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Influence the cryptologic future by sharing our educational resources, stimulating new knowledge, & commemorating our heritage.

1919: Patent issued to Gilbert Vernam for concept of machine encipherment.

Friday, July 22, 2022

22 July 1919: Patent issued to Gilbert Vernam for a "Secret Signaling System," which describes an automated teletype cipher.

In this automated system, a loop of perforated paper tape representing random letters was added to a plaintext message to create the ciphertext. On the receiving end, a duplicate loop would be used to subtract the same random letters from the ciphertext to re-create the plaintext message. The advantage was the encipherment and decipherment was handled automatically without human intervention or error. The use of a loop of tape meant the system was not truly a one-time pad since the key tape would be reused, so it was vulnerable to enemy decryption. (Excerpted from ciphermachines.com)

The US military SIGTOT teletype system was the first use of an automated one-time tape, used by the US military. It was introduced in 1925 and was the "Secret Signaling System" directly based on Vernam's 1919 patent. It remained in use by the US military until the 1959. In the photo is a Special Transmitter/Distributor for the US military SIGTOT teletype cipher. The one pictured here was used in President Roosevelt's airplane and is now at the NCM.

Gilbert Vernam was an inventor who held 65 patents in the field of communication. He made significant contributions to the science of cryptography, and to the present-day, world-wide telegraph communications systems.

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The NCF's Vision is to Influence the cryptologic future by sharing our educational resources, stimulating new knowledge, and commemorating our heritage.

The Foundation provides exceptional cryptologic programs throughout the year, encourages young minds to explore cryptology and cyber education and careers,  hosts educational, cryptology-related exhibits at various community events, and honors the people— past, present, and future—whose contributions to our national security protect and make possible our way of life.

The NCF also provides needed support to the National Cryptologic Museum (NCM), the first public museum in the U.S. Intelligence Community. Located adjacent to the National Security Agency (NSA) in Maryland, the NCM houses a unique and priceless collection of artifacts that represent our Nation's history in code making and code breaking, as well as a world class library of cryptologic media. The NCF acquires the best artifacts for the Museum and supports new educational and interactive exhibits.

As part of the Foundation's partnership with NSA to build the Cyber Center for Education and Innovation - Home of the National Cryptologic Museum (CCEI-NCM), the NCF also serves as a leader in the field of cybersecurity - striving to provide the best in educational resources and programs.

The NCF has a three-part mission to Educate, Stimulate, and Commemorate. Learn more about our MISSION.