Network entities, methods, apparatuses and communications networks for authenticating an event

A first network entity for authenticating an event in a communications network the first network entity comprising a processing circuitry being configured to

• receive an event signal, wherein the event signal comprises a signal that indicates whether to activate a circuit of the first network entity,
• authenticate the event responsive to determining that the received event signal correlates with an output signal of a closed-loop shift register in the first network entity,
• perform the event in response to the event being authenticated;
• and
• trigger a change in the closed-loop shift register in order to obtain a subsequent output signal from the closed-loop shift register;
• wherein the received event signal correlates with the output signal of the closed-loop shift register responsive to a determination that the received event signal causes a determined output signal when the received event signal is fed into an open-loop shift register that uses the output signal of the closed-loop shift register as its primitive polynomial;
• and
• wherein a single shift register is used in a time-multiplexed manner to alternately provide a functionality of the closed-loop shift register and a functionality of the open-loop shift register.

A method performed by a second network entity for authenticating an event in at least one first network entity in a communications network, the method comprising

• generating an event signal to be used in authenticating the event in the at least one first network entity using output of at least one closed-loop shift register, wherein the event signal comprises a signal that indicates whether to activate a circuit of the at least one first network entity, wherein the event signal is generated in response to determining that the event is to be performed by the at least one first network entity;
• transmitting the generated event signal to the at least one first network entity;
• and
• triggering a change in the at least one closed-loop shift register in order to obtain a subsequent output signal from the at least one closed-loop shift register;
• wherein the event signal correlates with an output signal of the at least one closed-loop shift register responsive to the event signal being determined to cause an output signal when the event signal is fed into an open-loop shift register that uses the output signal of the at least one closed-loop shift register as its primitive polynomial;
• and
• wherein a single shift register is used in a time-multiplexed manner to alternately provide a functionality of the at least one closed-loop shift register and a functionality of the open-loop shift register.

A second network entity for authenticating an event in at least one first network entity in a communications network, the second network entity comprising a processing circuitry being configured to

• generate an event signal to be used in authenticating the event in the at least one first network entity using output of at least one closed-loop shift register, wherein the event signal comprises a signal that indicates whether to activate a circuit of the at least one first network entity, wherein the event signal is generated in response to a determination that the event is to be performed by the at least one first network entity,
• transmit the generated event signal to the at least one first network entity, and
• trigger a change in the at least one closed-loop shift register in order to obtain a subsequent output signal from the at least one closed-loop shift register;
• wherein the event signal correlates with an output signal of the at least one closed-loop shift register responsive to the event signal being determined to cause an output signal when the event signal is fed into an open-loop shift register that uses the output signal of the at least one closed-loop shift register as its primitive polynomial;
• and
• wherein a single shift register is used in a time-multiplexed manner to alternately provide a functionality of the at least one closed-loop shift register and a functionality of the open-loop shift register.