NutBerry - Offroading Ethereum Transactions

A NutBerry a day keeps the sunshine your way.

The goal of the NutBerry project is a permissionless optimistic rollup layer-2 solution with support for stateful smart contracts. NutBerry intentionally has the same transaction encoding and signing scheme as Ethereum transactions to be one-to-one compatible with the existing ecosystem.

• No special/additional tooling for developers necessary.
• No special interfaces in smart contracts.

Interacting with ERC20/ERC721 tokens works exactly as on the ethereum root-chain.

In a nutshell, NutBerry improves the latency of trustless interactions(smart contracts) and improves transaction throughput.

The most anticipated feature is the possibility for on-chain EVM verification, that makes it possible to run smart contracts on a permissionless / trustless layer 2 solution. Though, the runtime has some restrictions like not be able to call other contracts. That is; a state-minimized EVM or LEVM - Lean Ethereum Virtual Machine.

Data availability is fully achieved on the root-chain and the contract is able verify and replay all transactions either through directly finalizing a Block of transactions on-chain or via non-interactive fraud proofs to enforce correctness on-chain for any given block.

Rough Roadmap

Non-exhaustive list. NutBerry is WIP

• Support the ERC20 token standard.
• Support arbitrary stateless smart contracts.
• Support the ERC721 standard.
• Stateful smart contracts, aka smart contracts with support for storage.
• Additional Signing scheme: EIP-712.
• Additional Signing scheme: BLS aggregates.
• State-roots / merkelized state.
• NutBerry-node: P2P Connectivity/Exchange via JSON RPC - Simple HTTP (pub-key, node-id) exchange with switch to https.
• Recursive Gated Computing.
• evaluation/query-interface, root-chain contracts can query the Bridge for Layer-2 contract-state.

How to get started

To install the dependencies:

yarn

This project uses geth to run the integration tests. Make sure that you have at least geth v1.9.9 available in your environment. You can run the tests with yarn test.

Deployment

Bridge

scripts/deploy.js - is a little deployment helper script.

You can run it like this:

GAS_GWEI=3 ROOT_RPC_URL=http://localhost:8222 PRIV_KEY=0x2bdd21761a483f71054e14f5b827213567971c676928d9a1808cbfa4b7501200 ./scripts/deploy.js

This script also supports passing MNEMONIC instead of a private key. In addition, you can leave both PRIV_KEY and MNEMONIC if ROOT_RPC_URL allows signing.

Client

The nutberry-node supports the following environment variables:

• Option: BRIDGE_ADDRESS
  • Type: String
  • Required: true
  • The contract address of the Bridge on the root-chain.
• Option: PRIV_KEY
  • Type: String
  • Default:
  • The private key for a root-chain account. That account should have some ether to be useful. Required to participate in the network.
• Option: PORT
  • Type: Number
  • Required: true
  • The port to listen on for the JSON-RPC interface.
• Option: HOST
  • Type: String
  • Default: localhost
  • The address to listen on for the JSON-RPC interface.
• Option: ROOT_RPC_URL
  • Type: String
  • Required: true
  • The URL for the root-chain JSON-RPC provider.
• Option: EVENT_CHECK_MS
  • Type: Number
  • Default: 15000
  • Time in milliseconds to check for Bridge event updates.
• Option: DEBUG_MODE
  • Type: Number
  • Default: 0
  • Debug mode, for development purposes.
• Option: BAD_NODE_MODE
  • Type: Number
  • Default: 0
  • For development purposes, simulates a rogue node.

Documentation

• The System Description Document.
• FAQ.

Additionaly, taking a look at contracts/Bridge.sol and tests/Bridge.js will give you an idea how things fit together.

Public Testnet

See here.

Communication

Join the Gitter chat to ask questions, harvest NutBerries and to hang out.