It depends on what field you're interested in. Science doesn't matter much in most fields in computer science tbh, though maths can. Encryption is mostly covered in cryptography, but I assume you want to learn about internet and networking?
Computer Networking A top down approach by Kurose Ross is good one. Also you can try Computer Networks and Internets by Douglas Comer and Narayanan. There are good videos on youtube about it. It depends on what specifically interests you.
Network Security: Private Communications in a Public World by Perlman & Kaufman. It is a network security book with more focus on cryptography and cryptographic protocols. It has a lot of practical stuff and a run down of the common protocols used. It's good for beginners, even if you haven't read much about networks
Network Security 2nd Ed - Kaufman, Perlman, et al.
It covers modern cryptography and network security protocols and is easy to read. My favourite book if you're looking to learn about the field.
There are some pretty neat courses on coursera for security, not sure if there are network security specific ones. I know Stanford offers some free security classes once in a while.
In terms of books, I think my netsec course used this one - http://www.amazon.com/Network-Security-Private-Communication-Edition/dp/0130460192. (which is pretty outdated but the basics are the same).
Here is the amazon link for the actual book:
Network Security: Private Communication in a Public World (2nd Edition) https://www.amazon.com/dp/0130460192/ref=cm_sw_r_cp_apa_i_Qp1kEbQ8D6ZJ7
Please check and let me know.