Slashing Protection Recovery

This repository contains a utility to recover Eth2 validator slashing protection information in the format defined by EIP-3076: Validator Client Interchange Format (Slashing Protection) v5. The output file can be imported into an Eth2 validator client to populate the client-specific slashing protection database, thereby restoring the slashing protection guarantees.

‼️Disclaimer: Absolutely no warranties. Use at your own risk.‼️

Overview

General Assumptions

These assumptions are made for all slashing protection rebuild methods:

• The validator is offline while running this script.
• This script is run on a machine with accurate system time.
• The validator has always been using a validator client with accurate system time.

Slashing Protection Rebuild Methods

1. uc_safe (Safe)

Description

The uc_safe method generates slashing protection information that only allows the validator to make attestations such that source.epoch >= current_epoch - 1 and target.epoch > current_epoch. As compared to the other methods, this method is unconditionally safe (hence the name uc_safe) as long as the accurate system time requirement is met. When used with --validator_pubkey or --validator-pubkey-file options, this method is usable without an Eth2 API (recommended).

A single entry will be made in each of the attestation slashing protection and block slashing protection items. The entries will be generated in the following manner:

• Attestation Slashing Protection:
  • source_epoch: current_epoch - 1
  • target_epoch: current_epoch
• Block Slashing Protection:
  • slot: current_slot

These entries prevent the validator from making attestations until the justified epoch is at least current_epoch - 1, and from proposing blocks in the current slot, because of slashing protection conditions 2, 4, and 5.

Validator Activity Implications

This may lead to some false positives from the slashing prevention detection component (i.e., messages that are not actually slashable are identified as slashable). The validator WILL lose out on rewards because of inactivity in AT LEAST the current epoch.

Further, if the Eth2 network does not produce new justified blocks, the validator will remain offline. Notably, if a large fraction (> 1/3rd) of validators are offline, a validator using a slashing protection file produced by this method will remain offline until the network recovers.

2. future_only

Specific Assumptions

• The beacon node providing the Eth2 API is fully synced.

Description

The future_only method generates slashing protection information in a way that only allows the validator to make attestations in future epochs, and blocks in future slots.

A single entry will be made in each of the attestation slashing protection and block slashing protection items. The entries will be generated in the following manner:

• Attestation Slashing Protection:
  • source_epoch: current_justified_epoch
  • target_epoch: current_epoch
• Block Slashing Protection:
  • slot: current_slot

This prevents the validator from making attestations in the current epoch, and blocks in the current slot, because of slashing protection conditions 2, 4, and 5.

Validator Activity Implications

This may lead to some false positives from the slashing prevention detection component (i.e., messages that are not actually slashable are identified as slashable). The validator WILL lose out on rewards because of inactivity in the current epoch.

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Install

• Prerequisites:
  • Python 3
  • (Optional) A fully synced Eth2 Beacon Node with an accessible Eth2 API endpoint
• Installation:
  1. Verify that the installation will use the correct Eth2.0 spec version by checking the commit hash in ETH2_SPEC_COMMIT in ./Makefile.
  2. Use make install to install the dependencies in a venv.
  3. Activate the venv before executing the utility using . venv/bin/activate

Usage

usage: rebuild_slashing_protection.py [-h] (--eth2-api ETH2_API | --genesis-info GENESIS_INFO) --method
                                      {uc_safe,future_only}
                                      (--validator-pubkey VALIDATOR_PUBKEY [VALIDATOR_PUBKEY ...] | --validator-pubkey-file VALIDATOR_PUBKEY_FILE)
                                      [--output-file OUTPUT_FILE] [--log-level {debug,info,warn}]

Utility to rebuild Eth2 validator slashing protection information

optional arguments:
  -h, --help            show this help message and exit
  --eth2-api ETH2_API   Eth2 API to fetch Beacon Chain information from
  --genesis-info GENESIS_INFO
                        file containing genesis information to use in the absence of an Eth2 API
  --method {uc_safe,future_only}
                        method used to rebuild the slashing protection information
  --validator-pubkey VALIDATOR_PUBKEY [VALIDATOR_PUBKEY ...]
                        pubkey(s) of validator(s) for which to regenerate slashing protection information
  --validator-pubkey-file VALIDATOR_PUBKEY_FILE
                        file containing whitespace-separated pubkey(s) of validator(s) for which to regenerate slashing
                        protection information
  --output-file OUTPUT_FILE
                        output file for slashing protection information (default: "protection-file.json")
  --log-level {debug,info,warn}
                        preferred log level

Recommended Usage

The --method uc_safe along with genesis information from genesis.json is highly recommended. These step-by-step instructions outline the recommended usage:

0. Download this repository using git clone https://github.com/adiasg/eth2-slashing-protection-rebuild.git.

1. Installation: verify that the installation will use the correct Eth2.0 spec version by checking the commit hash in ETH2_SPEC_COMMIT in ./Makefile. Then run make install, followed by . venv/bin/activate.

2. Fill in your validator public key(s) in a ./pubkey.txt file.

   ./pubkey.txt:

   0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
   0x100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
   

3. Verify that genesis.json contains the correct "genesis_time" and "genesis_validators_root" for the Eth2.0 mainnet. These values can be checked against your beacon node's HTTP API at the /eth/v1/beacon/genesis endpoint or some other trusted source.

   ./genesis.json:

   {
     "genesis_time": "1606824023",
     "genesis_validators_root": "0x4b363db94e286120d76eb905340fdd4e54bfe9f06bf33ff6cf5ad27f511bfe95"
   }
   

4. Run the utility using the recommended options. Remember to activate the venv using . venv/bin/activate before this.

   python rebuild_slashing_protection.py --genesis-info ./genesis.json --method uc_safe --validator-pubkey-file ./pubkeys.txt

   This should produce an output file protection-file.json.

   ./protection-file.json:

   {
     "metadata": {
       "interchange_format_version": "5",
       "genesis_validators_root": "0x4b363db94e286120d76eb905340fdd4e54bfe9f06bf33ff6cf5ad27f511bfe95"
     },
     "data": [
       {
         "pubkey": "0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
         "signed_blocks": [
           {
             "slot": "19094"
           }
         ],
         "signed_attestations": [
           {
             "source_epoch": "595",
             "target_epoch": "596"
           }
         ]
       },
       {
         "pubkey": "0x100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
         "signed_blocks": [
           {
             "slot": "19094"
           }
         ],
         "signed_attestations": [
           {
             "source_epoch": "595",
             "target_epoch": "596"
           }
         ]
       }
     ]
   }