Actually, as far as I know, ksecurity is mostly a "behind the scene" package from SunLab. It is used to provide transparent support for https (mostly). So, you do not really need to know the details about it. Just use "https://" in your URL and it will automatically be invoked. I do not think Sun has any public documentation support for ksecurity/kssl. But if you find any, let me know!
Actually, it is not part of the public APIs listed in MIDP 2.0 draft 7 ...
Have a look at this presentation:
http://www.sun.com.sg/events/presentation/files/j2me_techbriefing/Preso_Peter_WirelessSecurity.pdf