http://bbs.espressif.com/viewtopic.php?f=21&t=389
hopefully someone can port it to the SDK
EDIT :
Looking at this githib issue https://github.com/esp8266/Arduino/issues/43 it might be that the standard Arduino SDK supports SSL!!!
Give it a whirl and let us know
It is not in the Arduino-based SDK yet.
Depending on your point release of the IoT SDK, and whether you patched libssl, and what SSL handshake your server supports, you MIGHT be able to connect via SSL.
However, libssl is based on AxTLS, and AxTLS caps out at TLSv1.1 - and TLSv1.2 is the current/modern version. "Luckily" lots of popular devices and browsers require TLSv1.1 so you're ok for now.