I have been hacking Linux since 1994 and programming C/assembly (also some C++ and Go) since then.
Git, make and related build tools, gcc, llvm, performance analyzing and optimizing with assembly/perf/valgrind.
Network/communications/operational security, (secure) programming and testing, cryptography, cryptocurrencies, Linux systems administration, VPS services, Amazon S3 etc.
I follow trends in security and vulnerabilities in software/hardware/people.
I do freelance coding projects, code reviews, etc, use contact methods listed below.