been playing with the knolleary MQTT library for Arduino. It works great, but it doesn't seem to support any type of SSL or TLS encryption. Is there one that does, or is encryption computationally complex for the Arduino?

Thanks!

Atleast the 8-bit Arduinos don't have enough resources for SSL or TLS implementation.