미리 컴파일된 컨트랙트
Klaytn provides several useful precompiled contracts. These contracts are implemented in the platform itself as a native implementation. 미리 컴파일된 컨트랙트 중 주소 0x01부터 0x08까지의 컨트랙트는 이더리움에서 구현된 것과 동일합니다. 여기에 추가로 Klaytn은 이더리움에 없는 새로운 기능을 지원하기 위해 주소 0x09부터 0x0B까지의 미리 컴파일된 컨트랙트를 제공합니다.
NOTE: Three precompiled contract addresses have been changed, and blake2F was added after the IstanbulEVM
protocol upgrade, or the "hard fork".
IstanbulEVM
protocol upgrade block number is as follows.
Baobab Testnet:
#75373312
Cypress Mainnet:
#86816005
Contracts deployed before the protocol upgrade should use the original addresses.
case 1) The contracts deployed in Baobab at block number
#75373310
recognizes 0x09, 0x0a, and 0x0b as addresses of vmLog, feePayer, and validateSender, respectively, and blake2f cannot be used.case 2) The contracts deployed in Baobab at block number
#75373314
recognizes 0x09 as the address of blake2f, and recognizes 0x3fd, 0x3fe, and 0xff as addresses of vmLog, feePayer, and validateSender.
If you want the previous document, please refer to previous document.
Address 0x01: ecrecover(hash, v, r, s)
The address 0x01 implements ecrecover. It returns the address from the given signature by calculating a recovery function of ECDSA. Its function prototype is as follows:
Address 0x02: sha256(data)
The address 0x02 implements SHA256 hash. It returns a SHA256 hash from the given data. Its function prototype is as follows:
Address 0x03: ripemd160(data)
The address 0x03 implements RIPEMD160 hash. It returns a RIPEMD160 hash from the given data. Its function prototype is as follows:
Address 0x04: datacopy(data)
The address 0x04 implements datacopy (i.e., identity function). It returns the input data directly without any modification. This precompiled contract is not supported by the Solidity compiler. The following code with inline assembly can be used to call this precompiled contract.
Address 0x05: bigModExp(base, exp, mod)
The address 0x05 implements the formula base**exp % mod
. It returns the result from the given data. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract. Note that although this precompiled contract supports an arbitrary length of inputs, the below code uses a fixed length of inputs as an example.
Address 0x06: bn256Add(ax, ay, bx, by)
The address 0x06 implements a native elliptic curve point addition. It returns an elliptic curve point representing (ax, ay) + (bx, by)
such that (ax, ay) and (bx, by) are valid points on the curve bn256. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
Address 0x07: bn256ScalarMul(x, y, scalar)
The address 0x07 implements a native elliptic curve multiplication with a scalar value. It returns an elliptic curve point representing scalar * (x, y)
such that (x, y) is a valid curve point on the curve bn256. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
Address 0x08: bn256Pairing(a1, b1, a2, b2, a3, b3, ..., ak, bk)
The address 0x08 implements elliptic curve paring operation to perform zkSNARK verification. For more information, see EIP-197. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
Address 0x09: blake2F(rounds, h, m, t, f)
The address 0x09 implements BLAKE2b F compression function. For more information, see EIP-152. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
0x3fd 주소: vmLog(str)
The address 0x3FD prints the specified string str
to a specific file or passes it to the logger module. For more information, see debug_setVMLogTarget. Note that this precompiled contract should be used only for debugging purposes, and it is required to enable the --vmlog
option when the Klaytn node starts. Also, the log level of the Klaytn node should be 4 or more to see the output of vmLog. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
0x3fe 주소: feePayer()
The address 0x3FE returns a fee payer of the executing transaction. This precompiled contract is not supported by the Solidity compiler. The following code can be used to call this precompiled contract.
0x3ff 주소: validateSender()
The address 0x3FF validates the sender's signature with the message. Since Klaytn decouples key pairs from addresses, it is required to validate that a signature is properly signed by the corresponding sender. To do that, this precompiled contract receives three parameters:
The sender's address to get the public keys
The message hash that is used to generate the signature
The signatures that are signed by the sender's private keys with the given message hash
The precompiled contract validates that the given signature is properly signed by the sender's private keys. Note that Klaytn natively support multi signatures, which means there can be multiple signatures. The signature must be 65 bytes long.
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