// Section 5.2 · Protocol

Node Authentication

1 min5.2Protocol

// 2 of 5 · the proof model

Every message a node emits is signed.

// 5.2 · node authentication · the actor binding primitive

Unattributable returns are dropped.

Nodes register an RSA public key when they join the network. Every message the node emits afterward is signed with the corresponding private key. The coordinator verifies the signature against the registry on receipt. Anything unsigned, anything with an invalid signature, anything that does not bind to a registered node is discarded at the coordinator boundary.

The verification flow

// three checks · before the result is admitted

EXTRACT SIGNATURE

Coordinator extracts the signature header from the message envelope. Messages without a signature header drop immediately.

LOOKUP PUBKEY

Resolve node_id → registered RSA public key from the node registry. Unknown node_id drops the message.

VERIFY

rsa_verify(pubkey, message_body, signature). A failed verification drops the message and increments a fingerprinting counter against the source IP.

The signing primitive

// rsa-2048 · sha-256 hash inside · standard scheme

// node-side · python pseudocode

def sign_result(node_key: PrivateKey, request_id: bytes, result: bytes, poe: bytes) -> bytes:
    """Sign the (request_id, result, poe) tuple before returning to the coordinator."""
    message = request_id + result + poe
    return rsa_sign_pkcs1v15(node_key, sha256(message))

# Node returns:
#   { request_id, result, poe, sig }

// coordinator-side · verification

def verify_return(returned: RequestReturn) -> bool:
    pubkey = node_registry.get(returned.node_id)
    if pubkey is None:
        return False  # unknown node
    message = returned.request_id + returned.result + returned.poe
    return rsa_verify_pkcs1v15(pubkey, sha256(message), returned.sig)

// BINDS

Actor binding

Proves the specific node holding node.key produced and submitted the message. The signature is unforgeable without that key.

// DOES NOT BIND

Result correctness

Says nothing about whether the result is honest. A node can sign a fabricated result with a valid signature. Honesty is enforced by §5.5 redundancy.

// Reading path

The Proof Model · parent hub Proof of Execution · the commitment the signature wraps End-to-End Encryption · the channel binding primitive