Thor DevKit

Typescript library to aid dApp development on VeChainThor.

⚠️ Repository Notice: End-of-Life (EOL)

This repository now has reached its end-of-life (EOL). We have transitioned to brand new and comprehensive VeChain SDK that will continue to receive updates, support, and new features.

For any further questions or migration guidance, please reach out using our support portal.

Prerequisites

• Git
• Node.js: minimum version is 18.

Installation

To install the library, run:

npm i thor-devkit

Usage

Transaction

To build and sign a transaction:

import { Transaction, secp256k1 } from 'thor-devkit'

const clauses =  [{
    to: '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
    value: 10000,
    data: '0x'
}]

// calc intrinsic gas
const gas = Transaction.intrinsicGas(clauses)
console.log(gas)
// 21000

let body: Transaction.LegacyBody = {
    type: Transaction.Type.Legacy,
    chainTag: 0x9a,
    blockRef: '0x0000000000000000',
    expiration: 32,
    clauses: clauses,
    gasPriceCoef: 128,
    gas,
    dependsOn: null,
    nonce: 12345678
}

const tx = new Transaction(body)
const signingHash = tx.signingHash()
tx.signature = secp256k1.sign(signingHash, /* your private key */)

const raw = tx.encode()
const decoded = Transaction.decode(raw)

// To create a dynamic fee transaction, use the following:
let body = {
    type: Transaction.Type.DynamicFee,
    chainTag: 0x9a,
    blockRef: '0x0000000000000000',
    clauses: clauses,
    maxPriorityFeePerGas: 1000000000000,
    maxFeePerGas: 1200000000000,
    gas,
    dependsOn: null,
    nonce: 12345678
}

const tx = new Transaction(body)
const signingHash = tx.signingHash()
tx.signature = secp256k1.sign(signingHash, /* your private key */)

const raw = tx.encode()
const decoded = Transaction.decode(raw)

// To decode a transaction, use the following:
const raw = Buffer.from('51cf80808203e8c001018252088080c080', 'hex')
const unsigned = false
const decoded = Transaction.decode(raw, unsigned)

Certificate

Client side self-signed certificate:

import { Certificate, secp256k1, blake2b256 } from 'thor-devkit'

const cert: Certificate = {
    purpose: 'identification',
    payload: {
        type: 'text',
        content: 'fyi'
    },
    domain: 'localhost',
    timestamp: 1545035330,
    signer: <<<signer-address>>>
}

const jsonStr = Certificate.encode(cert)
const signature = secp256k1.sign(blake2b256(jsonStr), <<<private-key>>>)

cert.signature = '0x' + signature.toString('hex')

Certificate.verify(cert)

// certificate id
const id = '0x' + blake2b256(Certificate.encode(cert)).toString('hex')

ABI

import { abi } from 'thor-devkit'

const fn = new abi.Function({
    "constant": false,
    "inputs": [
        {
            "name": "a1",
            "type": "uint256"
        },
        {
            "name": "a2",
            "type": "string"
        }
    ],
    "name": "f1",
    "outputs": [
        {
            "name": "r1",
            "type": "address"
        },
        {
            "name": "r2",
            "type": "bytes"
        }
    ],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
})

const data = fn.encode(1, 'foo')

RLP

import { RLP } from 'thor-devkit'

// define the profile for tx clause structure
const profile: RLP.Profile = {
    name: 'clause',
    kind: [
        { name: 'to', kind: new RLP.NullableFixedBlobKind(20) },
        { name: 'value', kind: new RLP.NumericKind(32) },
        { name: 'data', kind: new RLP.BlobKind() }
    ]
}

const clause = {
    to: '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
    value: 10,
    data: '0x'
}

const rlp = new RLP(profile)

const data = rlp.encode(clause)
console.log(data.toString('hex'))
// d7947567d83b7b8d80addcb281a71d54fc7b3364ffed0a80

const obj = rlp.decode(data)
// `obj` should be identical to `clause`

Crypto methods

Hash functions

import { blake2b256, keccak256 } from 'thor-devkit'

const hash = blake2b256('hello world')
console.log(hash.toString('hex'))
// 256c83b297114d201b30179f3f0ef0cace9783622da5974326b436178aeef610

hash = keccak256('hello world')
console.log(hash.toString('hex'))
// 47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad

Secp256k1

import { secp256k1, keccak256, address } from 'thor-devkit'

const privKey = secp256k1.generatePrivateKey()
const pubKey = secp256k1.derivePublicKey(privKey)
const addr = address.fromPublicKey(pubKey)
const signature = secp256k1.sign(keccak256('hello world'), privKey)
const recoveredPubKey = secp256k1.recover(keccak256('hello world'), signature)

Mnemonic & Keystore

import { mnemonic, Keystore, HDNode } from 'thor-devkit'

// generate BIP39 mnemonic words, default to 12 words(128bit strength)
const words = mnemonic.generate()

// derive private key from mnemonic words according to BIP32, using the path `m/44'/818'/0'/0`.
// defined for VET at https://github.com/satoshilabs/slips/blob/master/slip-0044.md
const privateKey = mnemonic.derivePrivateKey(words)

// in recovery process, validation is recommended
let ok = mnemonic.validate(words)

// encrypt/decrypt private key using Ethereum's keystore scheme
const keystore = await Keystore.encrypt(privateKey, 'your password')

// throw for wrong password
const recoveredPrivateKey = await Keystore.decrypt(keystore, 'your password')

// roughly check keystore format
ok = Keystore.wellFormed(keystore)

// create BIP32 HD node from mnemonic words
const hdnode = HDNode.fromMnemonic(words)

// derive 5 child private keys
for (let i = 0; i < 5; i++) {
    let child = hdnode.derive(i)
    // get child private key
    // child.privateKey
}

// or create HD node from xpub
const pub = Buffer.from('04dc40b4324626eb393dbf77b6930e915dcca6297b42508adb743674a8ad5c69a046010f801a62cb945a6cb137a050cefaba0572429fc4afc57df825bfca2f219a', 'hex')
const chainCode = Buffer.from('105da5578eb3228655a8abe70bf4c317e525c7f7bb333634f5b7d1f70e111a33', 'hex')
hdnode = HDNode.fromPublicKey(pub, chainCode)
// derive 5 child public keys
for (let i = 0; i < 5; i++) {
    let child = hdnode.derive(i)
    // get child public key
    // child.publicKey
}

License

Thor DevKit is licensed under the MIT License.