To provide a receiver and a transmitter that reduce damage to the receiver while securely unlocking a door.

A contactless authentication system 1 is equipped with a reader 3 and a key 5. A bowl-shaped recess 29 is formed in the center of a showing part 28 formed on the front 11b of the reader 3 and it's inner peripheral surface is a black reception surface. In the recess 29, a circular through-hole 31 indicating the center of the recess 29 is formed around the center. Further, an arrow-shaped index is formed in the center of the grip 43 of the key 5 while directed to the base end 5a of the key 5. A user grips the key 5 on the side of an insert part 45 and puts the key closer up to a distance of about 2 centimeters from the showing part 28 of the reader 3. When a receiver 25 authenticates unique identification information that a transmitter sends, an LED that the reader 3 is equipped with blinks.

COPYRIGHT: (C)2007,JPO&INPIT