Authentication data exchange procedure for mobile phones uses two part encryption with different bytes of random number and algorithm output combination to give authentication word and shared key

摘要

An authentication data exchange procedure uses 3 DES (Data Encryption Standard) or MAC (Message Authentication Code) encryption algorithms (35A, 35B) with input from least and most significant bytes of a random number (RAND) and operating keys (KA, KA2-Kd) derived from two keys (Ki, Kd) to create data for exclusive OR (41) combination as authentication word (SRES) and shared encryption key (Kc) allowing the link. Includes an Independent claim for use of the least and most significant bytes from the first operating key as the respective operating keys for the encryption algorithms (35A, 35B)