The popular symmetric encryption algorithms in use today have a lot more in common, on a conceptual level, than they have differences between them. A certain set of basic operations and frameworks are known to stand on solid mathematical ground and have withstood years of cryptanalysis. As such, all the general remarks of this section apply almost equally well to any symmetric algorithm you might find yourself working with. Specific details can be found in the documentation associated with a specific algorithm.

Using the right basic operations and frameworks does not guarantee a strong algorithm. There are many subtle ways to put things together that introduce significant vulnerabilities to attack. Understanding this tutorial is not enough to allow you to invent your own strong algorithm; however, "rolling your own" is not a useful goal for most programmers anyway. There are so many well-tested algorithms out there that you are almost surely better off starting with them and worrying only about implementation. This tutorial will allow you to understand the logic behind what you are implementing.