Apparatus authentication system, management device, and apparatus authentication method

A management device comprising:

• a counter that counts the number of times authentication of a first communication device has been successful, the authentication being performed by another communication device;
• a generating unit that generates a password used for authentication of the first communication device based on the number of times counted by the counter;
• and
• a sending unit that sends, to a second communication device, a registration request that requests registration of the password generated by the generating unit.

An apparatus authentication method used in an apparatus authentication system including a first communication device and a second communication device that are capable of performing wireless communication with each other and including a management device that manages an operation of the first communication device, the apparatus authentication method comprising:

• generating, using a processor of the management device, a first password used for authentication of the first communication device based on a first number of times counted by a first counter that counts the first number of times authentication of the first communication device has been successful;
• sending, from the management device to the second communication device, a registration request that requests registration of the first password;
• generating, using a processor of the first communication device, a second password used for authentication of the first communication device based on a second number of times counted by a second counter that counts the second number of times authentication of the first communication device has been successful;
• sending, from the first communication device to the second communication device, a connection request that includes the second password and that requests a connection to the second communication device;
• and
• comparing, using a processor of the second communication device, the first password registered in accordance with the registration request with the second password included in the connection request and determining, using the processor of the second communication device, whether authentication of the first communication device is successful.