Introduction

A one-time pad is one of the best ways of making truly secret messages. Created and used correctly, it can be mathematically proven that it cannot be broken. While anyone looking at the ciphertext might easily guess it is a secret message, figuring out exactly what the cleartext says is truly impossible.

Provided with equipment, space and operating expenses by the National Security Agency (NSA), the museum is immediately next to NSA’s headquarters in Ft Meade Maryland. It contains many very nice examples of systems, starting with completely manual systems and progressing through mechanical, electromechanical and then some very heavy duty computer-based systems, both for the transfer of secret messages, and also for breaking open those secret communications.