ECDSA

Elliptic Curve Digital Signature Algorithm (ECDSA) operations. These functions can be used to verify that a message was signed by the holder of the private keys of a given address.

*Returns the address that signed a hashed message (hash) with signature or an error. This will not return address(0) without also returning an error description. Errors are documented using an enum (error type) and a bytes32 providing additional information about the error. If no error is returned, then the address can be used for verification purposes. The ecrecover EVM precompile allows for malleable (non-unique) signatures: this function rejects them by requiring the s value to be in the lower half order, and the v value to be either 27 or 28. IMPORTANT: hash must be the result of a hash operation for the verification to be secure: it is possible to craft signatures that recover to arbitrary addresses for non-hashed data. A safe way to ensure this is by receiving a hash of the original message (which may otherwise be too long), and then calling MessageHashUtils-toEthSignedMessageHash on it. Documentation for signature generation:

with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]*

function tryRecover(bytes32 hash, bytes memory signature)
    internal
    pure
    returns (address recovered, RecoverError err, bytes32 errArg);

recover

Returns the address that signed a hashed message (hash) with signature. This address can then be used for verification purposes. The ecrecover EVM precompile allows for malleable (non-unique) signatures: this function rejects them by requiring the s value to be in the lower half order, and the v value to be either 27 or 28. IMPORTANT: hash must be the result of a hash operation for the verification to be secure: it is possible to craft signatures that recover to arbitrary addresses for non-hashed data. A safe way to ensure this is by receiving a hash of the original message (which may otherwise be too long), and then calling MessageHashUtils-toEthSignedMessageHash on it.

function recover(bytes32 hash, bytes memory signature) internal pure returns (address);

tryRecover

Overload of {ECDSA-tryRecover} that receives the r and vs short-signature fields separately. See https://eips.ethereum.org/EIPS/eip-2098[ERC-2098 short signatures]

function tryRecover(bytes32 hash, bytes32 r, bytes32 vs)
    internal
    pure
    returns (address recovered, RecoverError err, bytes32 errArg);

recover

Overload of ECDSA-recover that receives the r and vs` short-signature fields separately.

function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address);

tryRecover

Overload of {ECDSA-tryRecover} that receives the v, r and s signature fields separately.

function tryRecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s)
    internal
    pure
    returns (address recovered, RecoverError err, bytes32 errArg);

recover

Overload of ECDSA-recover that receives the v, r and s signature fields separately.

function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address);

_throwError

Optionally reverts with the corresponding custom error according to the error argument provided.

function _throwError(RecoverError error, bytes32 errorArg) private pure;

Errors

ECDSAInvalidSignature

The signature derives the address(0).

error ECDSAInvalidSignature();

ECDSAInvalidSignatureLength

The signature has an invalid length.

error ECDSAInvalidSignatureLength(uint256 length);

ECDSAInvalidSignatureS

The signature has an S value that is in the upper half order.

error ECDSAInvalidSignatureS(bytes32 s);

Enums

RecoverError

enum RecoverError {
    NoError,
    InvalidSignature,
    InvalidSignatureLength,
    InvalidSignatureS
}

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