Glossary
Defence in depth
Stacking several independent protections, so that a single flaw is never enough to compromise everything.
Defence in depth consists of multiplying protections (technical, organisational, human) rather than betting everything on a single barrier. If one layer gives way, the next takes over, which buys time to detect and limits the damage. It is the opposite of the "fortress" that is solid outside but empty inside.
See also
EncryptionMaking information unreadable without the right key, to protect its secrecy.Hashing (hash)Turning a piece of data into a unique, non-reversible "fingerprint", useful for checking a file or protecting a password.Trojan horse (trojan)A booby-trapped program that hides inside normal-looking software and activates once you install it.Computer worm (worm)Malicious software that spreads on its own from one machine to another, without anyone having to click.