Hardhat Project: ECRecover Usability in the Hedera Network

This project investigates the relationship between private key types and the usability of the ecrecover function in the Hedera Network.

Overview

Accounts with an ECDSA key pair and an EVM alias derived from them should be able to use the ecrecover function correctly, provided their key pair has not been replaced.

In the Hedera Network:

• msg.sender always returns the EVM alias associated with the user account, even if the key pairs associated with that account are replaced. This means msg.sender will remain consistent for every transaction signed by that account.
• The ecrecover function, however, returns the address associated with the actual private key used to sign the message passed to it. Therefore, after the first key pair update, ecrecover will no longer work correctly for ECDSA accounts. Despite this, msg.sender will remain unchanged and consistent.

Please note that ecrecover will never work for ED25519 accounts, regardless of the circumstances.

Running Tests

To prove these assumptions, automated tests have been prepared. To run them, follow these steps:

1. Copy .env.example to .env:

   cp .env.example .env

2. Set the environment variables in the .env file:

   HEDERA_NETWORK=https://testnet.hashio.io/api
   HEDERA_MIRRORNODE=https://testnet.mirrornode.hedera.com/api/v1/
   HEDERA_OPERATOR_KEY={Your operator Private Key - remember to keep it secret}
   HEDERA_OPERATOR_ID={Your operator id in 0.0.Z format}
   QUERY_GAS=100000
   QUERY_HBAR_PAYMENT=2
   

   Ensure you have the HEDERA_OPERATOR_KEY and HEDERA_OPERATOR_ID set, and that they have test hbars.

   • HEDERA_NETWORK: This URL is used to create transactions in the Hedera network.
   • HEDERA_MIRRORNODE: This URL is required to get the Hedera contract ID of the deployed contract (using the Hedera address as an input).
   • HEDERA_OPERATOR_KEY and HEDERA_OPERATOR_ID: These are required and should have test hbars.
   • QUERY_HBAR_PAYMENT: This is the payment for querying contract methods.
   • QUERY_GAS: This is the gas used for querying contract methods.

3. Run the following command:

REPORT_GAS=true npx hardhat test --network hedera

Contract Deployment

This repository also contains the code for a Smart Contract. This smart contract allows users to:

• Verify a signature and return the recovered address.
• Retrieve the address of the sender.

To deploy this Smart Contract, run the following command:

npx hardhat ignition deploy ./ignition/modules/ecrecover-check.deploy.ts --network hedera