Information processing system, information processing method, one or more non-transitory computer-readable storage media having information processing program stored therein

An information processing method of a client device, the method comprising:

• receiving challenge data transmitted from a server,
• generating response data from the challenge data based on a client response key,
• transmitting the response data to the server,
• transmitting first data that is encrypted with a server key for generating a server response key to the server, and
• receiving, from the server, a verification result based on the verification of the response data performed based on the server response key generated based on data decrypted from the encrypted data using the server key.

A client device, comprising:

• a memory and at least one processor, the memory storing instructions that, when executed causes the at least one processor to perform operations comprising:
• receiving challenge data transmitting from a server,
• generating response data from the challenge data, based on a client response key,
• transmitting the response data to the server,
• transmitting first data that is encrypted with a server key for a generating a server response to the key server, and
• receiving, from the server, a verification result based on verification of the response data performed based on the server response key generated based on the data decrypted from the first encrypted data using the server key.