Modern History of Cryptography Techniques
Heather writes "The encryption scheme you rely on today might be full of holes just a few years down the road. Learn how far we've come in the last few decades, and why your apps need to be ready for change. This article builds on a previous article about Enigma, Germany's WWII-era encryption system."
TCP is not used for transmitting voice in most applications. Why would you want retransmissions during a conversation? There is no TCP stream, and therefore no "negligible-load" encryption. Do you want to ask about encryption of UDP streams now? Nice try. Come back in a few years when you actually know something about networks.