Simple Technical Guide for RGB++ Development

rgbpp-simple-guilde.md

Simple Technical Guide for RGB++ Development

RGB++ Code Examples

• Find code examples at https://github.com/ckb-cell/rgbpp-sdk/tree/develop/examples/rgbpp

Components

• CKB Scripts (Contracts)

  • CKB Bitcoin SPV Type Script: A type script for Bitcoin SPV clients which synchronize Bitcoin state into CKB

  • RgbppLockScript and BtcTimeLockScript

    • design: https://github.com/ckb-cell/RGBPlusPlus-design/blob/main/docs/light-paper-en.md
    • testnet: https://pudge.explorer.nervos.org/scripts#RGB++
    • mainnet: https://explorer.nervos.org/scripts#RGB++

• The RGB++ SDK repository offers utilities for Bitcoin and RGB++ asset integration:

  • @rgbpp-sdk/btc: Bitcoin part of the SDK
  • @rgbpp-sdk/ckb: Nervos CKB part of the SDK
  • @rgbpp-sdk/service: Wrapped interfaces of Bitcoin/RGB++ Assets Service

• Bitcoin/RGB++ Assets Service offers various features for interacting with Bitcoin and RGB++ assets:

  • Retrieve Blockchain Information including Bitcoin chain info, blocks, headers, transactions, addresses, and RGB++ assets
  • Handle transactions by posting to /bitcoin/v1/transaction or /rgbpp/v1/transaction/ckb-tx
  • Generate Bitcoin transaction Proof via /rgbpp/v1/btc-spv/proof through Bitcoin SPV Service on CKB
  • Simplify RGB++ assets workflows with RGB++ CKB transaction Queue and cron jobs
  • More detailed API documentation can be found on Testnet and Mainnet

RGB++ Asset Workflow Overview

1. Creation of rgbpp_ckb_tx_virtual using @rgbpp-sdk/ckb

   1. BTC → BTC
   2. BTC → CKB
   3. CKB → BTC (isomorphic rgbpp_btc_tx is not required in this workflow)

Important

It's recommended to store the rgbpp_ckb_tx_virtual locally in case you need it in the future.

2. Creation of rgbpp_btc_tx through @rgbpp-sdk/btc

   1. construct isomorphic rgbpp_btc_tx based on rgbpp_ckb_tx_virtual and rgbpp commitment
   2. sign and broadcast rgbpp_btc_tx to obtain rgbpp_btc_txid

3. JoyID or dApp sends rgbpp_btc_txid and rgbpp_ckb_tx_virtual to RGB++ CKB transaction Queue (API Endpoint: /rgbpp/v1/transaction/ckb-tx)

4. RGB++ CKB transaction Queue will process the following things:

   1. verify the received requests
   2. continuously fetch request from the queue through a cron job
   3. check whether the confirmations of req.rgbpp_btc_txid is sufficient
   4. generate the witnesses for RgbppLocks in the rgbpp_ckb_tx_virtual
   5. add a paymaster cell into rgbpp_ckb_tx_virtual.inputs if the CKB capacity is insufficient
      1. need to verify the existence of paymaster UTXO in the rgbpp_btc_tx
      2. sign the paymaster cell and the entire transaction if needed
   6. finalize the rgbpp_ckb_tx_virtual to a rgbpp_ckb_tx
   7. broadcast rgbpp_ckb_tx and mark the job as completed upon tx-confirmation

Notes

• The RGB++ CKB transaction Queue is designed to streamline the transaction workflow. Developers have the option to implement its features by themselves without limitation.

Another Cron Job

• btc_time_lock → target_ckb_address automation for the BTC → CKB workflow
  • every 10 minutes, a cron job queries mature btc_time_lock cells, which means the related btc_txid in btc_time_lock.args has 6+ confirmations
  • construct a transaction converting the mature btc_time_lock cells to the target_ckb_addresses