Encryption of user data on redhat 5 and 6

[Yard, John]

I am researching encryption of user data on redhat.

Rh Enterprise 5/6 would be the levels.

The encryption/dycryption  of user data  on disk must be 
dynamic and transparent to both ftp and ssh sessions,
no special commands to encrypt/decrypt user data. Everything
is scripted, no user intervention.  

Would like to encrypt/decrypt on a directory driven basis 
vs a filesystem basis , but this is not an absolute requirement. 

The filesystems are mounted. Mapping user to filesystem
is problematic , because there are +300 users , and 
am not sure how this would scale up .

Ideas ? Suggestions/ 

Thks,

JYard
UCLA