Beware of the eth_sign Blind Signing Trap: Principles, Risks, and Protective Measures

Recently, cases of eth_sign blind signing scams have been frequent, with many users unknowingly signing seemingly harmless eth_sign signatures on suspicious websites, resulting in the theft of wallet assets. To help everyone better understand this scam technique, we first need to understand the nature of eth_sign signatures.

What is eth_sign Signature

In the Ethereum ecosystem, eth_sign is a widely used signing method that allows users to sign messages with their private keys. This mechanism is a key part of blockchain transactions and can prove that a specific account initiated a transaction. In simple terms, it's like signing a document, indicating that you agree with or support its content.

However, there is an easily overlooked issue during the use of eth_sign, which is the so-called "blind signing". When you use eth_sign to sign, you might not fully understand the content of the signature and cannot verify what the signature specifically represents in reverse. This is because the input for eth_sign is raw characters, rather than a human-readable format. It's like signing a contract in a foreign language that you cannot understand, which is also why it is referred to as "blind signing".

Common Scamming Techniques

After understanding the concepts of eth_sign signatures and blind signatures, let's delve into the potential risks of eth_sign and how to prevent such blind signature scams.

Since eth_sign can be used to sign various types of messages, including transactions and smart contract instructions, a malicious party may induce you to sign a message that you do not fully understand, resulting in the transfer of your assets. Worse, they may present you with a seemingly harmless message to sign, but in reality, it could be an operational instruction, and once you sign it, your assets will be transferred.

In the face of this situation, how should we guard against it? In response to such fraudulent activities, a well-known wallet has upgraded its risk control system in the new version. When users access a third-party DApp and call eth_sign to sign a message, the wallet will provide a risk warning pop-up, reminding users that the current transaction may have potential risks and initiating a 15-second countdown cooling period. This design aims to give users enough time to evaluate the necessity and safety of the signing operation.

Security Recommendations

The security team reminds everyone:

• Be vigilant about all requests that require eth_sign signatures, especially those from unknown or untrusted sources. If you have doubts about the authenticity or purpose of a request, do not sign it lightly.
• Ensure that the messages or transaction requests you handle come from trusted sources, such as official websites, official social media, or verified communication channels. Never trust links, emails, or private messages from unknown sources.

By understanding how eth_sign signatures work and their potential risks, and taking appropriate protective measures, we can better safeguard the security of our digital assets. In the blockchain world, remaining vigilant and cautious is always the best defense strategy.