Standard EVM Precompiles

OXN implements the standard Ethereum precompile set at addresses 0x01 through 0x09. 0x0a (KZG point evaluation, introduced with EIP-4844) is not supported — OXN does not have blob transactions.

Support matrix

Address	Name	Purpose	OXN	Gas base	Gas per word
0x01	ecrecover	Recover Ethereum signer from signature	✅	3000	—
0x02	sha256	SHA-256 hash	✅	60	12
0x03	ripemd160	RIPEMD-160 hash	✅	600	120
0x04	identity	Copy input to output	✅	15	3
0x05	modexp	Modular exponentiation (EIP-198)	✅	Complex	—
0x06	ecAdd	Elliptic curve addition on bn128 (alt_bn128)	✅	150	—
0x07	ecMul	Elliptic curve scalar multiplication on bn128	✅	6000	—
0x08	ecPairing	Pairing check on bn128	✅	45000	34000/pair
0x09	blake2f	BLAKE2b F compression function	✅	Complex	—
0x0a	pointEvaluation	KZG point evaluation (EIP-4844)	❌	—	—

Gas costs are per the current EVM specification.

Usage examples

ecrecover

Recover the Ethereum address from a signed hash:

function recoverSigner(bytes32 hash, uint8 v, bytes32 r, bytes32 s)
    external pure returns (address)
{
    return ecrecover(hash, v, r, s);
}

Used for meta-transactions, EIP-712 typed signatures, and off-chain signature verification.

sha256 / ripemd160

Cryptographic hashes:

bytes memory input = "hello";
bytes32 shaResult = sha256(input);
bytes20 ripemdResult = ripemd160(input);

keccak256 (address 0x00, not a precompile) is the standard Ethereum hash — use it unless you specifically need SHA-256 or RIPEMD-160 for compatibility with an external system.

modexp

Modular exponentiation for large numbers — used in RSA verification and other cryptographic protocols:

function modexp(bytes memory base, bytes memory exp, bytes memory mod)
    internal view returns (bytes memory)
{
    (bool success, bytes memory result) = address(0x05).staticcall(
        abi.encodePacked(base.length, exp.length, mod.length, base, exp, mod)
    );
    require(success);
    return result;
}

bn128 curve operations

Used for zkSNARK verification (Groth16, Plonk) and other pairing-based cryptography:

// ecAdd: (x1, y1) + (x2, y2) on bn128
function ecAdd(uint256 x1, uint256 y1, uint256 x2, uint256 y2)
    internal view returns (uint256, uint256)
{
    (bool success, bytes memory result) = address(0x06).staticcall(
        abi.encode(x1, y1, x2, y2)
    );
    require(success);
    return abi.decode(result, (uint256, uint256));
}

What's not supported and why

0x0a (pointEvaluation) — introduced by EIP-4844 for blob transaction verification. OXN does not have blob transactions, so this precompile has no purpose here.

If your contract needs to verify KZG commitments for reasons unrelated to blobs, you'll need to implement the verification in Solidity (expensive) or wait for a runtime upgrade to add this precompile.

Next steps

• Precompiles Overview — OXN-specific precompiles
• EVM Compatibility — opcode support matrix