I am Sebastian, a computer engineer living in Vienna/Austria.

My GitHub activity primarily consists of contributing to Bitcoin Core in my spare-time by thoroughly reviewing PRs (conceptual reviews and code reviews), as well as opening own PRs (202 merged so far) to improve the codebase in various ways, mostly adding/improving tests and network code, refactoring, as well as clarifying the codebase and docs.

A portfolio of some of the milestone PRs throughout my first year of contributing:

• (https://github.com/bitcoin/bitcoin/pull/16753) wallet: extract PubKey from P2PK script with Solver
  That's when all the magic started -- my first ever code change contribution to Bitcoin Core!
• (https://github.com/bitcoin/bitcoin/pull/16786) test: add unit test for wallet watch-only methods involving PubKeys
  Follow-up to the previous PR that made me familiar with the unit test framework (Boost).
• (https://github.com/bitcoin/bitcoin/pull/17108) test: fix "tx-size-small" errors after default address change
  First change in the functional test framework (written in Python3) that was needed after the change to bech32 as the default address format.
• (https://github.com/bitcoin/bitcoin/pull/17183) refactor: test/bench: dedup Build{Crediting,Spending}Transaction()
  First refactoring commit, deduplicating functions by moving them into a common new transactions util library.
• (https://github.com/bitcoin/bitcoin/pull/17480) test: add unit test for non-standard txs with too large scriptSig
  The first among many added functional and unit tests to check for reject reasons of non-standard transactions. See issue https://github.com/bitcoin/bitcoin/issues/17394 which also encouraged newcomers to contribute via the "good first issue" label.
• (https://github.com/bitcoin/bitcoin/pull/18396) rpc: add missing HelpExampleRpc for getblockfilter
  First RPC documentation change of many following, primarily adding or fixing RPC examples.
• (https://github.com/bitcoin/bitcoin/pull/18426) scripts: previous_release: improve behaviour on failed download
  Also the scripts in the contrib folder need some love from time to time!
• (https://github.com/bitcoin/bitcoin/pull/18515) test: add BIP37 remote crash bug [CVE-2013-5700] test to p2p_filter.py
  Adding a regression test for CVE-2013-5700. Finding and triggering the (not too hard to spot, but undocumented) crash vulnerability was great fun!
• (https://github.com/bitcoin/bitcoin/pull/18544) net: limit BIP37 filter lifespan (active between 'filterload'..'filterclear')
  Fixing a minor bug in the BIP37 protocol implementation (see https://github.com/bitcoin/bitcoin/issues/18483)
• (https://github.com/bitcoin/bitcoin/pull/18806) net: remove is{Empty,Full} flags from CBloomFilter, clarify CVE fix
  Improved code quality of the BIP37 implementation by removing unneeded and confusing code that was introduced years ago in course of a covert fix for CVE-2013-5700. This PR was also discussed in a PR review club meeting.

Sponsorships funds will be used for making the development more efficient and pleasant (ranging from simple things as tea/coffee, food to e.g. rent for a prospering coworking space or new electrical devices for programming) and of course to give a huge motivational boost 🚀

[ First goal of having 7 sponsors has been reached on Dec. 11th 2020 🎉 👏 👌 -- thanks to all supporters! ❤️ ]

Research agenda for 2022:

• explore possibilities that come with the recently merged (but not yet activated) Schnorr signatures, Taproot and Tapscript (BIPs 340, 341, 342), e.g. MuSig2
• digging deeper into the promising CoinSwap protocol, particularly Chris Belcher's implementation in Rust (https://github.com/bitcoin-teleport/teleport-transactions)
• getting a solid understanding of the Lightning network by reading all BOLT specifications and probably also contributing to one of the clients, preferrably c-lightning (where I contributed and named a release before)