I forgot to mention "Cryptonomicon" by Neal Stephenson, when I recommended "Quiksilver". Stephenson gets some divided reviews for his style and endings, but his books are usually thoughtful, full of math/sci-comp esoterica, alternate history etc.

"Cryptonomicon" is a fun pseudo-historical fiction with a lot of math and cryptography throughout -- it takes place in the 1990s and WWII era, moving between the two often. Has lots of stuff about WWII cryptography, also the 1990s stuff is very cypherpunk. It is, I think one of the earliest (idk if it has precursors), examples of cryptocurrency and freedom / humanistic movements figuring in the plot.