I simplified the code, see the github repository. No extra functions and no macro needed anymore for the Sha256 and Ripemd160 hash, 20 lines shorter and easier to read now.

I think Rust is a good choice for writing blockchain related code. Typesafe and fast like C++, but the Rust compiler is much better. Together with the borrowing memory concept it is really hard to write code which crashes, or has memory leaks or undefined behavior at runtime, which is no problem at all with C++. And there are over 70,000 Rust crates (what other languages call modules or libraries) available for nearly everything you can imagine, usable with one line in the cargo.toml file with the nice "cargo" build system.