Claim a Deterministically Derived PKP Using a User ID

This code demonstrates how to use a custom user ID to deterministically generate a PKP. This enables us to know the PKP public key and Ethereum address before minting the PKP.

You can read more about claimable keys here, and how to claim keys using a Lit Action here.

Understanding the Implementation

1. Using an imported Ethereum private key, connect the wallet to the Lit RPC endpoint Chronicle Yellowstone. This will be used to pay for Lit usage
2. Use the LitNodeClient to connect to the Lit network
3. Connect the LitContracts client to the Lit network (datil-test in this case)
4. If not provided in the .env file: Mint a capacityCreditsNFT and define the request limit and expiration date
5. Create a capacityDelegationAuthSig. Any network costs will be undertaken by the dAppOwnerWallet
6. Generate the session signatures via an AuthSig (Authentication Signature)
7. Create a userId by combining an arbitrary string, which could be a username, and the current timestamp. This is to ensure the userId is unique
8. Execute the Lit Action. The Lit Action will derive a keyId from the userId
9. Use the LitContracts.pubkeyRouterContract.read.getDerivedPubkey method to derive a PKP public key from the keyId
10. Use the litContractClient.pkpNftContract.write.claimAndMint method to claim the derived PKP public key, and mint a new PKP that has the same public key
11. Wait for the transaction to finish, and derive the PKP public key, token ID, and ETH address from the transaction receipt

Running the Example

Install the Dependencies

In this directory, lit-action-claim-key/nodejs, run yarn to install the project dependencies.

Setting Up the .env File

Make a copy of the provided .env.example file and name it .env:

cp .env.example .env

Within the .env there are the ENVs:

1. ETHEREUM_PRIVATE_KEY - Required
   • Must have Lit tstLPX tokens on the Chronicle Yellowstone blockchain
     • Faucet for Chronicle Yellowstone
   • Will be used to mint the PKP and pay for Lit usage
2. LIT_CAPACITY_CREDIT_TOKEN_ID - Optional
   • If not provided, a new capacityCreditsNFT will be minted and used. This enables the ETHEREUM_PRIVATE_KEY to pay for Lit usage

Running the Tests

After the .env is configured, the test NPM script in the package.json will run a test that executes the example script. Run it using:

yarn test