slashing-protector

slashing-protector provides an HTTP API to protect Ethereum 2.0 validators from slashing.

Setting up a server

Clone this repository:

git clone github.com/bloxapp/slashing-protector

Run with Docker:

cd slashing-protector
docker-compose up

API is ready for use at http://localhost:9369 🤙

Client usage

Use the client package to interact with the slashing-protector API:

import (
    "log"
    "net/http"
    sp "github.com/bloxapp/slashing-protector/http"
)

client := sp.NewClient(&http.Client{})

// Check if an attestation is slashable:
check, err := client.CheckAttestation(ctx, network, pubKey, signingRoot, &phase0.Attestation{...})
if err != nil {
    return err
}
if check.Slashable {
    return errors.New("slashable attestation: %s", check.Reason)
}
// <- Not slashable, can submit!

// Check if a proposal is slashable:
check, err := client.CheckProposal(ctx, network, pubKey, signingRoot, &altair.BeaconBlock{...})
if err != nil {
    return err
}
if check.Slashable {
    return errors.New("slashable proposal: %s", check.Reason)
}
// <- Not slashable, can submit!

Developer guide

slashing-protector leverages Prysm's bbolt-based slashing protection. (See https://github.com/prysmaticlabs/prysm/tree/v2.0.4/validator/db/kv)

This means that when Prysm releases a version, the dependency might need to be updated. Specifically, if the release fixes a bug or implements a specification change regarding slashing protection, then the dependency must be updated.

A good practice would be to update the dependency with every Prysm stable release.

Updating the Prysm dependency

1. #️⃣ Copy the commit hash of the Prysm release or hotfix
2. 📁 Navigate to slashing-protector's directory
3. 📦 Edit go.mod and paste the first 12 characters of the commit hash in the Prysm dependency:

   replace github.com/prysmaticlabs/prysm v1.4.4 => github.com/prysmaticlabs/prysm v1.4.2-0.20211005004110-<short_hash>
   

4. 🧹 Run go mod tidy and it'll tell you that the timestamp (right before the hash) is wrong and what it should be instead. Copy the correct timestamp and update it in go.mod. Run go mod tidy again to ensure everything's okay.
5. 🧪 Run the tests to ensure no breaking changes.