Cryptography has a fascinating history going back thousands of years. However, until relatively recently all cryptographic algorithms fell into one category referred to as symmetric encryption. In symmetric encryption both the sender and receive share a single key that is used both to encrypt and decrypt messages. Encryption takes a plaintext message and produces a ciphertext. Decryption takes the ciphertext message and produces the originalplaintext. A variety of simple symmetric encryption algorithms exist. Symmetric encryption is still in wide use today, although computers have allowed the algorithms that are used to become significantly more complex and secure.
Credits: Talking: Geoffrey Challen (Assistant Professor, Computer Science and Engineering, University at Buffalo). Producing: Greg Bunyea (Undergraduate, Computer Science and Engineering, University at Buffalo).
Part of the www.internet-class.org online internet course. A blue Systems Research Group (blue.cse.buffalo.edu) production.