> For the complete documentation index, see [llms.txt](https://docs.fringe.fi/smart-contract-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fringe.fi/smart-contract-documentation/openzeppelin/contracts-upgradeable/utils/cryptography/signaturecheckerupgradeable.md).

# Signature Checker Upgradeable

*Signature verification helper: Provide a single mechanism to verify both private-key (EOA) ECDSA signature and ERC1271 contract sigantures. Using this instead of ECDSA.recover in your contract will make them compatible with smart contract wallets such as Argent and Gnosis. Note: unlike ECDSA signatures, contract signature's are revocable, and the outcome of this function can thus change through time. It could return true at block N and false at block N+1 (or the opposite). Available since v4.1.*