Introduction

Overview

Bitcoin4J is a Bitcoin library for the Java Language licensed under the Apache License 2.0.

This library has been built in line with the ideals espoused by BitcoinSV, i.e. massive on-chain scaling, protocol stability and original-bitcoin-protocol implementation.

Learn More about BitcoinSV

You can learn more about BitcoinSV by visiting :

• TwoStack Bitcoin Developer Guide
• TwoStack Youtube Channel
• Bitcoin Association Website
• BitcoinSV Wiki.

Installation

Binaries for the library are available on Maven Central.

Gradle Dependencies

implementation("org.twostack:bitcoin4j:1.6.6")

Maven Dependencies

<dependency>
  <groupId>org.twostack</groupId>
  <artifactId>bitcoin4j</artifactId>
  <version>1.6.6</version>
</dependency>

Clean Transaction Builder

Several helper classes and APIs exist to make constructing Transactions more intuitive.

See the full example source code

As a native Java implementation, the library integrates well with other JVM languages, e.g. Kotlin.

    val txBuilder: TransactionBuilder = TransactionBuilder()
    val spendingTx: Transaction = txBuilder.spendFromTransaction(aliceFundingTx, 1, Transaction.NLOCKTIME_MAX_VALUE, unlockBuilder)
        .spendTo(bobLockingBuilder, BigInteger.valueOf(10000))
        .sendChangeTo(aliceAddress, aliceLockingBuilder)
        .withFeePerKb(512)
        .build(true)

Features

• Unbounded Transaction Types (creating non-standard transactions)
• HD Key Derivation (BIP32)
• Mnemonic Seed Support (BIP39)
• Original Bitcoin Address format
• A built-in Bitcoin Script Interpreter
• Custom-Script Builder Interface to support novel locking/spending conditions within Script
  • P2PKH Transaction Builder - Pay to Pubkey Hash standard Transactions
  • P2MS Transaction Builder - Pay to Multisig. This is naked MultiSig (the proper way to do multisig).
  • P2PK Transaction Builder - Pay to Public Key standard Transactions
  • P2SH Transaction Builder - Pay to Script Hash. This should be considered deprecated. BitcoinSV Nodes support this for backwards compatibility only.
  • P2PKHDataLockBuilder - This is something new. Create a spendable data output. Spendable using P2PKH Transaction.
  • UnspendableDataLockBuilder - OP_RETURN-style Data builder. Prepends a Transaction Output Script with OP_FALSE OP_RETURN followed by a series of data pushes.

Deprecated Features

The following features represent forks away from the original Bitcoin Protocol.

This library lacks, and does not implement :

• Segregated Witness (Segwit) Transaction support (Bitcoin Core - BTC)
• Schnorr Transaction Signature support (Bitcoin Cash - BCH)
• Check Datasig (OP_CHECKDATASIG) (Bitcoin Cash - BCH)
• Taproot (Bitcoin Core - BTC)

Acknowledgement

This library is a fork of the BitcoinJ and BitcoinJ-Cash projects. Contributor acknowledgements have been preserved in the AUTHORS file.

Contact

You can reach the author at : stephan@twostack.org