What is blind signing on a Ledger and should I enable it?

Understanding Blind Signing on a Ledger

Blind signing is a feature available on Ledger hardware wallets, such as the Nano S and Nano X, that allows users to sign transactions for certain blockchain protocols that are not natively supported by the device. Normally, when you interact with decentralized applications (dApps), your Ledger verifies the transaction details before allowing you to approve it through the physical buttons on the device.

However, some blockchains like Ethereum-based networks (e.g., Binance Smart Chain, Polygon, Avalanche) or Tezos require additional functionality that isn't fully integrated into Ledger Live or the firmware of the wallet. This is where blind signing comes in — it enables the wallet to sign arbitrary data without validating the content of the transaction first.

How Does Blind Signing Work?

When blind signing is enabled, your Ledger will allow dApps to send raw transaction data directly to the wallet for approval. Instead of showing detailed transaction information (like recipient address, amount, fees), the wallet displays a generic message asking if you want to sign the provided data.

This means:

• The transaction details are not parsed by the Ledger application.
• You must trust the dApp interface to present accurate information.
• You're essentially signing what you see on the screen of your computer or phone, not what’s shown on the Ledger device.

The process involves:

• Connecting your Ledger via USB or Bluetooth.
• Opening the relevant app (like Ethereum or Tezos).
• Receiving a raw transaction request from a dApp.
• Approving the signature using the Ledger's physical buttons.

Use Cases Where Blind Signing Is Required

There are several scenarios where blind signing becomes necessary for interacting with certain decentralized platforms:

• Using non-native apps like MetaMask or Rabby with your Ledger.
• Interacting with custom smart contracts on EVM-compatible chains.
• Participating in DeFi protocols or NFT marketplaces that aren’t fully integrated with Ledger apps.
• Staking or voting on governance platforms built on unsupported chains.

For example, if you try to use Binance Smart Chain with MetaMask, you'll need to enable blind signing for the Ethereum app on your Ledger because Ledger doesn’t have a dedicated BSC app.

Risks Associated With Enabling Blind Signing

While blind signing unlocks more flexibility, it also introduces significant risks:

• Phishing attacks: Malicious dApps could trick you into signing transactions that drain funds from your wallet.
• Transaction manipulation: If the dApp front-end is compromised, you may unknowingly sign a harmful transaction.
• Lack of transparency: Since the Ledger doesn’t show the actual transaction content, you can't verify the destination address or value being sent.

Therefore, enabling this feature should be done with caution and only when necessary.

How to Enable Blind Signing on Your Ledger Device

To enable blind signing, follow these steps:

• Connect your Ledger device to your computer.
• Open Ledger Live and go to the Settings menu.
• Navigate to the Security section.
• Look for the option labeled 'Blind signing policy'.
• Change the setting from 'Strict' to 'Prompt' or 'Always accept' depending on your needs.

After changing this setting, you’ll need to open the relevant application (e.g., Ethereum) each time you interact with a dApp that requires blind signing.

You may also need to manually toggle the setting back to strict after completing the interaction to reduce risk exposure.

Should I Enable Blind Signing? Considerations Before Proceeding

Before enabling blind signing, ask yourself the following questions:

• Are you interacting with trusted platforms?
• Do you fully understand the risks involved?
• Can you afford to lose funds if something goes wrong?

If you're an advanced user who frequently uses DeFi or non-supported chains, then enabling blind signing might be necessary. However, if you primarily transact on native apps and chains supported by Ledger, there’s no need to activate this feature.

Additionally, always ensure that:

• Your Ledger firmware is up to date.
• You’re using a reputable browser extension like MetaMask.
• You have two-factor authentication enabled on all accounts.

Frequently Asked Questions (FAQs)

Q: What happens if I accidentally sign a malicious transaction with blind signing enabled?A: If you approve a malicious transaction while blind signing is active, your funds could be transferred to an attacker’s wallet. Always double-check the dApp interface and ensure you're interacting with verified contracts.

Q: Can I enable blind signing for specific apps only?A: No, the blind signing setting applies globally to the selected application (e.g., Ethereum). Once enabled, any dApp requesting a signature for that chain will trigger the blind signing prompt.

Q: Is blind signing the same as regular transaction signing on a Ledger?A: No. Regular signing involves Ledger parsing and displaying transaction details. Blind signing skips this verification step, making it less secure but more flexible.

Q: How do I know if a dApp requires blind signing?A: If the dApp prompts you to enable blind signing or shows an unsigned transaction without details in your Ledger, it likely relies on this feature. Check the dApp’s documentation or support forums for guidance.