公开(公告)号：WO2022189133A1

公开(公告)日：2022-09-15

申请号：PCT/EP2022/054330

申请日：2022-02-22

Applicant: THALES DIS FRANCE SAS

Inventor： OHANIAN, Henri ,  JOUBERT, Nicolas ,  BARRAS, Cyril ,  BOUZAYANE, Oussama

IPC: H04W12/03 ,  H04W12/047 ,  H04W12/069 ,  H04W12/30

Abstract: The invention concerns a method of replacing a current key (KEY_1) in a security element co- operating with a terminal in a network operated by a network operator, the method comprising: A – When receiving an encrypted message from a distant platform, trying to decrypt the encrypted message by using the current key (KEY_1); B – If the current key (KEY_1) is not the key used by the distant platform to encrypt the message, selecting in a table stored in the secure element another key and try to decrypt the encrypted message by using the other key, the other key being: - a key called rescue key (RESCUE_KEYS) and being part of a window (30) of the table, the window (30) comprising n rescue keys, with n being >=0, or - a key called blocking key (31) if n=0 or if the blocking key has a higher priority than the rescue keys (RESCUE_KEYS), the blocking key (31) being stored outside the window (30), C – If n>0 and the rescue key permits to decrypt the encrypted message, replacing atomically the current key (KEY_1) by the rescue key and do not use the current key (KEY_1) anymore, the rescue key replacing the current key (KEY_1) and, otherwise, try to decrypt the encrypted message by using another rescue key of the window (30) 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 (31), D – If the blocking key (31) permits to decrypt the encrypted message, block the corresponding functionality of the security element.