ethereum

README

Quorum

Quorum is an Ethereum-based distributed ledger protocol with transaction/contract privacy and new consensus mechanisms.

Quorum is a fork of go-ethereum and is updated in line with go-ethereum releases.

Key enhancements over go-ethereum:

• Privacy - Quorum supports private transactions and private contracts through public/private state separation and utilising Constellation, a peer-to-peer encrypted message exchange for directed transfer of private data to network participants
• Alternative Consensus Mechanisms - with no need for POW/POS in a permissioned network, Quorum instead offers multiple consensus mechanisms that are more appropriate for consortium chains:
  • QuorumChain - a new smart-contract based, majority voting consensus model
  • Raft-based Consensus - a consensus model for faster blocktimes, transaction finality, and on-demand block creation
• Peer Permissioning - node/peer permissioning using smart contracts, ensuring only known parties can join the network
• Higher Perfomance - Quorum offers significantly higher performance than public geth

Architecture

The above diagram is a high-level overview of the privacy architecture used by Quorum. For more in-depth discussion of the components, refer to the wiki pages.

Quickstart

The quickest way to get started with Quorum is using VirtualBox and Vagrant:

git clone https://github.com/jpmorganchase/quorum-examples
cd quorum-examples
vagrant up
# (should take 5 or so minutes)
vagrant ssh

Now that you have a fully-functioning Quorum environment set up, let's run the 7-node cluster example. This will spin up several nodes with a mix of voters, block makers, and unprivileged nodes.

# (from within vagrant env, use `vagrant ssh` to enter)
ubuntu@ubuntu-xenial:~$ cd quorum-examples/7nodes

$ ./init.sh
# (output condensed for clarity)
[*] Cleaning up temporary data directories
[*] Configuring node 1
[*] Configuring node 2 as block maker and voter
[*] Configuring node 3
[*] Configuring node 4 as voter
[*] Configuring node 5 as voter
[*] Configuring node 6
[*] Configuring node 7

$ ./start.sh
[*] Starting Constellation nodes
[*] Starting bootnode... waiting... done
[*] Starting node 1
[*] Starting node 2
[*] Starting node 3
[*] Starting node 4
[*] Starting node 5
[*] Starting node 6
[*] Starting node 7
[*] Unlocking account and sending first transaction
Contract transaction send: TransactionHash: 0xbfb7bfb97ba9bacbf768e67ac8ef05e4ac6960fc1eeb6ab38247db91448b8ec6 waiting to be mined...
true

We now have a 7-node Quorum cluster with a private smart contract (SimpleStorage) sent from node 1 "for" node 7 (denoted by the public key passed via privateFor: ["ROAZBWtSacxXQrOe3FGAqJDyJjFePR5ce4TSIzmJ0Bc="] in the sendTransaction call).

Connect to any of the nodes and inspect them using the following commands:

$ geth attach ipc:qdata/dd1/geth.ipc
$ geth attach ipc:qdata/dd2/geth.ipc
...
$ geth attach ipc:qdata/dd7/geth.ipc


# e.g.

$ geth attach ipc:qdata/dd2/geth.ipc
Welcome to the Geth JavaScript console!

instance: Geth/v1.5.0-unstable/linux/go1.7.3
coinbase: 0xca843569e3427144cead5e4d5999a3d0ccf92b8e
at block: 679 (Tue, 15 Nov 2016 00:01:05 UTC)
 datadir: /home/ubuntu/quorum-examples/7nodes/qdata/dd2
 modules: admin:1.0 debug:1.0 eth:1.0 net:1.0 personal:1.0 quorum:1.0 rpc:1.0 txpool:1.0 web3:1.0

> quorum.nodeInfo
{
  blockMakerAccount: "0xca843569e3427144cead5e4d5999a3d0ccf92b8e",
  blockmakestrategy: {
    maxblocktime: 10,
    minblocktime: 3,
    status: "active",
    type: "deadline"
  },
  canCreateBlocks: true,
  canVote: true,
  voteAccount: "0x0fbdc686b912d7722dc86510934589e0aaf3b55a"
}

# let's look at the private txn created earlier:
> eth.getTransaction("0xbfb7bfb97ba9bacbf768e67ac8ef05e4ac6960fc1eeb6ab38247db91448b8ec6")
{
  blockHash: "0xb6aec633ef1f79daddc071bec8a56b7099ab08ac9ff2dc2764ffb34d5a8d15f8",
  blockNumber: 1,
  from: "0xed9d02e382b34818e88b88a309c7fe71e65f419d",
  gas: 300000,
  gasPrice: 0,
  hash: "0xbfb7bfb97ba9bacbf768e67ac8ef05e4ac6960fc1eeb6ab38247db91448b8ec6",
  input: "0x9820c1a5869713757565daede6fcec57f3a6b45d659e59e72c98c531dcba9ed206fd0012c75ce72dc8b48cd079ac08536d3214b1a4043da8cea85be858b39c1d",
  nonce: 0,
  r: "0x226615349dc143a26852d91d2dff1e57b4259b576f675b06173e9972850089e7",
  s: "0x45d74765c5400c5c280dd6285a84032bdcb1de85a846e87b57e9e0cedad6c427",
  to: null,
  transactionIndex: 1,
  v: "0x25",
  value: 0
}

Note in particular the v field of "0x25" (37 in decimal) which marks this transaction as having a private payload (input).

Demonstrating Privacy

Documentation detailing steps to demonstrate the privacy features of Quorum can be found in quorum-examples/7nodes/README.

Further Reading

Further documentation can be found in the docs folder and on the wiki.

See also

• Quorum: this repository
• Constellation: peer-to-peer encrypted message exchange for transaction privacy
• Raft Consensus Documentation
• quorum-examples: example quorum clusters
• Quorum Wiki

Third Party Tools/Libraries

The following Quorum-related libraries/applications have been created by Third Parties and as such are not specifically endorsed by J.P. Morgan. A big thanks to the developers for improving the tooling around Quorum!

• Quorum-Genesis - A simple CL utility for Quorum to help populate the genesis file with voters and makers
• QuorumNetworkManager - makes creating & managing Quorum networks easy
• web3j-quorum - an extension to the web3j Java library providing support for the Quorum API
• Nethereum Quorum - a .net Quorum adapter
• ERC20 REST service - a Quorum-supported RESTful service for creating and managing ERC-20 tokens

Contributing

Thank you for your interest in contributing to Quorum!

Quorum is built on open source and we invite you to contribute enhancements. Upon review you will be required to complete a Contributor License Agreement (CLA) before we are able to merge. If you have any questions about the contribution process, please feel free to send an email to quorum_info@jpmorgan.com.

License

The go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The go-ethereum binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.

Documentation

Overview

Package ethereum defines interfaces for interacting with Ethereum.

Index

• type CallMsg
• type ChainHeadEventer
• type ChainReader
• type ChainStateReader
• type ChainSyncReader
• type ContractCaller
• type FilterQuery
• type GasEstimator
• type GasPricer
• type LogFilterer
• type PendingContractCaller
• type PendingStateEventer
• type PendingStateReader
• type Subscription
• type SyncProgress
• type TransactionSender

Types

type CallMsg

type CallMsg struct {
	From     common.Address  // the sender of the 'transaction'
	To       *common.Address // the destination contract (nil for contract creation)
	Gas      *big.Int        // if nil, the call executes with near-infinite gas
	GasPrice *big.Int        // wei <-> gas exchange ratio
	Value    *big.Int        // amount of wei sent along with the call
	Data     []byte          // input data, usually an ABI-encoded contract method invocation
}

CallMsg contains parameters for contract calls.

type ChainHeadEventer

type ChainHeadEventer interface {
	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
}

A ChainHeadEventer returns notifications whenever the canonical head block is updated.

type ChainReader

type ChainReader interface {
	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)
	TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, error)
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}

ChainReader provides access to the blockchain. The methods in this interface access raw data from either the canonical chain (when requesting by block number) or any blockchain fork that was previously downloaded and processed by the node. The block number argument can be nil to select the latest canonical block. Reading block headers should be preferred over full blocks whenever possible.

type ChainStateReader

type ChainStateReader interface {
	BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
	StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
	NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
}

ChainStateReader wraps access to the state trie of the canonical blockchain. Note that implementations of the interface may be unable to return state values for old blocks. In many cases, using CallContract can be preferable to reading raw contract storage.

type ChainSyncReader

type ChainSyncReader interface {
	SyncProgress(ctx context.Context) (*SyncProgress, error)
}

ChainSyncReader wraps access to the node's current sync status. If there's no sync currently running, it returns nil.

type ContractCaller

type ContractCaller interface {
	CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
}

A ContractCaller provides contract calls, essentially transactions that are executed by the EVM but not mined into the blockchain. ContractCall is a low-level method to execute such calls. For applications which are structured around specific contracts, the abigen tool provides a nicer, properly typed way to perform calls.

type FilterQuery

type FilterQuery struct {
	FromBlock *big.Int         // beginning of the queried range, nil means genesis block
	ToBlock   *big.Int         // end of the range, nil means latest block
	Addresses []common.Address // restricts matches to events created by specific contracts

	// The Topic list restricts matches to particular event topics. Each event has a list
	// of topics. Topics matches a prefix of that list. An empty element slice matches any
	// topic. Non-empty elements represent an alternative that matches any of the
	// contained topics.
	//
	// Examples:
	// {} or nil          matches any topic list
	// {{A}}              matches topic A in first position
	// {{}, {B}}          matches any topic in first position, B in second position
	// {{A}}, {B}}        matches topic A in first position, B in second position
	// {{A, B}}, {C, D}}  matches topic (A OR B) in first position, (C OR D) in second position
	Topics [][]common.Hash
}

FilterQuery contains options for contact log filtering.

type GasEstimator

type GasEstimator interface {
	EstimateGas(ctx context.Context, call CallMsg) (usedGas *big.Int, err error)
}

GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a specific transaction based on the pending state. There is no guarantee that this is the true gas limit requirement as other transactions may be added or removed by miners, but it should provide a basis for setting a reasonable default.

type GasPricer

type GasPricer interface {
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
}

GasPricer wraps the gas price oracle, which monitors the blockchain to determine the optimal gas price given current fee market conditions.

type LogFilterer

type LogFilterer interface {
	FilterLogs(ctx context.Context, q FilterQuery) ([]vm.Log, error)
	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- vm.Log) (Subscription, error)
}

LogFilterer provides access to contract log events using a one-off query or continuous event subscription.

type PendingContractCaller

type PendingContractCaller interface {
	PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
}

PendingContractCaller can be used to perform calls against the pending state.

type PendingStateEventer

type PendingStateEventer interface {
	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
}

A PendingStateEventer provides access to real time notifications about changes to the pending state.

type PendingStateReader

type PendingStateReader interface {
	PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
	PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	PendingTransactionCount(ctx context.Context) (uint, error)
}

A PendingStateReader provides access to the pending state, which is the result of all known executable transactions which have not yet been included in the blockchain. It is commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value transfers) initiated by the user. The PendingNonceAt operation is a good way to retrieve the next available transaction nonce for a specific account.

type Subscription

type Subscription interface {
	// Unsubscribe cancels the sending of events to the data channel
	// and closes the error channel.
	Unsubscribe()
	// Err returns the subscription error channel. The error channel receives
	// a value if there is an issue with the subscription (e.g. the network connection
	// delivering the events has been closed). Only one value will ever be sent.
	// The error channel is closed by Unsubscribe.
	Err() <-chan error
}

Subscription represents an event subscription where events are delivered on a data channel.

type SyncProgress

type SyncProgress struct {
	StartingBlock uint64 // Block number where sync began
	CurrentBlock  uint64 // Current block number where sync is at
	HighestBlock  uint64 // Highest alleged block number in the chain
	PulledStates  uint64 // Number of state trie entries already downloaded
	KnownStates   uint64 // Total number os state trie entries known about
}

SyncProgress gives progress indications when the node is synchronising with the Ethereum network.

type TransactionSender

type TransactionSender interface {
	SendTransaction(ctx context.Context, tx *types.Transaction) error
}

TransactionSender wraps transaction sending. The SendTransaction method injects a signed transaction into the pending transaction pool for execution. If the transaction was a contract creation, the TransactionReceipt method can be used to retrieve the contract address after the transaction has been mined.

The transaction must be signed and have a valid nonce to be included. Consumers of the API can use package accounts to maintain local private keys and need can retrieve the next available nonce using PendingNonceAt.