Sourceful VS bitcoinbook

This might be a good place to start.

www.hackingwithswift.com has good free resources and also some paid. Good place to start ;)

Sometimes the documentation can feel incomplete… though sometimes there are some really helpful tutorials. Once place I’ve found good info is from WWDC. Another is from Paul Hudson on https://www.hackingwithswift.com

Check out these resources.

For example, Paul Hudson's Hacking with Swift has 100 days of Swift and 100 days of SwiftUI. The first 15 days are dedicated to basics of programming like learning about variables, dictionary, etc. maybe you can skip through those but I would still look into topics like extensions, protocols, etc.

iOS programming is really straightforward, and with the advent of Swift and SwiftUI, it is really accessible. I kicked around an idea last year, and managed to get quite a decent prototype together very quickly. It doesn't have the best documentation for the language and software development kits, but there are loads of resources on the internet (Hacking with Swift is a good place to start).

"Mastering Bitcoin" by Andreas M. Antonopoulos: The printed version is not free, the complete text is available on GitHub. It's an excellent resource for understanding Bitcoin from a technical perspective.

The target is stored in the block header. You can see it in any block explorer labeled BITS or nBits. It is stored in a compressed format, as described in Mastering Bitcoin https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch10.asciidoc Scroll down to "Target Representation"

Mastering Bitcoin is a free book - https://github.com/bitcoinbook/bitcoinbook

I also highly recommend that you Read this book "Mastering bitcoin", its free and open source: https://github.com/bitcoinbook/bitcoinbook

You should read this chapter - it kinda explains why the chip need to be able to manipulate and access the private key. It works exactly the same way for every hardware wallet.