Algorithm 1: Federated Quondam Signature Algorithm (FQSA)

Step 1: Start

Step 2:

Collect information from the client on the Client Connection Request (CR), Client Identity (CI), and Time Stamp (TS).

Step 3:

Divide Client Identity (CI) into two parts:

- MAC ADD: Extract first eight digits of CI to obtain MAC address.

- Eight-Digit Hexadecimal: Convert MAC address to eight-digit hexadecimal value (each digit represents 4 bits).

Step 4:

Initialize federated learning parameters:

- Define global model.

- Specify number of participating devices (N).

- Set communication rounds (R).

Step 5:

For each communication round r in [1, R]:

For each participating device i in [1, N]:

- Send global model to device i.

- Device i updates local model using its own data and the received global model.

- Device i trains its local model using federated learning.

- Device i computes a local Quondam Signature (LQS) using the updated local model.

Step 6:

Aggregate Local Quondam Signatures:

- Collect all local Quondam Signatures (LQS) from participating devices.

- Compute the global Quondam Signature (GQS) by aggregating the LQS.

Step 7:

Perform Device Authentication:

- Attach GQS to the client’s connection request (CR).

- Send CR with GQS to the server for device authentication.

Step 8:

End