eth2.0-specs/specs/electra/validator.md

# Electra -- Honest Validator

## Table of contents

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- [Introduction](#introduction)
- [Prerequisites](#prerequisites)
- [Block proposal](#block-proposal)
  - [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
    - [Attester slashings](#attester-slashings)
    - [Attestations](#attestations)
    - [Deposits](#deposits)
- [Attesting](#attesting)
  - [Construct attestation](#construct-attestation)
- [Attestation aggregation](#attestation-aggregation)
  - [Construct aggregate](#construct-aggregate)

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## Introduction

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

## 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 [Electra](./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.

## Block proposal

### Constructing the `BeaconBlockBody`

#### Attester slashings

Changed the max attestations size to `MAX_ATTESTER_SLASHINGS_ELECTRA`.

#### Attestations

The network attestation aggregates contain only the assigned committee attestations.
Attestation aggregates received by the block proposer from the committee aggregators with disjoint `committee_bits` sets and equal `AttestationData` SHOULD be consolidated into a single `Attestation` object.
The proposer should run the following function to construct an on chain final aggregate form a list of network aggregates with equal `AttestationData`:

```python
def compute_on_chain_aggregate(network_aggregates: Sequence[Attestation]) -> Attestation:
    aggregates = sorted(network_aggregates, key=lambda a: get_committee_indices(a.committee_bits)[0])

    data = aggregates[0].data
    aggregation_bits = Bitlist[MAX_VALIDATORS_PER_COMMITTEE * MAX_COMMITTEES_PER_SLOT]()
    for a in aggregates:
        for b in a.aggregation_bits:
            aggregation_bits.append(b)

    signature = bls.Aggregate([a.signature for a in aggregates])

    committee_indices = [get_committee_indices(a.committee_bits)[0] for a in aggregates]
    committee_flags = [(index in committee_indices) for index in range(0, MAX_COMMITTEES_PER_SLOT)]
    committee_bits = Bitvector[MAX_COMMITTEES_PER_SLOT](committee_flags)

    return Attestation(aggregation_bits, data, committee_bits, signature)
```

#### Deposits

*[New in Electra:EIP6110]* The expected number of deposits MUST be changed from `min(MAX_DEPOSITS, eth1_data.deposit_count - state.eth1_deposit_index)` to the result of the following function:

```python
def get_eth1_pending_deposit_count(state: BeaconState) -> uint64:
    eth1_deposit_index_limit = min(state.eth1_data.deposit_count, state.deposit_receipts_start_index)
    if state.eth1_deposit_index < eth1_deposit_index_limit:
        return min(MAX_DEPOSITS, eth1_deposit_index_limit - state.eth1_deposit_index)
    else:
        return uint64(0)
```

## Attesting

### Construct attestation

- Set `attestation_data.index = 0`.
- Let `attestation.aggregation_bits` be a `Bitlist[MAX_VALIDATORS_PER_COMMITTEE * MAX_COMMITTEES_PER_SLOT]` of length `len(committee)`, where the bit of the index of the validator in the `committee` is set to `0b1`.
- Let `attestation.committee_bits` be a `Bitvector[MAX_COMMITTEES_PER_SLOT]`, where the bit at the index associated with the validator's committee is set to `0b1`.

*Note*: Calling `get_attesting_indices(state, attestation)` should return a list of length equal to 1, containing `validator_index`.

## Attestation aggregation

### Construct aggregate

- Set `attestation_data.index = 0`.
- Let `aggregation_bits` be a `Bitlist[MAX_VALIDATORS_PER_COMMITTEE * MAX_COMMITTEES_PER_SLOT]` of length `len(committee)`, where each bit set from each individual attestation is set to `0b1`.
- Set `attestation.committee_bits = committee_bits`, where `committee_bits` has the same value as in each individual attestation.