This is a simple Kotlin Multiplatform library which implements most of the bitcoin protocol:

• base58 encoding/decoding
• block headers, block and tx parsing
• tx creation, signature and verification
• script parsing and execution (including OP_CLTV and OP_CSV)
• pay to public key tx
• pay to script tx / multisig tx
• BIP 32 (deterministic wallets)
• BIP 39 (mnemonic code for generating deterministic keys)
• BIP 86 (key derivation for p2tr outputs)
• BIP 173 (Base32 address format for native v0-16 witness outputs)
• BIP 174 (Partially Signed Bitcoin Transaction Format v0)
• BIP 341 and 342 (taproot and tapscript transactions)
• BIP 350 (Bech32m format)

Our goal is not to re-implement a full Bitcoin node but to build a library that implements all the primitives that you need to create bitcoin applications: building and signing transactions, verifying transactions, working with custom bitcoin scripts, parsing blocks, headers, transactions, building BIP39 wallets...

And of course we use this library in our new multiplaform lightning engine https://github.com/ACINQ/lightning-kmp.

Our runtime targets are:

• JVM
• Android
• iOS
• Linux 64 bits (for testing/prototyping only, you should use the JVM for production applications)

• [X] Message parsing (blocks, transactions, inv, ...)
• [X] Building transactions (P2PK, P2PKH, P2SH, P2WPK, P2WSH)
• [X] Signing transactions
• [X] Verifying signatures
• [X] Passing core reference tests (scripts & transactions)
• [X] Passing core reference segwit tests
• [X] Passing core reference psbt v0 tests

bitcoin-kmp is available on maven central

• Multiplatform: Add the fr.acinq.bitcoin:bitcoin-kmp dependency to your common source set dependencies (you need Gradle 5.0 minimum).
• JVM: Add the fr.acinq.bitcoin:bitcoin-kmp-jvm dependency to your project.

You need to add a JVM implementation of Secp256k1 to your project in order to use bitcoin-kmp with JVM.

Please refer the Secp256k1 installation section.

Please have a look at unit tests, more samples will be added soon.