Patent ID: 8364961

Claim:
An appliance authentication system comprising: a power management apparatus including a public key acquisition unit that acquires, from a manufacturer server managed by a manufacturer of an electronic appliance which is a target of an authentication process, a public key paired with a secret key that the electronic appliance and the manufacturer server hold, a ciphertext generating unit that generates a ciphertext by generating a random number and encrypting the random number by the public key acquired by the public key acquisition unit, and a ciphertext transmitting unit that transmits the ciphertext generated by the ciphertext generating unit to the electronic appliance and the manufacturer server; the electronic appliance including a first decryption unit that restores the random number by decrypting the ciphertext transmitted by the ciphertext transmitting unit, a current measuring unit that causes an electrical part to operate, based on the random number restored by the first decryption unit, and measures a value of current flowing through the electrical part, and a first transmitting unit that transmits the value of current measured by the current measuring unit to the manufacturer server; and the manufacturer server including a second decryption unit that restores the random number by decrypting the ciphertext transmitted by the ciphertext transmitting unit, a current simulator that calculates the value of current to flow through the electrical part by simulating operation of the electrical part based on the random number restored by the second decryption unit, a current value comparing unit that compares a first value of current transmitted by the first transmitting unit and a second value of current calculated by the current simulator, and a result transmitting unit that transmits a comparison result by the current value comparing unit to the power management apparatus.