Key fob
From Wikipedia, the free encyclopedia
A key fob is a decorative item many people often carry with their keys, on a ring or a chain, to provide a better grip or to make a personal statement. Key fobs are often mistakenly called "key rings" in colloquial usage.
Fobs vary in size and style. Most common are simple shapes of smooth metal or plastic, often with a message or symbol. A fob may be strictly symbolic, or it may be functional itself. For examples, many fobs are small flashlights, compasses, calculators, penknives, store discount cards, bottle openers, or USB flash drives.
Electronic key fobs are used for remote keyless entry systems on motor vehicles. Early electric key fobs operated using infrared and required a clear line of sight to function. These could be copied using a programmable remote control. More recent models use challenge-response authentication over radio frequency, so these are harder to copy and do not need line of sight to operate.
Key fobs are increasingly used in apartment buildings and condominium buildings for access to common areas (ie. lobby doors, storage areas, fitness room, pool). They can be programmed to allow access only to those areas in which the tenant or owner is permitted to access, or only within certain time frames.
Telecommuters may also use an electronic device known as a key fob that provides one part of a three way match to log in over an unsecure network connection to a secure network. This kind of key fob may have a keypad on which the user must enter a PIN into to retrieve an access code, or it could be a display-only device such as a VPN token that algorithmically generates security codes as part of a challenge/response authentication system. The most well-known example of the latter type is RSA's SecurID token.
