Abstract: An electronic marking for verifying the authenticity of an object, including an antenna, an analogue transceiver circuit, a microcontroller, and at least one secure cryptoprocessor, in which the antenna is connected to the analogue transceiver circuit; the microcontroller is connected both to the analogue transceiver circuit and the at least one secure cryptoprocessor; the at least one secure cryptoprocessor is designed to securely generate a digital signature; the electronic marking has one or more electrical sensor conductors; the at least one secure cryptoprocessor is connected to at least one of the sensor conductors and designed to determine at least one electrical property of the connected at least one sensor conductor; and the one or more electrical sensor conductor(s) are distinct from the antenna and are positioned to overlap, at least partly, with said antenna.

Abstract: Set of two or more dongles for providing a digital signature, wherein each dongle holds a secret key, wherein each dongle is configured to receive a message, to compute a digital signature of the received message using the secret key, and to transmit the computed digital signature, wherein at least one of the dongles is configured to, before computing the digital signature, verify the presence of at least one other dongle belonging to the set, and to compute the digital signature only upon successful verification of the presence of one or more other dongles.

Abstract: Method for suspending a physical protection of an object by a protection device, wherein a host device receives a first and second public key, a third public key and a signed combined identifier incorporating the first and second public keys, wherein the signed identifier is signed with a third private key, which third private key is cryptographically associated with the third public key; the host device requests a search of transactions within a public transaction directory; the host device authenticates the first and second public keys using a signature of the signed identifier; the host device authenticates the protection device and sends an unlock request to the dongle if the search of the transaction directory yields at least one transaction and the first and second public keys, the protection device and the dongle are authentic; and in reaction the dongle sends an unlock command to suspend the protection of the object.