Elizebeth Smith Friedman (August 26, 1892 – October 31, 1980) was a cryptanalyst and author, and a pioneer in U.S. cryptography. She has been dubbed "America's first female cryptanalyst".
She was the wife of William Frederick Friedman, a notable cryptographer credited with numerous contributions to cryptology. She, however, enjoyed many successes in her own right, and it was Elizebeth who first introduced her husband to the field.
The couple were also involved in cryptographical analysis of the Shakespeare corpus, and disproving the contention that Francis Bacon wrote the plays.
The Friedmans donated their archives to the George C. Marshall Foundation.