Method and system for encrypting data in a wireless communication system

A method for encrypting data by a first node in a wireless communication system, the method comprising:

• performing an authentication operation with a second node, by the first node, using a first encryption key generated using a plurality of encryption key parameters, the plurality of encryption key parameters including an authentication key, first encryption key adjustment value determined based on the authentication key, and at least one of a counter value, a security association identity (SAID), and an encryption key length value;
• changing, by the first node, the first encryption key adjustment value to generate a second encryption key being identical to the first encryption key, if the authentication key is changed during a re-authentication operation performed between the first node and the second node;
• generating, by the first node, the second encryption key using the changed authentication key, a second encryption key adjustment value as the changed first encryption key adjustment value, and at least one of the counter value, the SAID, and the encryption key length value;
• and
• encrypting, by the first node, data to be transmitted to the second node using the second encryption key.

A first node for encrypting data in a wireless communication system, the first node comprising:

• a transmitter;
• a receiver;
• and
• a controller for performing an authentication operation with a second node using a first encryption key generated using a plurality of encryption key parameters, the plurality of encryption key parameters including an authentication key, a first random number, and at least one of a counter value, a security association identity (SAID), a first node IDentifier (ID), and a second node ID, changing the first random number to generate a second encryption key being identical to the first encryption key, if the authentication key is changed during a re-authentication operation performed with the second node, generating the second encryption key using the changed authentication key, a second random number as the changed first random, and at least one of the counter value, the SAID, the first node ID and a second node ID, and encrypting data to be transmitted to the second node through the transmitter using the second encryption key.

A first node for encrypting data in a wireless communication system, the first node comprising:

• a transmitter;
• a receiver;
• and
• a controller for performing an authentication operation with a second node, by the first node, using a first encryption key generated using a plurality of encryption key parameters, the plurality of encryption key parameters including an authentication key, first encryption key adjustment value determined based on the authentication key, and at least one of a counter value, a security association identity (SAID), and an encryption key length value, changing, by the first node, the first encryption key adjustment value among the plurality of encryption key parameters to generate a second encryption key being identical to the first encryption key, if the authentication key among the plurality of encryption key parameters is changed during re-authentication between the first node and the second node, generating, by the first node, the second encryption key using the changed authentication key, a second encryption key adjustment value as the changed encryption key adjustment value, and at least one of the counter value, the SAID, and the encryption key length value, and encrypting, by the first node, data to be transmitted to the second node through the transmitter using the second encryption key.