Methods for performing an authentication procedure and for message exchange

A method for performing an authentication procedure between a verifying device 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;
• and
• delivering the authentication response to the verifying device;
• wherein at least one of the authentication challenge or authentication response is encoded as a sequence of qubits and delivered over a quantum communication channel between the verifying device and the responding device.

A method, performed by a first device, 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
• if 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 message from a first device, 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 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 message and a second signature based on the parameter sent to the first device and on the message symbols of the message;
• verifying the second signature;
• and
• if the verification of the second signature is successful:
• comparing the estimated message from the received sequence of qubits with the received message symbols;
• and
• if a probability of error between the estimated message and the received message symbols is below a threshold value, determining that the message has been correctly received.

A verifying device for performing an authentication procedure between the verifying device and a responding device, wherein the verifying and responding devices are provisioned with security credentials, the verifying device comprising processing circuitry configured to:

• generate an authentication challenge;
• deliver the authentication challenge to the responding device;
• receive an authentication response from the responding device;
• and
• verify the authentication response;
• wherein at least one of the authentication challenge or authentication response is encoded as a sequence of qubits and delivered over a quantum communication channel between the verifying device and the responding device.

A responding device for performing an authentication procedure between a verifying device and the responding device, wherein the verifying and responding devices are provisioned with security credentials, the responding device comprising processing circuitry configured to:

• receive an authentication challenge from the verifying device;
• generate an authentication response based on the authentication challenge;
• and
• deliver the authentication response to the verifying device;
• wherein at least one of the authentication challenge or authentication response is encoded as a sequence of qubits and delivered over a quantum communication channel between the verifying device and the responding device.