prove-solana-wallet

This library proveTransactions ownership of a Solana wallet to off-chain verifiers.

It is compatible with standard browser wallet adapters, such as sol-wallet-adapter, and can be extended to others.

Install

npm install @identity.com/prove-solana-wallet

or

yarn add @identity.com/prove-solana-wallet

Usage

prove ownership of a keypair using a signed message

prover side:

const {create} = require('@identity.com/prove-solana-wallet');
const nonce = `${new Date().getTime()}`;
const proof = await create(myKeypair, nonce);

Verifier side:

const {verify} = require('@identity.com/prove-solana-wallet');
const message = timestamp;
verify(expectedPublicKey, proof, message);

prove ownership of a keypair using a transaction

prover side:

const {proveTransaction} = require('@identity.com/prove-solana-wallet');
const proof = await proveTransaction(myKeypair);

Verifier side:

const {verifyTransaction} = require('@identity.com/prove-solana-wallet');
await verifyTransaction(proof, expectedPublicKey);

prove ownership of an external wallet (e.g. sol-wallet-adapter). See here for more details.

prover side:

const {proveTransaction} = require('@identity.com/prove-solana-wallet');
import Wallet from "@project-serum/sol-wallet-adapter";

const providerUrl = 'https://www.sollet.io';
const wallet = new Wallet(providerUrl);
wallet.on('connect', async (publicKey) => {
  // once the wallet is connected, we can prove ownership
  const signer = (transaction:Transaction) => wallet.signTransaction(transaction);

  const proof = await proveTransaction(myKeypair);
});

Verifier side:

const {verifyTransaction} = require('@identity.com/prove-solana-wallet');
await verifyTransaction(proof, expectedPublicKey);

Details

Using a signed message

The create(signMessageFn, message) function signs a message with the provided signing function, then concatenates the message with the string, both in base64 encoded form, i.e. ${messageB64}.${signatureB64}.

The verify(publicKey, proof) function decodes the message and signature from the proof, and uses nacl to verify that the given public key signed the proof.

Using a zero-value transaction

The proveTransaction() function generates a zero-value transaction, and signs it with the wallet private key. For the transaction to be verified by the verifyTransaction() function, it must:

• have ony one instruction: SystemProgram.transfer
• be zero-value
• be self-to-self (i.e the sender and recipient are the same)
• have a recent blockhash on mainnet
• but not be broadcast to mainnet

These measures increase the security by reducing the likelihood that an attacker can either coerce the wallet owner to sign a transaction or intercept a broadcast one.

Configuration

The proveTransaction and verifyTransaction functions can be configured as follows:

cluster

Default: mainnet-beta

The cluster that should be used when generating and verifyTransactioning proofs

commitment

Default: confirmed

When checking that a proof transaction has not been transmitted, the commitment to be used, i.e. the degree to which the transaction is finalised by the network

supportedClusterUrls

Optional Default: empty

If the cluster is not a standard solana public cluster, this map provides the cluster URL to connect to. Use this when the proof may contain a cluster that is not recognised by solana's clusterApiUrl function.