Libbitcoin slides

1. libbitcoin

2. Typical Bitcoin Company Application Centralized API Provider Gem, Chain, Blockchain.info, Coinbase, BlockCypher, ... Shopping, Escrow, Smart contracts, Tipping, etc...

3. libbitcoin is a Blockchain API Application libbitcoin- server Open Source, Decentralized Shopping, Escrow, Smart contracts, Tipping, etc...

4. libbitcoin is a Power-user CLI Tool libbitcoin- explorer (BX) libbitcoin- server Scripting, Research, Exploration, ... $ bx fetch-height 345896

5. libbitcoin is a Blockchain Toolkit libbitcoin libbitcoin-blockchain libbitcoin-client libbitcoin-node libbitcoin-server libbitcoin-explorer Server Stack Client Stack

6. Why does this matter? ● Right now, most of the network runs a single piece of software (the Satoshi node) ● The Bitcoin Foundation controls this software ● Monocultures are bad! ● libbitcoin is a complete third-party Bitcoin Blockchain implementation

7. libbitcoin Users ● DarkWallet ● OpenBazaar ● AirBitz

8. libbitcoin Tour libbitcoin libbitcoin-blockchain libbitcoin-client libbitcoin-node libbitcoin-server libbitcoin-explorer Server Stack Client Stack

9. libbitcoin ● Modern C++11 codebase. ● Designed as a collection of simple, decoupled classes ● You can use as much or as little funtionality as you like

10. libbitcoin ● Basic blockchain types – Blocks, Transactions, Scripts, Crypto primitives, ... ● Wallet types – Base58, Addresses, URLs, HD keys, Message signing, … ● P2P Protocol

12. libbitcoin-blockchain ● High-performance blockchain database ● Custom-designed on-disk hash table ● Rich indexes for high-speed queries – Transactions – Addresses – Stealth

14. libbitcoin-server ● Formerly known as “obelisk” ● Provides a low-level Blockchain API ● Uses ZeroMQ

15. libbitcoin-server ● fetch_history ● fetch_transaction ● fetch_last_height ● fetch_block_header ● fetch_transaction_index ● fetch_stealth ● broadcast_transaction ● subscribe

17. libbitcoin-client ● C++ wrapper around the libbitcoin-server RPC interface ● Server API calls are as easy as calling a C++ function

18. darkwallet/python-obelisk ● For those who want to use libbitcoin-server from python

19. darkwallet/gateway ● Bridges libbitcoin-server to Websockets ● For those who want to use libbitcoin-server from Javascript

21. libbitcoin-explorer ● Short name is “bx” ● Replaces an earlier project called “sx” ● Command-line interface to lots of Bitcoin goodies

22. libbitcoin-explorer ● Server Commands – fetch-balance, fetch-header, fetch-height, fetch-history, fetch-public-key, fetch- stealth, fetch-tx, fetch-tx-index, fetch-utxo ● Wallet – input-set, input-sign, input-validate, message-sign, message-validate, send-tx, send-tx-node, send-tx-p2p, tx-decode, tx- encode, tx-sign

23. libbitcoin-explorer ● HD Keys – hd-new, hd-private, hd-public, hd-to-address, hd- to-ec, hd-to-public, hd-to-wif ● EC Math – ec-add, ec-add-secrets, ec-lock, ec-multiply, ec- multiply-secrets, ec-new, ec-to-address, ec-to- public, ec-to-wif, ec-unlock ● Hashes – bitcoin160, bitcoin256, sha160, sha256, sha512, ripemd160

24. libbitcoin-explorer ● Format conversions – address-decode, address-encode – base16-decode, base16-encode – base58-decode, base58-encode – base64-decode, base64-encode – btc-to-satoshi, satoshi-to-btc – wif-to-ec, wif-to-public ● And lots more…

25. Installing bx ● Available as a single-file pre-compiled binary: – https://github.com/libbitcoin/libbitcoin- explorer/wiki/Download-BX – Linux, OS X, and Windows! ● Or you can compile it yourself: – https://github.com/libbitcoin/libbitcoin-explorer – Use the install.sh script for an hands-off compile, including dependencies – Or follow the manual build instructions

26. Installing libbitcoin-server ● Stable binaries are not yet available – Hopefully soon! ● Source code is here: – https://github.com/libbitcoin/libbitcoin-server ● To run: $ initchain $ bitcoin_server

27. libbitcoin-server Servers ● https://wiki.unsystem.net/en/index.php/Obelisk/Servers ● The BX default is tcp://obelisk.airbitz.co:9091 ● Feel free to use the AirBitz servers! – If you install your own servers, please let us use them too

28. Installing libbitcoin ● Source code is here: – https://github.com/libbitcoin/libbitcoin

29. libbitcoin Example #include <bitcoin/bitcoin.hpp> #include <iostream> #include <string.h> int main() { char line[256]; std::cout << "Please enter a secret phrase: "; std::cin.getline(line, 256); bc::data_chunk seed(line, line + strlen(line)); bc::hash_digest hash = bc::sha256_hash(seed); std::cout << "Hash: " << bc::encode_base16(hash) << std::endl; std::cout << "Private key: " << bc::secret_to_wif(hash) << std::endl; bc::payment_address address; bc::set_public_key_hash(address, bc::bitcoin_short_hash(bc::secret_to_public_key(hash))); std::cout << "Address: " << address.encoded() << std::endl; return 0; }

30. libbitcoin Example - Header #include <bitcoin/bitcoin.hpp>

31. libbitcoin Example – Grab some text char line[256]; std::cout << "Please enter a secret phrase: "; std::cin.getline(line, 256); bc::data_chunk seed(line, line + strlen(line));

32. libbitcoin Example – Hashing bc::hash_digest hash = bc::sha256_hash(seed); std::cout << "Hash: " << bc::encode_base16(hash) << std::endl; std::cout << "Private key: " << bc::secret_to_wif(hash) << std::endl;

33. libbitcoin Example – Addresses bc::payment_address address; bc::set_public_key_hash(address, bc::bitcoin_short_hash( bc::secret_to_public_key(hash))); std::cout << "Address: " << address.encoded() << std::endl;

34. libbitcoin Example – Makefile CXXFLAGS = $(shell pkg-config --cflags libbitcoin) LIBS = $(shell pkg-config --libs libbitcoin) test: test.o $(CXX) -o test test.o $(LIBS) test.o: test.cpp $(CXX) -c -o test.o test.cpp $(CXXFLAGS)

35. Future Plans ● New libbitcoin-server protocol – We want a full query language – libbitcoin-protocol ● SPV client library – libitcoin-server is fast, so we don't want to lose that – The client uses block headers to verify server responses

36. Slides ● Slides are here: – http://www.slideshare.net/swansontec/libbitcoin- slides