Abstract: The present invention relates to a transaction method between a secure processor and a transaction server, via a non-secure processor or a non-secure link, connected to a routing controller, the method including steps of: the controller transmitting to the secure processor, a command message sent by the non-secure processor or by the non-secure link, the controller receiving a response message sent by the secure processor, and the controller transmitting the response message to the non-secure processor or via the non-secure link, the controller analyzing the content of the response message so as to detect data of a first type therein, and removing detected data of the first type from the response message before transmitting it to the non-secure processor or via the non-secure link.

Abstract: An integrated circuit includes a communication interface circuit, a cryptographic algorithm, a countermeasure configured to protect the cryptographic algorithm against side-channel attacks, and a mask generator configured to provide the countermeasure with mask values. The integrated circuit is configured to execute a specific command requiring the disclosure of mask values used by the countermeasures to protect the cryptographic algorithm during a cryptographic session, and, in response to such a command, to send the mask values through the communication interface circuit.