Encrypting USB external harddrive
I bought a 500GB Western Digital external harddrive today. I would like to create one huge ext3 partition on it and use it for file storage. However, I would like to use some sort of encryption (I don't want anyone else to be able to access the data I will be storing on it). I know absolutely nothing about encryption that could help me right now. These are some questions
· HOW do I encrypt my drive???
· Should I encrypt the partition before putting any data on it, or can a full encryption be enforced even after data has been stored (meaning all the data on it would get encrypted)
· What are my choices of encryption? What do I want?
· How much does encryption affect the drives performance?
· Could I have some sort of automatic way that would automaticly open the drive for access once I login (through a startup script for example) without severly decreasing the security (people finding out the key by stealing my laptop for example)?
Thanks in advance