Prove-ICP-Principal

This library proves ownership of an ICP Principal to off-chain verifiers. To create proof of ownership, a signing function must be provided that allows the user to sign some typed-data with their private key, thus proving they own the wallet. The verifier will check that the signature of the signer matches the wallet address to check, and that the contents of the signed typed-message are valid. The proof consists of a string of a base64 version of the message concatenated with a '.' and the base64 version of the signature.

Install

npm install @civic/prove-icp-principal

or

yarn add @civic/prove-icp-principal

Usage

Prove ownership of an ICP principal using Internet Identity

Prover side:

const { create } = require('@civic/prove-icp-principal');
const ownerWallet = Wallet.createRandom();

const proof = await create((domain, types, message) => wallet._signTypedData(domain, types, message), { message: '<verifierUrl>' });

Verifier side:

const { verify } = require('@civic/prove-icp-principal');
const success = await verify(expectedOwnerAddress, proof, { message: '<verifierUrl>' });

Details

The prove() function generates some typed-data, including an expiry timestamp and message and signs it with the wallet private key. For the transaction to be verified by the verify() function, it must:

• have an expiry that is before UTC now()
• be signed by the expected principal
• contain a matching message

Configuration

The prove and verify functions can be configured as follows:

domain Optionally set the domain for the signed data

Optional Default:

export const defaultDomain: TypedDataDomain = {
  name: "Proof Of ICP Principal Ownership",
  version: "1",
};

types Optionally set the types to be used in the signed data

Optional Default:

export const defaultTypes: Record<string, Array<TypedDataField>> = {
  PoWo: [
    { name: "expires", type: "string" },
    { name: "message", type: "string" },
  ],
};

message

Optional Default: empty

The message passed to check against the proof. This would normally be a nonce, or single use message to prevent the POWO from being re-used in a replay-attack.