PROTECTEDLY READING OUT AN ENCIPHERED, CRYPTOGRAPHIC KEY

摘要

Method and apparatus for protectedly reading out an enciphered, cryptographic key (Ksec) stored in a first memory (2) of a first communication apparatus (8; 8'), comprising the following steps: a) making available a first predetermined number (PW; X) by the first communication apparatus (8; 8'); b) receiving the first predetermined number (PW; X) by the second communication apparatus; c) calculating a Message Authentication Code (MAC) by the second communication apparatus on a second predetermined number, using the first predetermined number (PW; X), and with the aid of a predetermined key (Kicc); d) making available the Message Authentication Code by the second communication apparatus (6; 13); e) deciphering the cryptographic key by the first communication apparatus (8; 8'), using the Message Authentication Code as a deciphering key.