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EIP-8025 -- The Beacon Chain

Note: This document is a work-in-progress for researchers and implementers.

Table of contents

Introduction

These are the beacon-chain specifications to add EIP-8025, enabling stateless validation of execution payloads through execution proofs.

Note: This specification is built upon Gloas and imports proof types from proof-engine.md.

Types

Name SSZ equivalent Description
ProofType uint8 The type identifier for the proof

Constants

Execution

Note: The execution values are not definitive.

Name Value
MAX_PROOF_SIZE 4194304 (= 4,096 KiB, 4 MiB)

Domains

Name Value
DOMAIN_EXECUTION_PROOF DomainType('0x0E000000')

Containers

New PublicInput

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class PublicInput(Container):
    new_payload_request_root: Root

New ExecutionProof

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class ExecutionProof(Container):
    proof_data: ByteList[MAX_PROOF_SIZE]
    proof_type: ProofType
    public_input: PublicInput

New SignedExecutionProof

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class SignedExecutionProof(Container):
    message: ExecutionProof
    validator_index: ValidatorIndex
    signature: BLSSignature

Beacon chain state transition function

Execution proof

Note: Proof storage is implementation-dependent, managed by the ProofEngine.

New process_execution_proof

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def process_execution_proof(
    state: BeaconState,
    signed_proof: SignedExecutionProof,
    proof_engine: ProofEngine,
) -> None:
    proof_message = signed_proof.message

    # Verify prover is an active validator
    validator = state.validators[signed_proof.validator_index]
    assert is_active_validator(validator, get_current_epoch(state))

    domain = get_domain(state, DOMAIN_EXECUTION_PROOF, compute_epoch_at_slot(state.slot))
    signing_root = compute_signing_root(proof_message, domain)
    assert bls.Verify(validator.pubkey, signing_root, signed_proof.signature)

    # Verify the execution proof
    assert proof_engine.verify_execution_proof(proof_message)