20th century teleprinters also use punched tape. Herman Hollerith used punched tape for a census, in 1890. Gilbert Vernam, a telecommunication engineer developed the Vernam cipher in 1917. This cipher could be used with punched tape. Vernam combined a character of the punched tape, with one of a key, to give the encoded character. Combining the ecoded character with the key again gives the plain text. This is in fact an exclusive disjunction, even though Vernam used a different name. It was an automated one-time pad. The NSA has called this patent "perhaps one of the most important in the history of cryptography."