Let's say I wanted to write an implementation of ECDSA from scratch to better understand it. I can't find a raw, non-abstract explanation anywhere. I tried tracking down the sources on the wiki article and going through some posts and explanations on here, but I can't find anything of substance. Where do I find basic information on this?
If you have access to IEEE Xplore or any other digital libraries that hold technical papers, I would say that is your best bet, as they usually explain concepts or implementations mathematically and algorithmically. If not, I found somebody's thesis online as a start, maybe he cites potential free resources available in the bibliography.