Crypto Syscalls

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Signature Syscalls

Crypto syscalls verify signatures against the current transaction's script container.

Syscall Name	Gas Cost	Description	Devpack Wrapper
System.Crypto.CheckSig	1,000	Verify single signature	Syscalls.checkSig(pubkey, sig)
System.Crypto.CheckMultisig	1,000	Verify multiple signatures	Syscalls.checkMultisig(pubkeys, sigs)

These syscalls verify signatures against the hash of the current script container (transaction). For general-purpose signature verification with arbitrary messages, use the CryptoLib native contract via Syscalls.verifyWithECDsa().

Example Usage

import "devpack/contracts/Syscalls.sol";

contract Verifier {
    // Verify a single signature against the current transaction
    function verifySigner(bytes memory publicKey, bytes memory signature)
        external view returns (bool)
    {
        return Syscalls.checkSig(publicKey, signature);
    }

    // For arbitrary message verification, use CryptoLib (native contract)
    function verifyMessage(
        bytes32 messageHash,
        bytes memory publicKey,
        bytes memory signature
    ) external view returns (bool) {
        return Syscalls.verifyWithECDsa(
            messageHash, publicKey, signature,
            Syscalls.SECP256K1_SHA256  // or SECP256R1_SHA256
        );
    }
}

Native CryptoLib

INFO

Most cryptographic operations in Neo N3 are handled by the CryptoLib native contract (SHA256, RIPEMD160, keccak256, ECDSA, Ed25519, BLS12-381, Murmur32), which is invoked via System.Contract.Call rather than dedicated syscalls. The two System.Crypto.* syscalls exist specifically for transaction-level signature verification used in consensus and verification triggers.