Karel Bílek
Software Engineer at CDN77
Prague, Prague, Czechia
Summary
🤩
Rockstar🎓
Top SchoolKarel Bílek is a pragmatic software engineer with 14 years of experience building back-end systems, embedded firmware, and front-end integrations across cryptography and high-performance delivery stacks. Currently at CDN77, he focuses on ultra-fast HTTP content delivery, while his prior roles include technical leadership in Open Banking and production Go services. He has deep hands-on experience across the Bitcoin and hardware-wallet ecosystem—contributing to Trezor, bitcoinjs-lib and Bitcoin Core sites—and has implemented USB transitions from HID to WebUSB/WinUSB. His open-source work spans machine translation, Flow type definitions, and crypto libraries, showing a rare blend of language/algorithms and low-level device expertise. Known for pragmatic debugging and system integration, he often bridges the gap between device drivers and user-facing applications. Based in Prague, he holds an MS in Computational Linguistics and brings both academic rigor and production-hardened engineering to complex systems.
14 years of coding experience
13 years of employment as a software developer
Master of Science - MS, Computational linguistics, Master of Science - MS, Computational linguistics at Charles University in Prague
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (72)
dependency-management10
flow-control10
python10
hidapi10
bitcoins10
c1110
perl10
type-definition10
c1710
type-system10
build-automation10
embedded10
bootloader10
machine-translation10
javascript10
Programming languages (28)
Github contributions (5)
trezor/trezord-go
Jan 2018 - Mar 2019
:smiling_imp: Trezor Communication Daemon (written in Go)
Role in this project:
Backend Developer
Backend DeveloperContributions:1 release, 332 commits, 112 PRs in 1 year 2 months
Contributions summary:Karel's commits primarily involve replacing external dependencies (libusb and hidapi) within the Trezor Communication Daemon. They refactored existing code, replacing the old libraries with newer implementations. These changes were implemented across multiple files within the project, showcasing a focus on maintaining and updating core dependencies of the daemon. The user also updated the project's windows build process.
golangdaemoncommunicationtrezorimp
trezor/trezor-crypto
Jan 2016 - Jun 2018
:lock: Don't use this repo, use the new monorepo instead:
Role in this project:Back-end Developer
Back-end DeveloperContributions:14 commits, 8 PRs, 23 pushes in 2 years 5 months
Contributions summary:Karel contributed to the `trezor-crypto` repository by implementing and testing cryptographic functions. Their work included adding segwit test vectors, which are essential for validating Bitcoin transaction formats. Additionally, the user built and integrated Emscripten compiled outputs, which are likely used to enable the functionality of the trezor-crypto library in web browsers. Furthermore, the user worked on the Overwinter Zcash hashing algorithm.
lockx25519ecdhsignature-verificationelliptic-curve-cryptography
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