EIP-712 Message Hash Calculator

A simple utility to calculate EIP-712 message hashes (specifically the Struct Hash) for verifying transactions on Ledger hardware wallets (like Nano S or Nano X).

This tool is particularly useful for transactions where the Ledger displays a "Message Hash" during blind signing that needs to be manually verified.

Prerequisites

To run this tool, you need to have the following installed on your system:

• Node.js: (Version 16 or higher recommended)
• npm: (Usually comes bundled with Node.js)

Installation

1. Clone or download this repository.
2. Navigate to the project directory:

   cd eip712_verifier

3. Install the required dependencies:

   npm install

Usage

Run the script using node and provide the EIP-712 JSON object as a single string argument.

Option 1: Basic Command

node index.js '<JSON_STRING>'

Option 2: Using npm link

In the project directory, run:

sudo npm link

Now you can call the tool from anywhere using:

eip712_verifier '<JSON_STRING>'

Option 3: Running with npx

You can also run it directly using npx.

npx eip712_verifier '<JSON_STRING>'

How it Works

The tool uses the ethers.js library to parse the EIP-712 typed data. It specifically calculates the Struct Hash of the message portion, as this is the hash displayed by Ledger devices during the blind signing process for EIP-712 messages.

Dependencies

• ethers: Used for EIP-712 encoding and hashing.

License

This project is released into the public domain under the Unlicense.