LinuxQuestions.org - Installing a crypto file system on Slackware

I have looked all over the internet and can't seem to find a way to get this going. I am sure I am overlooking something simple... but I just can't find away to get it going.

I have installed Slackware from the boxed CD set, version 10.0
I upgraded the kernel to 2.6.10.
I'm not sure that it matters, but I also upgraded to Xorg 6.8.1 and KDE 3.3.2.

This is all on a laptop and I need a crypto file system in case the computer gets stolen.

It seems to come down to needing a program called dmsetup. From what I understand that comes with the 2.6 kernel, however I cannot seem to find it in any of my Slackware parititions. I have looked at the util-linux and installed them inspite of the warnings, that did not seem to help.

I also installed Slackware 10.1 in a separate file-system. I could not get the it work there as well.

I have even RTFM on crypto, but cannot seem to find the one step I need to make it work.

I have followed several FAQ and how to's but I keep running into a brick wall.

Can someone help me, or point me to a FAQ or how-to for getting a crypto file system going under slackware?

TIA.

-JJ