Elonka Dunin, known for her website on the World’s Most Famous Unsolved Codes, discovered a cipher on one of the tombstones in Arlington National Cemetery. Not just any tombstone, it’s that of William and Elizebeth Friedman, two giants in the fields of cryptanalysis. In fact, William Friedman created the terms of cryptanalysis, and also of “index of coincidence”. Elizebeth, who had taught William about cryptography in the first place, had an astonishing career cracking the codes of Nazis, drug smugglers, and rum-runners. They also wrote a book together examining and debunking the theories about whether William Shakespeare really wrote his own works. How did a geneticist and a Shakespearean scholar come to meet, and then have careers which grew and became the foundation of what is today known as the National Security Agency? How did they hide a cipher on their tombstone which remained undiscovered for so many years, and was found in the year that is the 100-year anniversary of their marriage? Tune in and find out!