Due to Australia being such a large country and our broadband not being the fastest, it is often more efficient to deliver materials via courier. When working on a film which is undisclosed, often Hard drives containing picture files and audio files are transported from one place to another. If the contents of these drives were to fall in to the wrong hands than many millions of dollars could be potentially lost due to piracy etc etc. One way to combat this is to Encrypt all files and/ or all drives. The Mac OS includes encryption as part of it's drive set up. Another option is Truecrypt . The differences being: The Mac OS will only encrypt Disk Images on a drive, whereas Truecrypt will encrypt an entire volume. The Mac OS version also needs to do an encryption pass which takes time, whereas Truecrypt encrypts on the fly.
A quick way to encrypt files using Disk Utility, is to create a blank disk image on your desktop using encryption. Then just copy straight into the image.