Authentication response verification using qubits and quantum channel

A method for performing an authentication procedure between a verifying device located at a certain location and a responding device, wherein the verifying and responding devices are provisioned with security credentials, the method, performed by the responding device, comprising:

• receiving an authentication challenge from the verifying device;
• generating an authentication response based on the authentication challenge;
• encoding the authentication response as a sequence of qubits;
• and
• delivering the encoded authentication response to the verifying device, wherein
• the encoded authentication response is delivered over a quantum communication channel between the verifying device and the responding device,
• encoding the authentication response as the sequence of qubits comprises:
• encoding the authentication response as a sequence of photon polarisation states or coherent states of light,
• delivering the encoded authentication response over the quantum communication channel to the verifying device comprises transmitting the qubits on which the authentication response is encoded to the verifying device, and
• the method further comprises:
• receiving a parameter and a first signature, which is based on the parameter, from the verifying device;
• verifying the first signature;
• and
• if the verification of the first signature is successful:
• generating a second signature based on the received parameter and on message symbols of the authentication response;
• and
• sending the authentication response message symbols and the second signature to the verifying device.

A method, performed by a first device located at a certain location, for delivering a message to a second device, wherein the first and second devices are provisioned with security credentials, the method comprising:

• encoding the message as a sequence of qubits;
• delivering the encoded message over a quantum communication channel to the second device;
• receiving a parameter and a first signature, which is based on the parameter, from the second device;
• verifying the first signature;
• and
• based on determining that the verification of the first signature is successful:
• generating a second signature based on the received parameter and on message symbols of the message;
• and
• sending the message symbols and the second signature to the second device.

A method for receiving a first message from a first device located at a certain location, wherein the method is performed by a second device, and wherein the first and second devices are provisioned with security credentials, the method comprising:

• receiving an encoded message from the first device, wherein the encoded message comprises a sequence of qubits and is received over a quantum communication channel to the first device;
• estimating the first message from the received sequence of qubits;
• generating a first signature based on a parameter;
• sending the first signature and the parameter to the first device;
• receiving from the first device, message symbols of the first message and a second signature based on the parameter sent to the first device and on the message symbols of the first message;
• verifying the second signature;
• and
• based on determining that the verification of the second signature is successful:
• comparing the estimated message from the received sequence of qubits with the received message symbols;
• and
• based on determining that a probability of error between the estimated message and the received message symbols is below a threshold value, determining that the first message has been correctly received.

A verifying device comprising processing circuitry configured to cause the verifying device to perform a method for performing an authentication procedure between the verifying device located at a certain location and a responding device, wherein the verifying and responding devices are provisioned with security credentials, the method comprising:

• generating an authentication challenge;
• delivering the authentication challenge to the responding device, wherein delivering the authentication challenge to the responding device comprises:
• receiving a parameter and a first signature, which is based on the parameter, from the responding device;
• verifying the first signature;
• and
• based on determining that the verification of the first signature is successful:
• generating a second signature based on the received parameter and on message symbols of the authentication challenge;
• and
• sending the authentication challenge message symbols and the second signature to the responding device;
• receiving an authentication response from the responding device;
• and
• verifying the authentication response, wherein
• the authentication challenge is encoded as a sequence of qubits and delivered over a quantum communication channel between the verifying device and the responding device, and
• the encoding of the authentication challenge as the sequence of qubits comprises:
• encoding the authentication challenge as a sequence of photon polarisation states or coherent states of light, or
• encoding the authentication challenge as a sequence of entangled states of photon pairs.

A responding device for performing an authentication procedure between a verifying device and the responding device, wherein the verifying device is located at a certain location, and further wherein the verifying and responding devices are provisioned with security credentials, the responding device comprising processing circuitry configured to cause the responding device to perform a method comprising:

• receiving an authentication challenge from the verifying device;
• generating an authentication response based on the authentication challenge;
• encoding the authentication response as a sequence of qubits;
• and
• delivering the encoded authentication response to the verifying device, wherein
• the encoded authentication response is delivered over a quantum communication channel between the verifying device and the responding device,
• encoding the authentication response as the sequence of qubits comprises encoding the authentication response as a sequence of photon polarisation states or coherent states of light,
• delivering the encoded authentication response over the quantum communication channel to the verifying device comprises transmitting the qubits on which the authentication response is encoded to the verifying device, and
• the method further comprises:
• receiving a parameter and a first signature, which is based on the parameter, from the verifying device;
• verifying the first signature;
• and
• if the verification of the first signature is successful:
• generating a second signature based on the received parameter and on message symbols of the authentication response;
• and
• sending the authentication response message symbols and the second signature to the verifying device.