CEH

404 Chapter 17 ■ Physical Security

Lock types include

■ Mechanical (warded and pin-and-tumbler)

■ Cipher locks (smart and programmable)

Warded locks are the simplest form of mechanical lock. The design of mechanical locks

uses a series of wards that a key must match up to in order to open the lock. Although it is

the cheapest type of mechanical lock, it is also the easiest to pick. Pin-and-tumbler locks

are considered more advanced. These locks contain more parts and are harder to pick than

warded locks. When the correct key is inserted into the cylinder of a pin-and-tumbler lock,

the pins are lifted to the right height so that the device can open or close. More advanced

and technically complex than warded or pin-and-tumbler are cipher locks, which have a

keypad of fixed or random numbers that requires a specific combination to open the lock.

Figure 17.3 shows a cipher lock.

FIGURE 17.3 One kind of cipher lock

Locks are good physical deterrents and work quite well as a delaying mechanism, but

a lock can be bypassed through lock picking. Lock-picking is not the fastest way to

bypass a lock but can be used to avoid detection. Criminals tend to pick locks because it is