Editing One-time pad (section)

===NSA===
At least into the 1970s, the U.S. [[National Security Agency]] (NSA) produced a variety of manual one-time pads, both general purpose and specialized,  with 86,000 one-time pads produced in fiscal year 1972. Special purpose pads were produced for what the NSA called "pro forma" systems, where "the basic framework, form or format of every message text is identical or nearly so; the same kind of information, message after message, is to be presented in the same order, and only specific values, like numbers, change with each message." Examples included nuclear launch messages and radio direction finding reports (COMUS).<ref name=boaklectures1>{{Cite book
 |last        = Boak
 |first       = David G.
 |title       = A History of U.S. Communications Security; the David G. Boak Lectures, Vol. I
 |orig-year   = 1966
 |url         = https://www.governmentattic.org/18docs/Hist_US_COMSEC_Boak_NSA_1973u.pdf
 |access-date = 2017-04-23
 |edition     = 2015 declassification review
 |date        = July 1973
 |publisher   = U.S. National Security Agency
 |location    = Ft. George G. Meade, MD
 |url-status  = dead
 |archive-url  = https://web.archive.org/web/20170525181251/http://www.governmentattic.org/18docs/Hist_US_COMSEC_Boak_NSA_1973u.pdf
 |archive-date = 2017-05-25
}}</ref>{{rp|pp. 16–18}}

General purpose pads were produced in several formats, a simple list of random letters (DIANA) or just numbers (CALYPSO), tiny pads for covert agents (MICKEY MOUSE), and pads designed for more rapid encoding of short messages, at the cost of lower density. One example, ORION, had 50 rows of plaintext alphabets on one side and the corresponding random cipher text letters on the other side. By placing a sheet on top of a piece of [[carbon paper]] with the carbon face up, one could circle one letter in each row on one side and the corresponding letter on the other side would be circled by the carbon paper. Thus one ORION sheet could quickly encode or decode a message up to 50 characters long. Production of ORION pads required printing both sides in exact registration, a difficult process, so NSA switched to another pad format, MEDEA, with 25 rows of paired alphabets and random characters. (''See'' [[Commons:Category:NSA one-time pads]] for illustrations.)

The NSA also built automated systems for the "centralized headquarters of CIA and Special Forces units so that they can efficiently process the many separate one-time pad messages to and from individual pad holders in the field".<ref name=boaklectures1 />{{rp|pp. 21–26}}

During World War II and into the 1950s, the U.S. made extensive use of one-time tape systems. In addition to providing confidentiality, circuits secured by  one-time tape ran continually, even when there was no traffic, thus protecting against [[traffic analysis]]. In 1955, NSA produced some 1,660,000 rolls of one time tape. Each roll was 8 inches in diameter, contained 100,000 characters, lasted 166 minutes and cost $4.55 to produce. By 1972, only 55,000 rolls were produced, as one-time tapes were replaced by [[rotor machine]]s such as SIGTOT, and later by electronic devices based on [[shift registers]].<ref name=boaklectures1 />{{rp|pp. 39–44}} The NSA describes one-time tape systems like [[5-UCO]] and SIGTOT as being used for intelligence traffic until the introduction of the electronic cipher based [[KW-26]] in 1957.<ref>{{cite web| url=http://www.nsa.gov/publications/publi00017.pdf| title=Securing Record Communications: The TSEC/KW-26| year=2003| access-date=2006-05-12| first=Melville| last=Klein| publisher=NSA |archive-url = https://web.archive.org/web/20060213165531/http://www.nsa.gov/publications/publi00017.pdf <!-- Bot retrieved archive --> |archive-date = 2006-02-13}}</ref>