Prokey Link

Prokey Link is a platform for integrating Prokey device into 3rd party services. It provides functionalities like accessing public keys and sign messages or transactions.

Installation

There is no need to install any package for using link layer.

Prokey Link is using browser cross-origin communication method to send or receive data from other tabs.

Basically you just need to open Prokey Link and post your request to the tab.

Usage

before sending any request, one link tab must be opened like this:

const popup = window.open('https://link.prokey.io');

• Sending Request

Now popup is a Window type object that you can use popup.postMessage() method to communicate with link layer.

const popup = window.open('https://link.prokey.io');
popup.postMessage({ param, type }, 'https://link.prokey.io');

• Receiving Results

The process of communication between your tab and link layer is asynchronous.

You should also listen and wait for the message that is being sent from the link.

const handleMessage = event => {
  if (event.origin.startsWith('https://link.prokey.io')) {
    window.removeEventListener('message', handleMessage);
    //do something with event.data
  }
};

window.addEventListener(
  'message',
  event => handleMessage(event),
  false
);

Command Types

There are some certain command types that you can send to link and run it on device. All results are objects.

Key	Type	Description
GetEthereumPublicKey	string	returns xpub
GetAddress	string	returns address
SignTransaction	string	returns v,r,s
SignMessage	string	returns signature,address

Arguments Format

• GetEthereumPublicKey

Key	Type	Description
path	string	a BIP44 path for requested public key

popup.postMessage(
  { param: { path: "m/44'/60'/0'/0/0" }, type: 'GetEthereumPublicKey' },
  'https://link.prokey.io'
);

• GetAddress

Key	Type	Description
path	string	a BIP44 path for requested address

popup.postMessage(
  { param: { path: "m/44'/60'/0'/0/0" }, type: 'GetAddress' },
  'https://link.prokey.io'
);

• SignTransaction

Prokey supports both legacy and EIP1559 sign methods depending on the parameters it receives.

Key	Type	Description
path	string	a BIP44 path to sign with
transaction	object	common : to: string value: string gasLimit: string nonce: string data?: string chainId: number for legacy: gasPrice: string for eip1559: maxPriorityFeePerGas: string maxFeePerGas: string

const transaction = {
    "chainId": "0x4",
    "nonce": "0x2",
    "maxPriorityFeePerGas": "0x59682f00",
    "maxFeePerGas": "0x98e16788",
    "gasLimit": "0x5208",
    "to": "0xbd20f6f5f1616947a39e11926e78ec94817b3931",
    "value": "0x49e57d6354000",
    "data": "0x",
}

popup.postMessage(
  { param: { path: "m/44'/60'/0'/0/0" , transaction }, type: 'SignTransaction' },
  'https://link.prokey.io'
);

• SignMessage

Key	Type	Description
path	string	a BIP44 path to sign with
message	string	-

popup.postMessage(
  { param: { path: "m/44'/60'/0'/0/0" , message: "This is my msg." }, type: 'SignMessage' },
  'https://link.prokey.io'
);

After any operation the link tab will be closed and it should be opened as mentioned above for the next operation.

Example

A recommended method for sending and receiving requests:

const handleMessage = (event, resolve) => {
  if (event.origin.startsWith(PROKEY_LINK_URL)) {
    window.removeEventListener('message', handleMessage);
    resolve(event.data);
  }
};

const openProkeyLink = (param, type) =>
  new Promise((resolve) => {
    const popup = window.open(PROKEY_LINK_URL);
    setTimeout(() => {
      popup.postMessage({ param, type }, PROKEY_LINK_URL);
    }, 2000);
    window.addEventListener('message', (event) => handleMessage(event, resolve), false);
  });

const params = {
  path: "m/44'/60'/0'/0/0",
  message: 'my message',
};
const { signature, address } = await openProkeyLink(params, 'SignMessage');