Doing a fast search it seems that there’s no problem to have it in Linux (as far as you’ve the right versions).
Kernel newer than 2.6.19 (like zeroshell) should have support build in:
http://www.logix.cz/michal/devel/padlock/
Portable openssh has support too:
https://bugzilla.mindrot.org/show_bug.cgi?id=1437
Openssl 0.9.8e should have it included too (lenny’s version is 0.9.8g)
So have a look to the versions on zeroshell, and please post the results