The chink in most computers' armour is the password. All but three sites the auditors examined used passwords to control access to computers. Most were useless. When people choose their passwords, they often pick names of spouses or pets. These are easy for colleagues to guess.
Passwords are particularly vulnerable when they remain unchanged for a long time.
The chairman of one major company the auditors investigated had kept the same password for five years. Another danger point is in computers that allow unlimited guesses at passwords. The really secure passwords are the dual-key encrypted type. These are codes distributed in two parts, which link up inside a computer. But only two or three computers, all government installations, carry such protection in Britain.