End of the Year Update

Last year the development of Swift Bitcoin really kicked off. All research work done on the swift-bitcoin-poc repo was carefully moved over and improved. This includes the transaction model and script engine with full segwit and taproot support.

Other important milestones were reached. All consensus BIPs involving transactions are now implemented and tested using vectors from the specs.

Data-driven tests from Bitcoin Core covering valid/invalid transactions were ported in their totality. After considerable bug fixing and filling in blanks these tests ended up passing. The same goes for a substantial portion of taproot transaction tests.

Porting Core's tests over meant enacting all different verification flags used for configuring the script interpreter to the point of full parity.

More recently wallet functionality was added with support for encoding/decoding all types of addresses. Relevant BIPs were implemented, namely BIP32 and BIP39.

The project grew from a simple library to a package containing several integration points. Cryptography and helper functions now live in their own module while executable targets were added for utility functions and peer-to-peer "full" node functionality.

All functions calling libsecp256k1 were rewritten in pure Swift leveraging C-language interoperability.

A big effort was made to instate RPC and P2P client/server capabilities. Thanks to SwiftNIO it was possible to do this in an optimized and robust way, setting the basis for a full-blown transport layer.

This year's milestones are centered around implementing all block and transport-related BIPs. Internally a mempool, a blockchain and a chainstate will need to be created first in memory then efficiently on-disk.

Externally the goal is to get Swift Bitcoin talking to other network clients sharing blocks and transactions. Here hoping to get there before October 31st!