AUTHENTICATION AND UPDATE OF SESSION KEY GENERATION BETWEEN SERVICE NETWORK NODE AND AT LEAST ONE COMMUNICATION TERMINAL DEVICE WITH IDENTIFICATION CARD Russian patent published in 2009 - IPC H04L29/06 

FIELD: physics; communications.

SUBSTANCE: present invention relates to data encryption. At least one access key (BAK-I), sent from the service network node (DN) and at least one dispatched sequence value (SEQ) are stored on the identification card (UICC) of the communication terminal device (MS). The authenticity value (MAC-I) is calculated in the service network node and together with service data and the next sequence value (nSEQ) is sent to the MS. When data are received, the received MAC-I is compared with the calculated authenticity value (SD-MAC-I), calculated on UICC. On the UICC, nSEQ is then compared with SEQ already stored on the UICC, and only if there is a positive result of comparing both authenticity values (MAC-I/SD-MAC-I) and both sequence values (SEQ/nSEQ), the session key generated for the UICC for decrypting service data is sent to the MS.

EFFECT: more efficient protection of session keys.

12 cl, 5 dwg