Papers/Books on how bitcoin works from a mathematical perspective? I'm a math student interested in Cryptography. Is there any paper or book which explains, in mathematics and cryptography terms, how bitcoin (more general, a digital cryptocurrency system) works? In my course book there is only about 4 pages on how cryptocurrencies work, but I'm hungry for more.
www.springer.com catalog is worth checking out - technical and well respected.

Andreas Antonopolous has a book out from O'Reilly (it is also available on github).

https://bitcoin.org/en/resources - check out the Developer Guide here, it's great.

Your school library will probably have loads of journals or access to them online (eg IEEE or local equiv).

Satoshi's original whitepaper is very readable: https://bitcoin.org/bitcoin.pdf

The bitcoin wiki.