As a certified Cryptanalyst for the National Security Agency, the speaker was classically trained in manual cryptography, but also pioneered some of the first computer-based cryptographic systems produced by the agency. Topics discussed will include applications of classic cryptography including one-time pads and various cipher methods to machine-based systems (such as the Enigma) and ultimately to modern computer-based algorithms such as public key cryptography. Understanding the history and evolution of cryptography is essential for applying modern cryptographic solutions to solve today’s information security problems, particularly in understanding the residual risks, the shifting attack strategies, and the inherent weaknesses in the implementation or fielding of even the best cryptosystems and solutions.