One more thing, if you're curious about taking your first step
into actually learning the basics of cryptography, you can use
this:
https://www.coursera.org/courses?search=cryptography
Dan Boneh is a well respected expert in cryptography and his
class is very well structured (it wasn't the first one I took,
but it's definitely comparable to an actual college course on
cryptography). Do not take it expecting that you'll even be
remotely capable of going against the recommendations by experts
by the end (in fact, you'll learn that such things is idiocy if
you pay any attention to it).
If you do take it, do the assignments and homework. Despite such
things having the reputation of being just a bother, the
assignments are necessary to fully understand the material for
advanced topics like this. They are tough but they'll teach you
pretty quickly that looking at, for instance, the number of bits
in crc32 is meaningless for creating attacks.
