Patent ID: 8811609

Claim:
An information protection system comprising: a mobile terminal that requests a key sequence from an encryption module by transmitting a message including a Personal Identification Number (PIN) number input by a user, and encrypts or decrypts one or more communication signals, including voice signals and data signals, based on the key sequence when the key sequence is received from the encryption module; and the encryption module that is connected to the mobile terminal, encrypts a security key using the PIN number and an identifier of the mobile terminal, decrypts the encrypted security key when requested by the mobile terminal, generates the key sequence based on the decrypted security key, transmits only the key sequence to the mobile terminal, and maintains the security key therein, wherein the encryption module determines whether to decrypt the encrypted security key by determining whether the PIN number of the message received from the mobile terminal is identical to a previously stored PIN number, and wherein, when the PIN number of the message received from the mobile terminal is not identical to the previously stored PIN number, the encryption module increases a PIN number error count, and then terminates a communication performed with the mobile terminal based on a result of comparison of the PIN number error count and an error reference value.