Patent ID: 8201222

Claim:
An authentication system for repeatedly performing an authentication process, each time a predetermined period of effective authentication elapses, comprising: a communication terminal for being connectable to a network when an authentication thereof is successful, changing between an operational state and an aborted state, and indicating a transition to said aborted state when the communication terminal changes from said operational state to said aborted state; and an authentication device for repeatedly performing the authentication process, counting said predetermined period for the communication terminal when the authentication thereof is successful, and performing the authentication process again for the communication terminal if said predetermined period elapses, wherein when the transition to said aborted state is indicated by said communication terminal, said authentication device stops counting a remaining part of said predetermined period corresponding to a remaining authentication effective period for the communication terminal, and keeps the authentication of the communication terminal in a previous authentication cycle effective; wherein said aborted state is a state in which said communication terminal connects to said network and remains capable of receiving a packet although said communication terminal stops various information processing processes as desired by a user; said communication terminal changes to said operational state and sends an authentication request to said authentication device if there is an instruction from another device through said network while said communication terminal is in said aborted state, said authentication device recognizes that said communication terminal changes to said operational state when there is an authentication request from said communication terminal and resumes counting said predetermined period.