Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both the encryption of plaintext and the decryption of ciphertext. The keys may be identical, or there may be a simple transformation to go between the two keys. The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link. The requirement that both parties have access to the secret key is one of the main drawbacks of symmetric-key encryption, in comparison to public-key encryption. However, symmetric-key encryption algorithms are usually better for bulk encryption. They have a smaller key size, which means less storage space and faster transmission. Due to this, asymmetric-key encryption is often used to exchange the secret key for symmetric-key encryption.
William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signal Intelligence Service (SIS) in the 1930s, and parts of its follow-on services into the 1950s. In 1940, subordinates of his led by Frank Rowlett broke Japan's PURPLE cipher, thus disclosing Japanese diplomatic secrets before America's entrance into World War II.
A book cipher, or Ottendorf cipher, is a cipher in which the key is some aspect of a book or other piece of text. Books, being common and widely available in modern times, are more convenient for this use than objects made specifically for cryptographic purposes. It is typically essential that both correspondents not only have the same book, but the same edition.
Leon Ames was an American film and television actor. He is best remembered for playing father figures in such films as Meet Me in St. Louis (1944) with Judy Garland as one of his daughters, Little Women (1949), On Moonlight Bay (1951), and By the Light of the Silvery Moon (1953). The fathers whom Ames portrayed were often somewhat stuffy and exasperated by the younger generation, but ultimately kind and understanding. Probably his best-known purely dramatic role was as DA Kyle Sackett in the crime film The Postman Always Rings Twice (1946).
Cryptanalysis of the Enigma ciphering system enabled the western Allies in World War II to read substantial amounts of Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio and teleprinter transmissions, was given the codename Ultra.
Thirty Seconds Over Tokyo is a 1944 American war film produced by Metro-Goldwyn-Mayer. The screenplay by Dalton Trumbo is based on the 1943 book of the same name by Captain Ted W. Lawson. Lawson was a pilot on the historic Doolittle Raid, America's first retaliatory air strike against Japan, four months after the December 7, 1941, Japanese attack on Pearl Harbor. The raid was planned, led by, and named after United States Army Air Forces Lieutenant Colonel James Doolittle, who was promoted two ranks, to Brigadier General, the day after the raid.
Enigma is a 2001 espionage thriller film directed by Michael Apted from a screenplay by Tom Stoppard. The script was adapted from the 1995 novel Enigma by Robert Harris, about the Enigma codebreakers of Bletchley Park in the Second World War.
Cipher Bureau is a 1938 American film directed by Charles Lamont. The film was successful enough to elicit a sequel, Panama Patrol.
Below is a timeline of notable events related to cryptography.
The Gouzenko Affair was the name given to events in Canada surrounding the defection of Igor Gouzenko from the Soviet Union in 1945 and his subsequent allegations regarding the existence of a Soviet spy ring of Canadian Communists. Gouzenko's defection and revelations are considered by historians to have marked the beginning of the Cold War in Canada, as well as potentially setting the stage for the "Red Scare" of the 1950s.
The Portland Spy Ring was a Soviet spy ring that operated in England from the late 1950s to 1961, when the core of the network was arrested by the British security services. It is one of the most famous examples of the use of resident spies, who operate in a foreign country without the cover of their embassy. Its members included Harry Houghton, Ethel Gee, Gordon Lonsdale, and the Americans Morris and Lona Cohen.
The Secret Code (1942) was the 19th serial released by Columbia Pictures. It features the masked hero "The Black Commando" facing Nazi saboteurs, inspired by Republic Pictures' successful Spy Smasher serial of the same year. The chapters of this serial each ended with a brief tutorial in cryptography.
David Hay Petrie was a Scottish actor noted for playing eccentric characters, among them Quilp in The Old Curiosity Shop (1934), the McLaggen in The Ghost Goes West (1935) and Uncle Pumblechook in Great Expectations (1946).
Reino Häyhänen was a Soviet intelligence officer of the KGB who defected from the Soviet Union to the United States in May 1957. Häyhänen surrendered information on Soviet espionage activities that solved the Hollow Nickel Case for the FBI, and led to the arrest of his KGB partner Rudolf Abel and other Soviet spies in the United States and Canada.
Death in the Air is a 1937 American film directed by Elmer Clifton and stars Lona Andre, John Carroll, Leon Ames and Henry Hall. The film is also known as Murder in the Air in the United Kingdom and as The Mysterious Bombardier. The film was Fanchon Royer's first production for her new company, Fanchon Royer Features, Inc. Film Daily reported that noted "G-Man" Melvin Purvis was offered a role in this film, but turned it down.
Marie Galante is a 1934 American film directed by Henry King, starring Ketti Gallian and Spencer Tracy, adapted from a French novel by Jacques Deval. Later in the same year the novel was adapted into a French musical titled Marie Galante, with book and lyrics by Jacques Deval and music by Kurt Weill.
Dangerously They Live is a 1941 American World War II spy film directed by Robert Florey and starring John Garfield, Nancy Coleman and Raymond Massey. The plot concerns Nazi spies who try to pry information out of a British agent.
Sabre Jet is a 1953 American Korean War war film drama directed by Louis King starring Robert Stack, Coleen Gray, Richard Arlen, Julie Bishop and Leon Ames. Shot in Cinecolor using United States Air Force footage. Sabre Jet was based on a story by the producer Carl Krueger with the screenplay written by the husband and wife playwright and screenwriting team of Dale Eunson and Katherine Albert. The opening credits state: "This picture is dedicated to the air force wives who shared their men with a world made desperate by the most brutal aggressor in history."
A Passport to Hell is a 1932 American pre-Code drama film directed by Frank Lloyd and written by Leon Gordon and Bradley King. The film stars Elissa Landi, Paul Lukas, Warner Oland, Alexander Kirkland, Donald Crisp and Earle Foxe. The film was released on August 14, 1932, by Fox Film Corporation.
Lionel Royce was an Austrian-American actor of stage and screen, also known during his European career as Leo Reuss. He began his career in theater in Vienna, Austria, in 1919, before moving to Berlin in 1925. Being Jewish, his work began to be restricted in the 1930s in Nazi Germany. Fleeing the Nazis he returned to Austria in 1936, where to hide his heritage, he created the persona of Kaspar Brandhofer, a Tyrolian peasant, and became a sensation as a natural actor on the stage in Vienna. When he admitted his ruse, he became blacklisted in Austria, after which he emigrated to the United States in 1937. He had an active film career in the United States, appearing in almost 40 films between 1938 and 1946. While on tour with the USO, he died in Manila in 1946.
