http://www.saylor.org/majors/computer-science/

https://www.cybrary.it/

http://opensecuritytraining.info/Welcome.html

Linear algebra

Discrete mathematics

The C Programming Language Book by Brian Kernighan and Dennis Ritchie

Concrete Mathematics: Foundation for Computer Science by Ronald L. Graham, Donald E. Knuth and Oren Patashnik

Introduction to Algorithms Book by Charles E. Leiserson, Clifford Stein, Ronald Rivest, and Thomas H. Cormen

Art of Computer Programming, Volumes 1-4A Boxed Set, The By Donald E. Knuth