This is an article in a series on Cryptography for the Everyday Developer. Follow along to learn the basics of modern cryptography and encryption. Last time we explored the Data Encryption Standard (DES), and how its Feistel network structure worked. We also saw why DES eventually became obsolete: its 56-bit key size was simply too small in the face of modern computing power. To replace DES, the U.S. National Institute of Standards and Technology (NIST) held a public competition in the late 1...