Quorum is an Ethereum-based distributed ledger protocol that has been developed for a permissioned implementation of Ethereum to support transaction and contract privacy.

Features

  • Private/Permissioned blockchain, based on geth (Go implementation of Ethereum)
  • Performance: upto 100s of TPS
  • Focus on privacy - Reveal transactions only to those who are party to the transaction.

Ethereum compatible

Quorum is a fork of ethereum itself. So it is much easier to “port” the smart contracts from Ethereum to Quorum. All the knowledge of Solidity and EVM can be carried over.

Quorum will be kept up to date with future geth releases.

Permissioned

Permissioned network means that the node will not “talk” to any random node on the network.

When --permissioned flag is passed when starting the node, it looks for a “white list” of nodes, that this node will accept incoming connections from and make outgoing connections to.

This mean we have explicit control over which node we allow in our network.

The nodes also have roles “maker” and “voter”. As the name suggests, only “maker” can create new blocks.

Privacy

How does Quorum handle privacy ? By dividing the information into two : public and private. Please remember that public and private does not refer to public blockchain. It refers to whether the information is accessible to everyone (thus “public”) or not (“private”)

Every node does not have full state DB. Only “admin” and “regulator” node have full DB. regulator node is a node that is party to all transactions, that is why it has complete private state DB.

Each node:

  • has 2 DBs - Public state, and private state.
  • validates all public transactions
  • Execute smart contract code for private transactions where they are party.
  • Skip smart contract code execution for “other” private transactions.

Additionally, “private smart contract can not change public state” (Nor can it create public contract i.e. Once private always private. Switching sides not allowed.)

Performance

Since this is a permissioned private blockchain, there is no need for PoW. So using other consensus algorithms, Quorum is able to achieve better performance.

Voting based consensus algorithm (QuorumChain) Implemented as a smart contract. Thus allowing to upgrade the consensus.

References