Information processing device

An information processing device includes a first transmitter, one or more processors, and a recording medium. The first transmitter is configured to transmit first key-identifying information using a radio-frequency electromagnetic wave having a predetermined frequency, the first key-identifying information being linked to a predetermined vehicle. The recording medium stores a program configured to be executed by the one or more processors. The program includes one or more instructions configured to cause the one or more processors to perform a process to stop the first transmitter from transmitting the first key-identifying information when it is determined that the radio-frequency electromagnetic wave having the predetermined frequency has increased in intensity.