Format + Encryption on external hard drive for Win/Mac/Linux

[IparryU]

I have a 1 TB external HDD and I need it to be able to work on all types of OS. It is NTSF now, so I cannot get things off a Mac. I also need to encrypt it.

so:
1. What format should I use so it will work on Windoze, Mac, and Linux?
-Some files are larger than 4 GB, so FAT wont work.

2. Regarding encryption, what is the easiest way to go about this?
-Software recommendations?
-Will it work across different OS's?

3. I Googled some guides up and got mixed results, I figured someone here could give a better response.