RAILGUN Engine SDK

Wallet framework for RAILGUN smart contracts and private balances on Ethereum and more.

Read about RAILGUN: www.railgun.org

For simple implementations, use RAILGUN Wallet SDK.

Installing

With NPM

npm install @railgun-community/engine

With Yarn

yarn add @railgun-community/engine

API

There are many APIs that can be imported via import { } from '@railgun-community/engine' but the most important is RailgunEngine.

General

Constructors

• RailgunEngine.initForWallet() (static method) creates an instance
• RailgunEngine.initForPOINode() (static method) creates an instance

Others

• RailgunEngine.setEngineDebugger() (static method)
• railgunEngine.loadNetwork() (instance method)
• railgunEngine.unload() (instance method)

Wallet management

RAILGUN Wallet

• railgunEngine.createWalletFromMnemonic() (instance method)
• railgunEngine.loadExistingWallet() (instance method)

View-only RAILGUN Wallet

• railgunEngine.createViewOnlyWalletFromShareableViewingKey() (instance method)
• railgunEngine.loadExistingViewOnlyWallet() (instance method)

Teardown

• railgunEngine.unloadWallet() (instance method)
• railgunEngine.deleteWallet() (instance method)

Scanning

"Scanning" consists of algorithms that fetch smart contract data to (re)build merkletree data structures, while also attempting to decrypt notes on the merkletrees, in order to calculate wallet balances.

• railgunEngine.scanContractHistory() (instance method)
• railgunEngine.emitScanEventHistoryComplete() (instance method)
• railgunEngine.syncRailgunTransactionsV2() (instance method)
• railgunEngine.fullRescanUTXOMerkletreesAndWallets() (instance method)
• railgunEngine.fullResetTXIDMerkletreesV2() (instance method)
• railgunEngine.resetRailgunTxidsAfterTxidIndex() (instance method)

Getters

Merkletrees

• railgunEngine.getUTXOMerkletree() (instance method)
• railgunEngine.getTXIDMerkletree() (instance method)

Others

• railgunEngine.getLatestRailgunTxidData() (instance method)
• railgunEngine.getCompletedTxidFromNullifiers() (instance method)
• railgunEngine.getAllShieldCommitments() (instance method)

Utilities

• Mnemonic.generate() (static method)
• Mnemonic.validate() (static method)
• Mnemonic.toSeed() (static method)
• Mnemonic.toEntropy() (static method)
• Mnemonic.fromEntropy() (static method)
• Mnemonic.to0xPrivateKey() (static method)
• Mnemonic.to0xAddress() (static method)
• BlindedCommitment.getForUnshield() (static method)
• BlindedCommitment.getForShieldOrTransact() (static method)
• ByteUtils.u8ToBigInt() (static method)
• ByteUtils.hexToBigInt() (static method)
• ByteUtils.nToBytes() (static method)
• ByteUtils.nToHex() (static method)
• ByteUtils.bytesToN() (static method)
• ByteUtils.hexStringToBytes() (static method)
• ByteUtils.randomHex() (static method)
• ByteUtils.hexlify() (static method)
• ByteUtils.arrayify() (static method)
• ByteUtils.formatToByteLength() (static method)
• ByteUtils.hexToBytes() (static method)
• getGlobalTreePosition()
• convertTransactionStructToCommitmentSummary()
• encryptJSONDataWithSharedKey()
• tryDecryptJSONDataWithSharedKey()
• getPublicViewingKey()

Types

• AddressData for encoding 0zk addresses
• SpendingPublicKey
• SpendingKeyPair
• ViewingKeyPair
• MerklerootValidator
• MerkletreeLeaf
• InvalidMerklerootDetails
• MerkletreesMetadata
• POINodeInterface

Developing

Install nodejs

• Via NVM (recommended)
• Via installer

Install modules

npm install OR yarn

Compile TypeScript

npm compile OR yarn compile

Run unit tests

npm test-V2 OR yarn test-V2

Run all tests, including contract integration tests (requires Hardhat setup below)

npm run test-hardhat-V2 OR yarn test-hardhat-V2

Hardhat setup

Clone the contracts repo

git clone [email protected]:Railgun-Privacy/contract.git

Start hardhat node from the contract repo and leave it running

npm run node

In another terminal deploy the contracts to the hardhat node network

npm run deploy

The default test config should work fine here as addresses are deterministic on the hardhat node network. If you are running your own test setup you will need to use the config override file. Copy test/configOverrides.test.ts.example to test/configOverrides.test.ts and enter your own values.

You can run subsequent test runs against the same hardhat node deployment as the testing suite will use snapshots to restore hardhat back to the initial state after each test. If for some reason the testing suite is interrupted before it can restore to snapshot you will need to terminate the hardhat node process, restart it, and run the deploy test script again.

In some situations it will be useful to recompile the contract from scratch. In that case, first run npm run clean and then npm run compile, after which it is safe to re-run the node and deploy script.