Two layers will take longer than one, even if the first layer is easily breakable. <BR><BR>For normal use, though, (what you or I would do) using 64 bit encryption should be sufficent. If someone is ...

This is mitigated by using larger key sizes. For instance, Grover's algorithm would reduce AES-128 (128-bit key) to an effective 64-bit strength, which is a problem, but AES-256 (256-bit key) would be ...