How do private transactions work on Quorum
Download as PPTX, PDF1 like715 views
The document explains how private transactions operate on the Quorum blockchain, which is built on Ethereum but designed for enterprise use with support for privacy. It details the process of creating a private transaction payload that includes designated recipients and how this payload is processed through Quorum nodes and tessera nodes to ensure security and confidentiality. The document also provides a demonstration of setting up a Quorum network and resources for further exploration.
How do private transactions work on Quorum
- 1. Proprietary and Confidential © 2019 1 Syahrul Nizam, Developer Advocate Quorum meetup How do private transactions work on Quorum?
- 2. Proprietary and Confidential © 2019 2 Presented by Syahrul Nizam Developer Advocate Blockchain enthusiast with experience in creating & deploying Smart Contracts on Ethereum Proprietary and Confidential © 2019 2 Presented by Syahrul Nizam Developer Advocate Blockchain enthusiast with experience in creating & deploying Smart Contracts on Ethereum
- 3. Proprietary and Confidential © 2019 3 The innerworkings of Ethereum The Ethereum network is made up of nodes, each running an Ethereum client like Geth Miners Ethereum Node Blockchain Storage Genesis block Block 1 Block (n-1) Block n Interface Developers
- 4. Proprietary and Confidential © 2019 4 What is Quorum? 1. Quorum is a Ethereum based blockchain, designed for use by Enterprises. 2. It provides smart contract capability, much like Ethereum 3. What makes Quorum special is that it has support for private transactions, which is impossible on Ethereum (somewhat)
- 5. Proprietary and Confidential © 2019 5 Transactions in Ethereum A graphical representation of how transactions are propagated in a regular Ethereum network Application creates a transaction payload Transaction payload is compiled into solidity bytecode Transaction payload is sent via RPC or Websockets to an Etheruem node Ethereum node converts this solidity bytecode to EVM opcodes Opcodes are a set of instructions for the EVM to execute Stored on the Blockchain
- 6. Proprietary and Confidential © 2019 6 Quorum nodes A quorum node consists of two things…. A minimalist Geth node to provide EVM functionality A Tessera node for private transaction support Public DB PrivateState DB Private DB Connected Connected
- 7. Proprietary and Confidential © 2019 7 Let’s visualize the private transaction Application Layer Quorum transaction payloads are identical to Ethereum’s transaction payloads with an additional privateFor parameter Alice wishes to make a private transaction to Bob She supplies Bob’s Tessera public key in the privateFor parameter of the transaction payload:
- 8. Proprietary and Confidential © 2019 8 Sending the transaction payload The application then sends the transaction payload to Alice’s Quorum node Application Layer
- 9. Proprietary and Confidential © 2019 9 Quorum node The Quorum node detects the presence of the privateFor parameter in the transaction payload. Each Quorum node comes with it’s own paired Tessera Node ( Transaction Manager + Enclave ) Transaction Payload Geth Client Transaction Manager Enclave Quorum Node Geth Client Transaction Manager Enclave Quorum Node Tessera Node Tessera Node
- 10. Proprietary and Confidential © 2019 10 Tessera node (Alice’s) Transaction manager makes a call to the Enclave with the transaction payload Enclave verifies the transaction payload Enclave Enclave generates a random nonce(an arbitrary number) and a RMK (an arbitrary password) Transaction Manager Enclave
- 11. Proprietary and Confidential © 2019 11 Tessera node (Alice’s) Enclave EncodedABI payload is encrypted using the nonce and RMK
- 12. Proprietary and Confidential © 2019 12 Tessera node (Alice’s) Enclave Alice’s Tessera Private Key and Bob’s Tessera Public Key (supplied in transaction payload) and a random Number is used to encrypt the RMK itself Encrypted RMK and encrypted payload sent back to Alice’s TMTransaction Manager
- 13. Proprietary and Confidential © 2019 13 Tessera Node (Alice’s) Transaction Manager The transaction manager (Alice) hashes the encrypted payload, and uses the hash as a key to store the encrypted payload & encrypted RMK in the private database This same information is sent to Bob’s transaction manager and stores in his own private database Bob’s Transaction manager acknowledges receipt Alice’s transaction manager then returns hash to Alice’s Quorum node Bob’s Transaction Manager
- 14. Proprietary and Confidential © 2019 14 Quorum node (Alice’s) Alice’s Quorum node then replaces the data parameter in the transaction payload with the hash received from Alice’s transaction manager It also replaces the v value in the transactional receipt to tell other quorum nodes that it is a private transaction, and not a normal transaction with nonsensical bytecode Now the transaction can be propagated by the node into the blockchain normally as per standard Ethereum protocol. Every quorum node will receive this private transaction. Note the change in the data parameter
- 15. Proprietary and Confidential © 2019 15 Quorum network 1. All parties will receive the private transactions 2. Everyone will try to decrypt it How do nodes know that they are party to the private transaction??
- 16. Proprietary and Confidential © 2019 16 Quorum Node (Bob’s) Bob is party to the private transaction Bob’s quorum node receives a transaction receipt with a V value of 37 or 38. Bob’s quorum node then obtains the hash in the data parameter of the transaction payload Bob’s transaction manager will do a lookup for this hash and see if it exists! Transaction ManagerQuorum Node
- 17. Proprietary and Confidential © 2019 17 Tessera Node (Bob’s) Decryption Since Bob holds the transaction, he can obtain the encrypted payload and encrypted RMK in his private database Using his Tessera Private Key, he can first unencrypt the encrypted RMK Using this unencrypted RMK, he can now decrypt the encrypted transaction payload The decrypted payload is valid bytecode Bytecode sent back to Bob’s transaction manager
- 18. Proprietary and Confidential © 2019 18 Quorum Node (Bob’s) Using the unencrypted bytecode, the EVM can now do computations as per normal. Bytecode is discarded once it’s used and privateStateDB is updated accordingly to the instructions in the opcodes
- 19. Proprietary and Confidential © 2019 19 Quorum Nodes (Candice) Candice is not party to the transaction sent by Alice Candice’s quorum node receives a transaction payload with a V value of 37 or 38 Candice’s quorum node then obtains the hash in the data parameter of the transaction payload Candice’s transaction manager will look up this hash, and the corresponding encrypted data does not exist. Candice’s node skips this transaction.
- 20. Proprietary and Confidential © 2019 20 Demonstration & Code 1. Create a project on Chainstack 2. Download this repository : https://github.com/chainstack/quorum-iot-tutorial 3. Install Node.JS 4. Enjoy! Let’s spin up a Quorum network using Chainstack
- 21. Proprietary and Confidential © 2019 21 Summary Transaction Payload Quorum Node Transaction Manager Enclave TxPayload sent Send txPayload to TM Send to Enclave Return encrypted data Update PrivateDB Returns Tessera Hash Quorum Node Transaction Manager Enclave Propagates transaction with v value of 37/38 Send Encrypted data Return decrypted data as bytecode Returns Bytecode Checks for hash PrivateDB Send txPayload to TM Returns Encrypted Data (1) (2) (7) (3) (4) (5) (6) (8) (9) (10) (12) (13) (11) Send to Bob’s TM (14)
- 22. Proprietary and Confidential © 2019 22 What’s next? 1. Visit our documentation site to quickly create your own Dapp platforms https://docs.chainstack.com 2. Create an account on Chainstack (2 week trial) https://console.chainstack.com 3. Have fun! Get started with Chainstack
- 23. Proprietary and Confidential © 2019 23 Q & A
- 24. Proprietary and Confidential © 2019 24 Contact syahrul.nizam@chainstack.com Helpful links https://docs.chainstack.com https://console.chainstack.com
Editor's Notes
- #3: I’m Syahrul– developer advocate for Chainstack. I’m pretty much a blockchain enthusiasts and I love experimenting with blockchain technologies. It's fun because everything about blockchain is always changing. Hey maybe this tutorial might be outdated in 6 months and it will no longer work! The space is moving at lightspeed and whats nice is that you can always learn new things