Signing a message on Ethereum is often required to prove address ownership to exchanges, services, or platforms—without sending a transaction or paying gas fees.

This guide explains how to sign an Ethereum message securely using your BitBox02 and Rabby Wallet, with verification performed directly on the BitBox02 display.

What You Will Achieve

By following this guide, you will:

• Sign an Ethereum message without exposing private keys
• Verify the message and address on the BitBox02 screen
• Obtain a cryptographic signature that can be shared with third parties

Prerequisites

Before you begin, ensure the following requirements are met:

• BitBox02
  Connected, unlocked, and ready for use
• BitBoxApp
  Closed during the signing process
• BitBoxBridge installed
  Required for browser-based communication
  Install guide: How to install the BitBoxBridge 
• Google Chrome or Brave browser
  Other browsers are not supported for this flow
• Rabby Wallet browser extension
  Installed, set up, and unlocked
  Connection guide: How to connect your BitBox02 to Rabby Wallet 
• Ethereum account available in Rabby Wallet
  The address you want to prove ownership of must be currently selected in the Rabby Wallet extension

Step-by-step guide

Step 1: Unlock Rabby Wallet

1. Open your browser (Chrome or Brave).
2. Click the Rabby Wallet extension.
3. Unlock it using your password.

Ensure the correct Ethereum address is selected before continuing.

Step 2: Open the Etherscan Message Signing Page

1. Visit the following page:
   https://etherscan.io/verifiedSignatures#
2. In the top-right corner, click “Sign Message”.

3. A disclaimer will appear indicating that this feature is provided “as is.”
   Click OK to proceed.

Step 3: Connect Rabby Wallet

1. A “Connect a Wallet” window will appear.
2. Select Rabby Wallet.

3. If Rabby Wallet is already unlocked, Etherscan will automatically populate the currently selected Ethereum address.

Verify that this address matches the one you intend to use.

Step 4: Enter the Message to Be Signed

1. Paste the exact message text provided by the exchange or service.
2. The message must match character-for-character, including spaces and punctuation.
   
   Example:

How to Sign an Ethereum Message with the BitBox02

3. Click Sign Message.

Step 5: Confirm in Rabby Wallet

1. A Rabby Wallet notification window will open.
2. Review the address and message.
3. Click Begin signing process.
4. This action forwards the request to your BitBox02.

Step 6: Verify and Confirm on the BitBox02

1. On the BitBox02 display, confirm:
   1. The blockchain: Ethereum
   2. The signing address
2. Approve the address by tapping the checkmark.
3. The message text will appear on the BitBox02 screen.
4. Carefully verify the message.
5. Confirm by touching both corners of the BitBox02 simultaneously.

This step ensures that the message is signed only after on-device verification.

Step 7: Publish the Signed Message

1. You will be returned to Etherscan.
2. A “Publish Signed Message” window will appear.
3. Review all details and note the Signature Hash.
   1. Copy the signature hash if required by the exchange.
4. Click Publish.

You should now see a confirmation stating that the message signature was successfully verified.

Final Result

You now have a verified Ethereum message signature that can be shared with the requesting service to confirm address ownership.

FAQ

What is Ethereum message signing used for?

Message signing is commonly used to prove ownership of an Ethereum address without sending a transaction or revealing private keys.

Does signing a message cost gas?

No. Message signing is an off-chain operation and does not require gas fees.

Can I use browsers other than Chrome or Brave?

Chrome or Brave is required because Rabby Wallet is designed to work exclusively—and most reliably—with these browsers.

Is my private key ever shared?

No. The private key never leaves the BitBox02. All signing operations are verified and approved directly on the device.

Why must the message text be entered exactly?

Even a single extra space or character will invalidate the signature. Always copy the message exactly as provided.

What should I do with the signature hash?

Some exchanges or services require the signature hash as proof. Keep it available until the verification process is complete.