Substrate (Polkadot)

Substrate based chains like Polkadot, Kusama and Polymesh support the following signature kinds:

• SignerPayload, serialized generic signer payload.

SignerPayload

Signs a generic signer payload. Note: converting the generic signer payload to a signable extrinsic requires fetching metadata from the targeted blockchain. Therefore it's tied to a specific network rather than the blockchain kind.

Field	Description	Type - Optional
network	A supported Substrate network.	String
kind	SignerPayload	String
payload	The unsigned hex encoded signer payload as shown below.	String

{
  "network": "Polymesh",
  "kind": "SignerPayload",
  "message": "0x0403007f87d29a4746b8e59e347c0598ad811a10c3cd8735d49cf96b75973864c8c98b0475000400386d0f0019000000e143f23803ac50e8f6f8e62695d1ce9e4e1d68aa36c1cd2cfd15340213f3423eb3b9c09f232a12c50f40e023a01f0b86d679b84748cc289534d96861ef611c67"
}

Typescript Example with polkadot{.js}

First install the polkadot{.js} SDK. You can find the full documentation here: https://polkadot.js.org/docs/

Here a code sample to generate a signature via the Dfns TypeScript SDK:

import { ApiPromise, HttpProvider } from '@polkadot/api'
import { EXTRINSIC_VERSION } from '@polkadot/types/extrinsic/v4/Extrinsic'

const walletId = 'wa-6lbfv-9esgj-xxxxxxxxxxxxxxxx'
const wallet = await dfnsClient.wallets.getWallet({ walletId })

const httpProvider = new HttpProvider(process.env.POLKADOT_NODE_URL!)
const api = await ApiPromise.create({
  provider: httpProvider,
  signer: senderWallet,
  noInitWarn: true,
})

const transaction = api.tx.balances.transferKeepAlive('5EwvHZHrKd9WYc3LByzMZW5cmxJt9VMsfYiKg5jCJb8UBfbC', 10000)
const signerPayload: any = transaction.registry.createTypeUnsafe('SignerPayload', [
  transaction,
  { version: EXTRINSIC_VERSION },
])

const res = await dfnsClient.wallets.generateSignature({
  walletId,
  body: {
    kind: 'SignerPayload',
    message: signerPayload.toHex(),
  },
})