Several old external hard drives lying around.
What is the easiest and most robust way to encrypt them? They all have standard USB ports.
Thinking of your basic bad-guy encryption where the value of my data to anyone would outweigh the cost of having to do advanced cryptography. Where whoever found the drives would think, "This is more valuable to me formatted and resold than taking the time to figure out how to get past the encryption here."
What looks good, and strong - but won't take up too much time on my end?