# EIP-7251 -- Honest Validator

## Table of contents

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- [Introduction](#introduction)
- [Prerequisites](#prerequisites)
- [Beacon chain responsibilities](#beacon-chain-responsibilities)
  - [Block and sidecar proposal](#block-and-sidecar-proposal)
    - [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
      - [ExecutionPayload](#executionpayload)

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## Introduction

This document represents the changes to be made in the code of an "honest validator".

## Prerequisites

This document is an extension of the [Deneb -- Honest Validator](../deneb/validator.md) guide.
All behaviors and definitions defined in this document, and documents it extends, carry over unless explicitly noted or overridden.

All terminology, constants, functions, and protocol mechanics defined in the updated [Beacon Chain doc of EIP-7251](./beacon-chain.md) are requisite for this document and used throughout.
Please see related Beacon Chain doc before continuing and use them as a reference throughout.

## Beacon chain responsibilities

All validator responsibilities remain unchanged other than those noted below.

### Block and sidecar proposal

#### Constructing the `BeaconBlockBody`

##### ExecutionPayload

`prepare_execution_payload` is updated from the Deneb specs.

*Note*: In this section, `state` is the state of the slot for the block proposal _without_ the block yet applied.
That is, `state` is the `previous_state` processed through any empty slots up to the assigned slot using `process_slots(previous_state, slot)`.

*Note*: The only change to `prepare_execution_payload` is the new definition of `get_expected_withdrawals`.

```python
def prepare_execution_payload(state: BeaconState,
                              safe_block_hash: Hash32,
                              finalized_block_hash: Hash32,
                              suggested_fee_recipient: ExecutionAddress,
                              execution_engine: ExecutionEngine) -> Optional[PayloadId]:
    # Verify consistency of the parent hash with respect to the previous execution payload header
    parent_hash = state.latest_execution_payload_header.block_hash

    # Set the forkchoice head and initiate the payload build process
    withdrawals, _ = get_expected_withdrawals(state)  # [Modified in EIP-7251]

    payload_attributes = PayloadAttributes(
        timestamp=compute_timestamp_at_slot(state, state.slot),
        prev_randao=get_randao_mix(state, get_current_epoch(state)),
        suggested_fee_recipient=suggested_fee_recipient,
        withdrawals=withdrawals,
        parent_beacon_block_root=hash_tree_root(state.latest_block_header),
    )
    return execution_engine.notify_forkchoice_updated(
        head_block_hash=parent_hash,
        safe_block_hash=safe_block_hash,
        finalized_block_hash=finalized_block_hash,
        payload_attributes=payload_attributes,
    )
```