Suggestions? Password & Encrypted Read/Write File like a Mac (.dmg or .SparseBundle) also R/W on Windows, Ubuntu

Question

For years I have used .dmg or .sparsebundle (Encrypted and Password Protected) to safely keep home directory backups on my Mac.

Now, I am looking for a similar Full Permissions/Read/Write that maintains an encrypted, and password protected file that it Tri-Platform. I'd like to have the future ability to use it on Mac OS X, Windows 7/8, and Ubuntu (current releases+).

I appreciate your recommendations. Thank you.

(I like mounting a DMG and having a file directory structure that can be easily maintained and organized. When done, un-mounting the file.)

(I've seen Windows tools to open encrypted DMG files? and I will explore these options, but with the desire to also keep the file accessible on on three OSes, someone might have additional suggestions.)

Answer 1

You should have a look at TrueCrypt which is OpenSource, free and available for OS X, Linux and 7/Vista/XP/2000 alike.