Patent ID: 8234492

Claim:
A method for reservation access to a management server, comprising: using a one-time password of a sensor application system, which is generated by a client automatically without any intervention of a system manager transmitting a generated personal identification number (PIN) to the management server when a reservation time comes; generating, at the management server, a random number encrypted using the PIN, and transmitting the random number to the client; receiving the random number encrypted using the PIN, encrypting the received random number by a symmetric-key algorithm using a client secret key, and transmitting a random number encrypted using the client secret key to the management server; receiving, at the management server, the random number encrypted using the client secret key, and decrypting the received random number using a server secret key and the PIN; comparing a random number before the encryption using the PIN with a decrypted random number, and accepting access of the client if the two numbers are identical; and updating sensory data values used by the sensor application system periodically, wherein the client secret key and the server secret key are different keys one of which is used for decryption if the other one is used for encryption.