bitcoin-da

This package provides a reader / writer interface to bitcoin.

Example

// ExampleRelayer_Read tests that reading data from the blockchain works as
// expected.
func ExampleRelayer_Read() {
    // Example usage
    relayer, err := bitcoinda.NewRelayer(bitcoinda.Config{
        Host:         "localhost:18332",
        User:         "rpcuser",
        Pass:         "rpcpass",
        HTTPPostMode: true,
        DisableTLS:   true,
    })
    if err != nil {
        fmt.Println(err)
        return
    }
    _, err = relayer.Write([]byte("rollkit-btc: gm"))
    if err != nil {
        fmt.Println(err)
        return
    }
    // TODO: either mock or generate block
    // We're assuming the prev tx was mined at height 146
    height := uint64(146)
    blobs, err := relayer.Read(height)
    if err != nil {
        fmt.Println(err)
        return
    }
    for _, blob := range blobs {
        got, err := hex.DecodeString(fmt.Sprintf("%x", blob))
        if err != nil {
            fmt.Println(err)
            return
        }
        fmt.Println(string(got))
    }
    // Output: rollkit-btc: gm
}

Tests

Running the tests requires a local regtest node.

bitcoind -chain=regtest -rpcport=18332 -rpcuser=rpcuser -rpcpassword=rpcpass -fallbackfee=0.000001 -txindex=1

bitcoin-cli -regtest -rpcport=18332 -rpcuser=rpcuser -rpcpassword=rpcpass createwallet w1

export COINBASE=$(bitcoin-cli -regtest -rpcport=18332 -rpcuser=rpcuser -rpcpassword=rpcpass getnewaddress)

bitcoin-cli -regtest -rpcport=18332 -rpcuser=rpcuser -rpcpassword=rpcpass generatetoaddress 101 $COINBASE

Idle for a while till coinbase coins mature.

=== RUN   ExampleRelayer_Write
--- PASS: ExampleRelayer_Write (0.13s)
=== RUN   ExampleRelayer_Read
--- PASS: ExampleRelayer_Read (0.10s)
PASS
ok      github.com/rollkit/bitcoin-da   0.375s

Writer

A commit transaction containing a taproot with one leaf script

OP_FALSE
OP_IF
  "roll" marker
  <embedded data>
OP_ENDIF
<pubkey>
OP_CHECKSIG

is used to create a new bech32m address and is sent an output.

A reveal transaction then posts the embedded data on chain and spends the commit output.

Reader

The address of the reveal transaction is implicity used as a namespace.

Clients may call listunspent on the reveal transaction address to get a list of transactions and read the embedded data from the first witness input.

Spec

For more details, read the spec