Protectedly reading out an enciphered, cryptographic key

Method and apparatuses 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.