ERC-1271 Signature Validation Tool

WHAT IT DOES

The ERC-1271 Signature Validation Tool enables you to verify signatures from smart contract accounts that implement the ERC-1271 standard. You specify the contract address, the hash that was signed, and the signature bytes. The tool calls the contract's isValidSignature() function and checks if the return value matches the ERC-1271 magic value (0x1626ba7e). This provides a reliable way to validate signatures from smart wallets, multisig contracts, and other contract-based signers. The tool is read-only and does not execute any transactions.

HOW TO USE

Connect your EVM wallet and select your network. Enter the contract address that implements ERC-1271, the hash (in hex), and the signature (in hex). Click "Validate signature" to call isValidSignature on the contract. The tool will display whether the signature is valid, the return value, and the expected magic value. Results are shown immediately, providing a clear pass/fail status for the signature validation.

ONE TECHNICAL SECTION — THE REAL MECHANISM

The tool interacts with the ERC-1271 standard interface, which defines a single function: isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4 magicValue). The standard specifies that a valid signature must return the magic value 0x1626ba7e. The tool constructs a contract instance with this ABI and calls the function using a static call (view function). It then compares the returned bytes4 value against the expected magic value. If they match, the signature is considered valid. The tool also checks that the contract exists (has code) before attempting the call. This provides a simple, reliable verification mechanism for contract-based signatures.

WHAT IT CANNOT SEE

The tool cannot verify off-chain signing context or guarantee validation correctness for non-standard implementations. It does not validate the content of the hash or the signature format. It cannot detect if the contract's isValidSignature implementation is malicious or incorrectly implemented. It does not verify that the signer is the intended party or that the signature was created for the correct context. The tool also cannot validate signatures from contracts that do not follow the ERC-1271 standard.

PLEASE NOTE

This tool is EVM-only and supports Ethereum, Goerli, Sepolia, Optimism, Arbitrum, Polygon, and Base. It does not support Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, or XRP. The tool assumes the contract implements the standard ERC-1271 interface. Non-standard implementations may not be detected correctly. The magic value 0x1626ba7e is defined by the ERC-1271 standard and must be returned for valid signatures. The tool is provided free and as-is; users assume full responsibility for interpreting validation results.