Virtual Disk-Encrypted/Security on Laptop


I have been using PGPDisk and ShrinkWrap (Aladdin) in Mac OS 9 to create virtual encrypted R/W disks to hold email/diary information on my Powerbook. Neither product is OS X compatible.

Has anyone found a utility that works in Mac OS X (and OS 9 as well) that can keep disks/folders/data secure (with Read/Write access)?

[If my Powerbook is lost I need to make it difficult for anyone to recover some sections of data from my OS 9/X disks (in place encryption, so disk hacking is prevented), while still allowing multiple read/write access during bone fide sessions.]

Thanks, Rick