Read this tutorial for the long answer. The short answer is that cryptology is made up of cryptography and cryptanalysis. The first, cryptography, is the actual securing, control, and identification of digital data. The second, cryptanalysis, is made up of all the attempts one might develop to undermine, circumvent, and/or break what the first part, cryptography, is attempting to accomplish.

The focus of Part 1 of this three-part tutorial is to introduce readers to general concepts and address cryptanalysis in somewhat greater depth. Part 2 addresses cryptographic algorithms and protocols in more detail. Part 3 introduces users to a variety of protocols useful for accomplishing specific and specialized tasks.