Prerequisite: Minimum grade of C- in CMSC216 and CMSC250; and permission of CMNS-Computer Science department. Covers basic topics in cryptography and explains how those topics are applied to modern forms of communication. We will cover messaging protocols and modern texting apps such as iMessage, Whatsapp, Signal, and more. We will also discuss ways of communicating with other forms of media such as audio and video. Finally, time-permitting, we will discuss the basics of quantum cryptography, and where current research in that field is headed.