METHOD AND APPARATUS FOR CENTRALIZED ENCRYPTION KEY CALCULATION

摘要

A system and method for encrypting transmissions between a plurality of communication nodes and a mobile station (15), wherein the algorithm (32) for generating an encryption key resides within a first communications node (20). A second communications node (50) requiring encryption between the node and a mobile station (15) requests (75) and encryption key from the first communications node (20) through a PMAP interface (55) interconnecting the nodes. The first node (20) genarates (85) the encryption key and a countersign and transmits (90) them back to the second communications node (50). The transmitted countersign is compared (100) with a countersign provided by the mobile station (15), and if they match, transmissions (105) from the second communications node (50) to the mobile station (15) are encrypted using the provided key.