Number: "0024"
Category: Informational
Status: Draft
Author: Dylan Duan
Organization: Nervos Foundation
Created: 2020-05-21

CKB System Script List

Abstract

System scripts are the smart contracts built and deployed by the CKB core team. System scripts complement the function of CKB in a flexible way. System scripts can provide core functions (e.g. SECP256k1/blake160 and Nervos DAO), shared standard implementations (e.g. Simple UDT) or other auxiliary infrastructure components. This document presents the information of all Nervos CKB system scripts, including a brief introduction and code_hash, hash_type, out_point(tx_hash and index), dep_type on mainnet Lina and testnet Aggron.

Motivation

System scripts are used frequently in dapps, wallets, and other application development. A list of system scripts provides a handy reference to developers.

List of System Scripts

• Locks

  • SECP256K1/blake160
  • SECP256K1/multisig
  • anyone_can_pay

• Types

  • Nervos DAO

• Standards

  • Simple UDT

To construct transactions with system scripts, the code_hash, hash_type, out_point and dep_type of system scripts in mainnet Lina and testnet Aggron are needed.

Locks

SECP256K1/blake160

SECP256K1/blake160 (Source Code) is the default lock script to verify CKB transaction signature.

SECP256K1/blake160 script is for lock script:

• Lina

Note:

The dep_type of SECP256K1/blake160 in Lina is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and secp256k1_blake160_sighash_all whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x3
}

and the out_point of secp256k1_blake160_sighash_all is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x1
}

• Aggron

Note:

The dep_type of SECP256K1/blake160 in Aggron is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and secp256k1_blake160_sighash_all whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x3
}

and the out_point of secp256k1_blake160_sighash_all is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x1
}

SECP256K1/multisig

SECP256K1/multisig (Source Code) is a script which allows a group of users to sign a single transaction.

SECP256K1/multisig script is for lock script:

• Lina

Note:

The dep_type of SECP256K1/multisig in Lina is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and secp256k1_blake160_multisig_all whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x3
}

and the out_point of secp256k1_blake160_multisig_all is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x4
}

• Aggron

Note:

The dep_type of SECP256K1/blake160 in Aggron is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and secp256k1_blake160_multisig_all whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x3
}

and the out_point of secp256k1_blake160_multisig_all is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x4
}

anyone_can_pay

anyone_can_pay (Source Code) allows a recipient to provide cell capacity in asset transfer.

anyone_can_pay script is for lock script:

• Lina

Note:

The dep_type of anyone_can_pay in Lina is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and anyone_can_pay whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x3
}

and the out_point of anyone_can_pay whose dep_type is code is

{
  tx_hash: 0x58eb58e2e3dd9852099a19424cf6e63b5238afe92e3085561b8feafced6d6876,
  index: 0x0
}

• Aggron

Note:

The dep_type of anyone_can_pay in Aggron is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and anyone_can_pay whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x3
}

and the out_point of anyone_can_pay is

{
  tx_hash: 0xce29e27734b3eb6f8b6a814cef217753ac2ccb4e4762ecc8b07d05634d8ba374,
  index: 0x0
}

cheque

cheque (Source Code) allows a sender to temporarily provide cell capacity in asset transfer.

cheque script is for lock script:

• Lina

Note:

The dep_type of cheque in Lina is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and cheque whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0xe2fb199810d49a4d8beec56718ba2593b665db9d52299a0f9e6e75416d73ff5c,
  index: 0x3
}

and the out_point of cheque whose dep_type is code is

{
  tx_hash: 0x0a34aeea122d9795e06e185746a92e88bca0ad41b0e5842a960e5fd1d43760a6,
  index: 0x0
}

• Aggron

Note:

The dep_type of cheque in Aggron is dep_group means that the content of this dep cell contains two cell deps which are secp256k1_data and cheque whose dep_type are code.

The out_point of secp256k1_data is

{
  tx_hash: 0x8f8c79eb6671709633fe6a46de93c0fedc9c1b8a6527a18d3983879542635c9f,
  index: 0x3
}

and the out_point of cheque is

{
  tx_hash: 0x1b16769dc508c8349803fe65558f49aa8cf04ca495fbead42513e69e46608b6c,
  index: 0x0
}

Types

Nervos DAO

Nervos DAO (Source Code) is the script implements Nervos DAO.

Nervos DAO script is for type script:

• Lina

• Aggron

Standards

Simple UDT

Simple UDT (Source Code) implements the minimum standard for user defined tokens on Nervos CKB.

Simple UDT script is for type script:

• Lina

• Aggron