Abstract: Methods, apparatuses, devices and computer readable media are provided in relation to device enrolment. In one example, an electronic device is provided. The electronic device comprises a security module having a physical unclonable function (PUF). The security module is configured to establish an enrolment key pair (EPK, ESK) based on a first challenge and response to the PUF, the enrolment key pair comprising an enrolment public key (EPK) and an enrolment secret key (ESK). The electronic device is configured to establish a device key pair (DPK, DSK) based on a second challenge and response to the PUF, the device key pair comprising a device public key (DPK) and a device secret key (DSK). The electronic device further comprises one or more memories having installed thereon a primary trusted root certificate.

Abstract: Methods, apparatuses, devices and computer readable media are provided in relation to enrolment. In one example, an electronic device is provided. The electronic device comprises a security module having a physical unclonable function (PUF). The security module is configured to establish an enrolment key pair (EPK,ESK) based on a first challenge and response to the PUF, the enrolment key pair comprising an enrolment public key (EPK) and an enrolment secret key (ESK). The electronic device further comprises one or more memories. The electronic device further comprises one or more processors configured to, over a secure connection, transmit a certificate signing request (CSR) comprising a device identifier and the EPK to a server for a certificate certifying that the EPK is associated with the device identifier, wherein the CSR is signed using the ESK, and wherein the device identifier is based on a function of the EPK.

Abstract: An electrode arrangement for an array of electrically-controllable elements comprises a series of generally parallel electrodes (16) each for extending along a respective line of the electrically-controllable elements, and a series of driver lines (20(1-6)) for receiving driving signals. Each electrode is connected to a plurality of the driver lines each via a respective impedance (26). Each electrode is so connected to at least three of the driver lines. Additionally or alternatively, the driver lines are so connected to the electrodes such that the driver lines cannot be split into a pair of arbitrary groups of the driver lines for which (a) each group has generally the same number of driver lines and (b) each electrode is so connected to at least one of the driver lines in one of the groups and to at least one of the driver lines in the other of the groups. This enables the ratio of the number of electrodes to the number of driver lines to be increased.