If you need to protect your data at all costs, Macway (a reseller based in France) has started to market external Storeva disks that require an authentication from an infra-red key.
If one does not 'open' the disk using the IR key after having connected it, the data, via the USB controller will be inaccessible and of course illegible.
These USB cases only will be available in 2,5" from 160 GB (89TTC) and in 3,5" up to 1,5 TB (249TTC).
They are provided with two IR keys. However security does have its disadvantages, the loss of these two keys leaves the data encoded in 128 bits.
Note to finish: it is the IR key that contains the encryption code. In the event of breakdown of the electronics it will be necessary to change the case for another identical one and then one can retrieve the data intact.
To get more information:
