What exactly are you signing when blind signing?
Blind signing means putting your signature on something you cannot read. In Ethereum, the signing requests that pop up in your wallet are mostly a string of hexadecimal code beginning with 0x. You cannot actually see what you are authorizing—it could be a transfer, a token approval, or handing over control of your assets to a malicious contract.
This is not a case of "careless users." It is a fundamental problem in how wallets and DApps communicate. Below we explain what blind signing actually signs, where the risks lie, and how the industry is working to fix it.
Prerequisites
You are using an Ethereum wallet (e.g. MetaMask, imToken) to interact with a DApp.
When the wallet shows a signing request, it displays "hex data" or a "raw message" instead of a human-readable transaction description.
You know your private key is in your own hands, and signing means granting authorization.
Step 1: Confirm that your signing request falls under "blind signing"
Look at the format of the content in the wallet's signing pop-up:
Case A: The signing content is shown as a "hex string" or data starting with "0x…"
You cannot read what this data means. This is blind signing—you only know that you are "signing something," but you do not know what it is. This is the most common situation and the weakness exploited by many phishing attacks.
Case B: The signing content is shown as a human-readable transaction summary
For example, "Swap 1000 USDC for 0.42 ETH" or "Transfer 2.5 ETH to address 0x123…". This is Clear Signing. If your wallet shows this, you are not in a blind signing situation.
Completion criteria: Confirm whether your current signing request shows unreadable data or a readable summary.
Step 2: Understand what blind signing actually authorizes
The problem with blind signing is not the act of signing itself, but that you do not know what you are signing. Below are the three most common types of operations authorized through blind signing:
Operation 1: A standard transfer or transaction
You think it is a normal transfer, but the signed content may actually contain malicious parameters. An attacker can trick you into signing a message that looks harmless, but the message can actually be a transfer instruction. Once signed, funds are moved to the attacker's account.
Operation 2: Authorizing a contract to move your assets
This is the most common blind signing scenario in DeFi. You click the "Approve" or "授权" button on a DApp, and the wallet shows a signing request, but you cannot see the exact approval amount or the spender. Malicious contracts can exploit blind signing to trick users into signing an unlimited approval, which then enables draining all tokens from the wallet.
Operation 3: Complex contract calls
In DeFi, NFT minting, and similar scenarios, transaction data is often too complex for hardware wallets or standard wallets to decode fully. Users end up signing only because they "trust" the protocol. What you sign is not just a transfer—it may be a combination of multi-step operations, contract upgrades, and permission changes.
Completion criteria: Know the three core risk types of blind signing and be able to match them to real situations.
Step 3: Real-world cases of blind signing risk
Blind signing is not a theoretical risk. Here are two real security incidents:
Radiant Capital incident (October 2024): Attackers compromised an external device and replaced transaction data during the signing flow, inducing signers to sign a malicious transaction without fully reviewing the transaction details. The Safe team later stated that this incident highlights the industry-wide blind signing problem.
Phishing sites exploiting eth_sign blind signing: A large number of recent phishing attacks lure users into signing an eth_sign signature on unknown websites. Users unknowingly authorize malicious contracts, resulting in drained wallets.
Completion criteria: Recognize that blind signing is a real attack vector and is widely exploited.
Step 4: Recognize the solutions the industry is pushing
In May 2026 the Ethereum Foundation announced that Clear Signing has launched, with the goal of making "human-readable transaction signing" the default experience. The core changes are:
ERC-7730 standard: Protocols provide a "translation dictionary" for contract functions, telling wallets how to translate calldata into a human-readable transaction summary. As of May 2026, 44 protocols are covered with 346 descriptor files published, including Uniswap, Aave, and Lido.
Ledger's "E8" warning: When a transaction cannot be decoded completely, Ledger shows "E8 – Security Risk Detected," alerting users that they may be about to blind sign.
Completion criteria: Know what Clear Signing is and how to identify wallets or protocols that support clear signing.
Step 5: If you must blind sign, how to reduce the risk
In some scenarios (e.g. using a new protocol or a complex contract), blind signing is still the only viable option. If you must blind sign, take the following steps:
Use a hardware wallet: Hardware wallets isolate signing locally and require physical button confirmation, reducing the risk of remote attacks.
Sign with multiple devices: Use signing devices from different vendors (e.g. Ledger + Trezor) so that the transaction is presented on multiple devices, lowering the chance of a single device being tampered with.
Limit approval amounts: Do not choose "unlimited" when approving. Manually enter the exact amount you need.
Choose trusted DApps: Prioritize projects that have been audited, have an active community, and a long track record.
Completion criteria: Even if you must blind sign, you have taken the necessary security measures.
Common reasons for mistakes
Mistakenly believing that blind signing is the user's own fault
The main cause of blind signing is not user carelessness. The imToken security team points out that the input for eth_sign is raw characters, not something human-readable—"It is like signing a contract written in a language you cannot understand." This is a systemic interface and standards problem that is gradually being addressed through infrastructure improvements like Clear Signing.
Risk reminders
Signatures cannot be undone: Once you confirm a signature, the on-chain transaction is irreversible. Even if the phishing is discovered later, the funds cannot be recovered.
"Structured code is still code": EIP-712 structures the signing content, but structured does not mean human-readable. What users truly need is translated action language, not tidied-up parameter fields.
eth_sign is one of the most dangerous signing methods: eth_sign can be used to sign any type of message, including transactions and contract instructions, making it the most easily exploited signing method in phishing.
How to confirm the operation is complete
Before confirming a signature, check the wallet prompt—if you see warnings like "eth_sign," "blind signing," or "cannot decode transaction," pause signing.
If your wallet supports clear signing (such as Ledger's Clear Signing or a wallet supporting ERC-7730), make sure the transaction summary shown on the screen exactly matches your intended action. If the summary is unclear or does not match your expectation, press "Reject."
After signing, check the transaction details on a blockchain explorer and verify that the executed content matches your expectation. If it does not, immediately check and revoke any potential malicious approvals using tools like Revoke.cash.
