From Martin Gregorie
You report that software manufacturers are moving towards the use of full-disc encryption to protect computer data (29 January, p 17). It has in fact been a standard part of the Linux operating system for at least two years. It works by encrypting information on parts of the disc using a password, which is supplied when the computer boots up.
However, this does not protect laptops that are carried around in a hibernated or stand-by state, because the password is only requested when the computer starts up. The disc remains accessible until the machine is shut down and rebooted. I imagine this would be the same for any operating system-based encryption scheme.
Harlow, Essex, UK
