zkfold-bitcoin-lib

zkfold-bitcoin-lib is a library focused on interaction with Bitcoin blockchain, such as querying Bitcoin ledger, building transactions and submitting them. It extends haskoin-core for easy transaction building.

Library defines following monadic typeclasses, their usage is illustrated in ZkFold.Bitcoin.Test.RegTest module:

• BitcoinQueryMonad: Abstracts over ledger queries, such as UTxOs at an address and submitting a transaction. Use runBitcoinQueryMonadIO to interact with it.

  Example code:

  -- Returns the block hash of genesis block.
  -- `bitcoinProvider` here is of type `BitcoinProvider`.
  runBitcoinQueryMonadIO bitcoinProvider $ blockHash 0

• BitcoinBuilderMonad: Allows building for transaction from TxSkeleton. Use runBitcoinBuilderMonadIO to interact with it.

• BitcoinSignerMonad: Allows signing of built transactions, though only for inputs locked under P2PKH, P2WPKH or a multi-sig (PayMulSig type in Haskoin). Use runBitcoinSignerMonadIO to interact with it. For complex scripts, see ZkFold.Bitcoin.Test.RegTest module for an end-to-end example.

We currently have support for raw bitcoin node (which can be ran in pruned mode, costing little of system's resources) and mempool.space.

Note that all methods provided under BitcoinQueryMonad are efficient for all the supported providers with following exceptions:

• utxosAtAddress is not efficient for locally ran bitcoin node.

RegTest testing machinery

We support convenient transaction building to tests against private (regression) testnet. First we need to set it up by running ./scripts/regtest.sh after which we can interact with it as in ZkFold.Bitcoin.Test.RegTest module (cabal run zkfold-bitcoin-lib-test).

This test setup provides a wallet (identified by testWalletAddress in ZkFold.Bitcoin.Test.Constants) with 50 BTC initially and a block is minted every 10 seconds.

Note that we can exit test setup by entering "Ctrl+C" against terminal that ran ./scripts/regtest.sh.