libbtc – A fast, clean and small bitcoin C library

What is libbtc?

Libbtc is a very portable C library for creating and manipulating bitcoin data structures and interacting with the p2p network.

Current features

• Generating and storing private and public keys
• ECDSA secp256k1 signing and verification (through libsecp256k1 included as git subtree)
• Generate recoverable signatures (and recover pubkey from signatures)
• BIP32 hierarchical deterministic key derivation
• Transaction generation, manipulation, signing and ser-/deserialization including P2PKH, P2SH, multisig
• Address generation
• Base58check encoding
• Native implementation of SHA256, SHA512, SHA512_HMAC, RIPEMD-160 including NIST testvectors
• Native constant time AES (+256CBC) cipher implementation including NIST testvectors
• Keystore (wallet) databases (through logdb https://github.com/liblogdb/liblogdb)
• Event based bitcoin P2P client capable of connecting to multiple nodes in a single thread (requires libevent)

Advantages of libbtc?

• No dependencies in case no p2p network client is required (only dependency is libsecp256k1 added as git subtree)
• The only dependency for the p2p network client is libevent (very portable)
• optimized for MCU and low mem environments
• ~full test coverage
• mem leak free (valgrind check during CI)

The bitcointool CLI

Generate a new privatekey WIF and HEX encoded:

./bitcointool -command genkey
> privatekey WIF: KwmAqzEiP7nJbQi6ofQywSEad4j5b9BXDJvyypQDDLSvrV6wACG8
> privatekey HEX: 102f1d9d91fa1c8d816ef469e74c1153a6b453d2a991e77fe187e5514a7b18ac

Generate the public key and p2pkh address from a WIF encoded private key

/bitcointool -command pubfrompriv -p KwmAqzEiP7nJbQi6ofQywSEad4j5b9BXDJvyypQDDLSvrV6wACG8
> pubkey: 023d86ca58e2519cce1729b4d36dfe5a053ad5f4ae6f7ef9360bee4e657f7e41c9
> p2pkh address: 1N5ZkjyabcZLLHMweJrSkn3qedsPGzAx9m

Generate the P2PKH address from a hex encoded compact public key

./bitcointool -command addrfrompub -pubkey 023d86ca58e2519cce1729b4d36dfe5a053ad5f4ae6f7ef9360bee4e657f7e41c9
> p2pkh address: 1N5ZkjyabcZLLHMweJrSkn3qedsPGzAx9m

Generate new BIP32 master key

./bitcointool -command hdgenmaster
> masterkey: xprv9s21ZrQH143K3C5hLMq2Upsh8mf9Z1p5C4QuXJkiodSSihp324YnWpFfRjvP7gqocJKz4oakVwZn5cUgRYTHtNRvGqU5DU2Gn8MPM9jHvfC

Print HD node

./bitcointool -command hdprintkey -privkey xprv9s21ZrQH143K3C5hLMq2Upsh8mf9Z1p5C4QuXJkiodSSihp324YnWpFfRjvP7gqocJKz4oakVwZn5cUgRYTHtNRvGqU5DU2Gn8MPM9jHvfC
> ext key: xprv9s21ZrQH143K3C5hLMq2Upsh8mf9Z1p5C4QuXJkiodSSihp324YnWpFfRjvP7gqocJKz4oakVwZn5cUgRYTHtNRvGqU5DU2Gn8MPM9jHvfC
> depth: 0
> p2pkh address: 1Fh1zA8mD6S2LBbCqdViEGuV3oDhggX3k4
> pubkey hex: 0394a83fcfa131afc47a3fcd1d32db399a0ffa7e68844546b2df7ed9f5ebd07b09
> extended pubkey: xpub661MyMwAqRbcFgAASPN2qxpRgoVdxUXvZHLWKhALMxyRbW9BZbs34ca9H3LrdsKxdMD4o5Fc7eqDg19cRTj3V9dCCeM4R1DRn8DvUq3rMva

Derive child key (second child key at level 1 in this case)

./bitcointool -command hdderive -keypath m/1h -privkey xprv9s21ZrQH143K3C5hLMq2Upsh8mf9Z1p5C4QuXJkiodSSihp324YnWpFfRjvP7gqocJKz4oakVwZn5cUgRYTHtNRvGqU5DU2Gn8MPM9jHvfC
> ext key: xprv9v5qiRbzrbhUzAVBdtfqi1tQx5tiRJ2jpNtAw8bRec8sTivLw55H85SoRTizNdx2JSVL4sNxmjvseASZkwpUopby3iGiJWnVH3Wjg2GkjrD
> depth: 1
> p2pkh address: 1DFBGZdcADGTcWwDEgf15RGPqnjmW2gokC
> pubkey hex: 0203a85ec401e66a218bf1583112599ee2a1268ebc90d91b7f457c87a50f2b011b
> extended pubkey: xpub695C7w8tgyFnCeZejvCr59q9W7jCpkkbBbomjX13CwfrLXFVUcPXfsmHGiSfpYds2JuHrXAFEoikMX6725W8VgrVL5x4ojBw9QFAPgtdw1G

The bitcoin-send-tx CLI

This tools can be used to broadcast a raw transaction to peers retrived from a dns seed or specified by ip/port. The application will try to connect to max 6 peers, send the transaction two two of them and listens on the remaining ones if the transaction has been relayed back.

Send a raw transaction to random peers on mainnet

./bitcoin-send-tx <txhex>

Send a raw transaction to random peers on testnet and show debug infos

./bitcoin-send-tx -d -t <txhex>

Send a raw transaction to specific peers on mainnet and show debug infos use a timeout of 5s

./bitcoin-send-tx -d -s 5 -i 192.168.1.110:8333,127.0.0.1:8333 <txhex>

How to Build

Full library including CLI tool and wallet database

./autogen.sh
./configure
make check

Pure library without wallet support

./autogen.sh
./configure --disable-wallet --disable-tools
make check