Method of replacing a current key in a security element and corresponding security element

Abstract

The disclosure concerns a method of replacing a current key in a security element co-operating with a terminal in a network operated by a network operator, the method includes trying to decrypt the encrypted message by using the current key; selecting in a table stored in the secure element another key and try to decrypt the encrypted message by using the other key; replacing atomically the current key by the rescue key and do not use the current key anymore, the rescue key replacing the current key and, otherwise, try to decrypt the encrypted message by using another rescue key of the window if such another rescue key exists, until all rescue keys have been selected and used for decrypting the encrypted message and, if none of the rescue keys permit to decrypt the encrypted message, select the blocking key; and blocking the corresponding functionality of the security element.