FIGURE 2-1. The Onity door lock
THE MAGNETIC STRIPE
We’ve all come across cards with magnetic stripes multiple times in our lives. From credit
cards to mass-transit tickets to hotel room keys, we’ve come to depend upon cards with mag-
netic stripes for access to services and physical places. Figure 2-2 illustrates the back side of a
typical credit card with a magnetic stripe (also known as a magstripe). The label (1) indicates
the magnetic stripe, while (2) is the signature strip and (3) represents the card security code
(CSC). Our discussion in the following sections pertains to hotel-room key cards, which typi-
cally have only the magnetic stripe on the back with the logo of the hotel on the front.
FIGURE 2-2. Card with magnetic stripe
Typically, magstripes contain three distinct tracks that can store different blocks of data.
Tracks 1 and 2 are commonly used by the financial industry to issue ATM, debit, and credit
HOTEL DOOR LOCKS AND MAGNETIC STRIPES 39