Crypto by Steven Levy, Viking, $24.95, ISBN 0670859508
SINCE the Second World War, international communications have been hoovered
up from undersea cables and microwave links, and increasingly from computer
networks and mobile phones. Sorted and sanitised, they become the intelligence
reports intended for the eyes only of government ministers. In Britain, the
agency that performs this work is Government Communications Headquarters (GCHQ)
in Cheltenham, Gloucestershire.
It was here in 1969 that the mercurial scientist James Ellis invented “public
key” cryptography, a revolutionary code that allows secret communication without
sharing a secret key. As a direct consequence, Britain acquired a new…
