"WHY stick a phone in the freezer?" sounds like the first line
of a joke. But Tilo Müller and Michael Spreitzenbarth, from the
Friedrich-Alexander University in Germany, believe the answer is
not at all funny, as they have shown that chilling a mobile
phone's memory chip may permit mischief-makers to skim sensitive
data from it.  Messrs Müller and Spreitzenbarth have built on
research by a group at Princeton University. In 2008 Ed Felten
and his team used nothing fancier than a can of compressed air
to chill memory chip modules while a computer was running,
remove them and pilfer critical data like passwords, which are
temporarily stored in the modules' chips. Previously, it had
been thought that if this were even possible—given how rapidly
bits in a computer's "random access memory" (RAM) decay once
power is removed—it would require complex and expensive kit.
The Princeton boffins found the freezing ruse bypassed the
protections of full-disk encryption (FDE). An FDE-enabled drive
exchanges data between disk