PIVX Shield

WASM library for interoperation with the PIVX Shield sapling protocol. It supports:

Generating addresses with the zip32 protocol,
Shield and transparent transactions,
Multicore support with backwards compatibility for older browsers
Transaction progress status
The ability to save and load the sync status

Getting started

Install

To install the library, simply run npm i pivx-shield. Then import it in your project with

import { PIVXShield } from "pivx-shield";

Examples

To use the class, it must first be synced with:

import { PIVXShield as Shield } from "pivx-shield";

// This is an array of 64 random bytes, usually derived from a Seed phrase
// For instance with https://github.com/bitcoinjs/bip39
const yourSeed = ...;
const shield = await Shield.create({
	seed: yourSeed,
	// This should be the block of birth of the wallet.
	// Put 0 if you don't know when it was created,
	// If you have to guess, pick a date when you definetely
	// didn't have the wallet
	blockHeight: 1164767,
	coinType: 1, // Testnet
	accoutnIndex: 0,
});
// getLastSyncedBlock will start from the first checkpoint it finds. 
for (let block = shield.getLastSyncedBlock();  block < current_block_height; block++)  {
	// You need to provide a function that fetches block information
	// For example with a simple GET request to a blockbook explorer
	// https://testnet.rockdev.org/api/v2/block/1164637
	const blockData = your_fetch_block_function(block);
	await shield.handleBlock(blockData);
}
console.log(shield.getBalance());
console.log(await shield.getNewAddress());

You can also save and load the public data, for a faster sync

// This return a string with the public shield data
const data = await shield.save();
localStorage.setItem("shield", data);

const data = localStorage.getItem("shield");
const seed = ...;
const shield = await Shield.create({
	data,
	seed,
	// testnet
	coinType: 1,
	accountIndex: 0,
});

// Will return the block from when save was called
console.log(shield.getLastSyncedBlock());

To create a transaction,

import { PIVXShield as Shield } from "pivx-shield";

const shield = await Shield.create({...});
// Sync omitted

// The library provides a hex encoded signed transaction, ready to be broadcast to the network.
// For example, with a standard PIVX node, `sendrawtransaction` can be used
// For more info,
// https://github.com/PIVX-Project/PIVX/wiki/Raw-Transactions#user-content-createrawtransaction_txidtxidvoutn_addressamount
const { hex, txid }  = await shield.createTransaction({
	// Transparent addresses are supported as well
	address: "ptestsapling1s23gkjxqnedkptdvp8qn3m57z0meq2530qxwe8w7x9sdz05xg5yu8wh7534memvjwqntw8mzr3w",
	// 50 tPIV
	amount: 50 * 10**8,
	useShieldInputs: true,
});

const success = your_send_transaction_method(hex);
if (success) {
	shield.finalizeTransaction(txid);
} else {
	shield.discardTransaction(txid);
}

Contribuiting

PRs are welcome! Write tests and then make sure to run cargo fmt before submitting

Compile

To compile, run make. This will generate two versions: pkg/ and pkg_multicore/. Then, run npm i /path/to/this/project/js/, to install the javascript wrapper in your project.

License

See LICENSE for licensing information