USIM METHOD FOR ENCRYPTING PACKET USING USIM IN INTERNET NETWORK

The present invention relates to a flexible symmetric key encryption method as an invention of applying a SIM card authentication technique in a mobile communication network to packet encryption in an internet network. The present invention is provided for a packet encryption method in an internet network by using a mobile communication USIM. An encryption/decryption method according to an embodiment of the present invention to achieve the above-mentioned purpose includes a step of providing the same encryption key for both transmission/reception ends in real time in the symmetric encryption method. According to the present invention, the symmetric key encryption method using a mobile communication SIM card authentication technology prevents problems caused by the leakage of an encryption key (same as a decryption key) which is the biggest problem of the symmetric key encryption method since the symmetric key changes every time. An application requests an IMSI to a SIM when executing the application (for example, internet browser) installed in a mobile terminal (ME) and delivers the IMSI received as a response to an internet service provision server (for example, insertion into an http header in a case of http). The internet service provision server delivers an IMSI while requesting an encryption key to a security gateway server. The security gateway server requests authentication information to the AuC of a communication company corresponding to the IMSI since the communication company can be identified by checking the IMSI. The AuC of the communication company transmits a random number (RAND) and an authentication result 1 (RES1) to the security gateway server in response to the authentication information request. 본 발명은 이동통신망에서의 SIM카드 인증 기법을 인터넷 망에서의 패킷 암호화에 적용한 발명으로써, 유동적 대칭키 암호화 방식에 대한 발명이다.