Last year, in celebration of its 60th anniversary, the National Security Agency published a digital memory book of declassified photos, audio tapes, and documents from its archives.
The multi-billion dollar agency first took shape in the 1930s, but its existence was kept a deep secret until a Senate investigation in the mid-70s.
Below are some of the most interesting from the NSA's archives:
The original members of the NSA are seen below in this photograph from 1935. At the time the organization was called the U.S. Army Signal Intelligence Service and was responsible for Army communications security.
The main responsibilities of NSA forerunners included decoding messages from foreign agents. A strip cipher device, such as the M-138 shown here, was used to by sliding a metal bar slid across a tablet of two scrambled alphabets.
President FDR's authorization of women to take noncombatant military roles during WWII led to a heightened role of female cryptologists. Women were expected to type at least 100 words per minute with extreme accuracy since one mistake would mislead the message.