Implementing your own Proof Of Authentication. (Part 1)

In the world of IoT, companies and innovators often turn to blockchain solutions to securely automate tasks such as collecting, filtering, and identifying incoming data. While decentralized networks can be quite helpful in many respects, certain bottlenecks still hinder scalability. For example, some consensus mechanisms require extensive re-validation and computational effort, increasing both the time and energy consumed by the network. This heightened resource usage is particularly undesirable for factories and other industries that aim to reduce their environmental impact, making the exploration of more efficient blockchain protocols essential.

Thus comes the new consensus algorithm called Proof Of Authentication that will replace the existing one Proof of Work and introduce authentication in such environments to make the blockchain application-specific.

The algorithm is designed to ensure secure and authenticated block validation in a blockchain network. Each node in the network begins by combining transactions into a block, which is then signed using the node's private key. This signed block is broadcasted across the network. Trusted nodes verify the block's signature using the source node's public key to confirm its authenticity. If the block is authenticated, it is appended with a cryptographic Proof of Authentication (PoAh), ensuring integrity and traceability, and then added to the blockchain. Blocks that fail authentication are discarded, maintaining the network's reliability and security. PoAh emphasizes a lightweight yet robust validation process, making it ideal for systems prioritizing transparency, trust, and resource efficiency.

To simplify how the algorithm works, let us translate the theoretical concept into a practical Python example. The code below demonstrates the full process, from creating a block of transactions to signing, verifying, and appending it to the blockchain. By following this example, you can gain a clear understanding of the algorithm's steps and their implementation:

import hashlib
import rsa

def sha256_hash(data):
    return hashlib.sha256(data.encode()).hexdigest()

# Generate keys for demonstration
(pubkey, privkey) = rsa.newkeys(512)

# PoAh Procedure
def poah_procedure(transactions):
    # Step 1: Combine transactions to form a block
    block = "|".join(transactions)

    # Step 2: Sign the block with private key
    signed_block = rsa.sign(block.encode(), privkey, 'SHA-256')

    # Step 3: Broadcast (simulation)
    print("Broadcasting signed block...")

    # Step 4: Trusted node verifies signature
    try:
        rsa.verify(block.encode(), signed_block, pubkey)
        print("Block authenticated!")

        # Step 5: Append PoAh and add to blockchain
        poah = sha256_hash("Proof of Authentication")
        blockchain.append(f"{block} || {poah}")
        print("Block added to blockchain.")
    except rsa.VerificationError:
        print("Block verification failed. Dropping block.")

# Blockchain simulation
blockchain = []

# Example usage
transactions = ["Tx1: A->B", "Tx2: C->D"]
poah_procedure(transactions)

print("\nBlockchain:", blockchain)