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SIGCUM
SIGCUM, also known as Converter M-228, was a rotor cipher machine used to encrypt teleprinter traffic by the United States Army. Hastily designed by William Friedman and Frank Rowlett, the system was put into service in January 1943 before any rigorous analysis of its security had taken place. SIGCUM was subsequently discovered to be insecure by Rowlett, and was immediately withdrawn from service. The machine was redesigned to improve its security, reintroduced into service by April 1943, and remained in use until the 1960s. Development In 1939, Friedman and Rowlett worked on the problem of creating a secure teleprinter encryption system. They decided against using a tape-based system, such as those proposed by Gilbert Vernam, and instead conceived of the idea of generating a stream of five-bit pulses by use of wired rotors. Because of lack of funds and interest, however, the proposal was not pursued any further at that time. This changed with the United States' entry into World ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIGCUM
SIGCUM, also known as Converter M-228, was a rotor cipher machine used to encrypt teleprinter traffic by the United States Army. Hastily designed by William Friedman and Frank Rowlett, the system was put into service in January 1943 before any rigorous analysis of its security had taken place. SIGCUM was subsequently discovered to be insecure by Rowlett, and was immediately withdrawn from service. The machine was redesigned to improve its security, reintroduced into service by April 1943, and remained in use until the 1960s. Development In 1939, Friedman and Rowlett worked on the problem of creating a secure teleprinter encryption system. They decided against using a tape-based system, such as those proposed by Gilbert Vernam, and instead conceived of the idea of generating a stream of five-bit pulses by use of wired rotors. Because of lack of funds and interest, however, the proposal was not pursued any further at that time. This changed with the United States' entry into World ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor Machine
In cryptography, a rotor machine is an electro-mechanical stream cipher device used for encrypting and decrypting messages. Rotor machines were the cryptographic state-of-the-art for much of the 20th century; they were in widespread use in the 1920s–1970s. The most famous example is the German Enigma machine, the output of which was deciphered by the Allies during World War II, producing intelligence code-named ''Ultra''. Description The primary component of a rotor machine is a set of ''rotors'', also termed ''wheels'' or ''drums'', which are rotating disks with an array of electrical contacts on either side. The wiring between the contacts implements a fixed substitution of letters, replacing them in some complex fashion. On its own, this would offer little security; however, before or after encrypting each letter, the rotors advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher, which changes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor Machines
In cryptography, a rotor machine is an electro-mechanical stream cipher device used for encrypting and decrypting messages. Rotor machines were the cryptographic state-of-the-art for much of the 20th century; they were in widespread use in the 1920s–1970s. The most famous example is the German Enigma machine, the output of which was deciphered by the Allies during World War II, producing intelligence code-named ''Ultra''. Description The primary component of a rotor machine is a set of ''rotors'', also termed ''wheels'' or ''drums'', which are rotating disks with an array of electrical contacts on either side. The wiring between the contacts implements a fixed substitution of letters, replacing them in some complex fashion. On its own, this would offer little security; however, before or after encrypting each letter, the rotors advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher, which changes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIGTOT
SIGTOT was a one-time tape machine for encrypting teleprinter communication that was used by the United States during World War II and after for the most sensitive message traffic. It was developed after security flaws were discovered in an earlier rotor machine for the same purpose, called SIGCUM. SIGTOT was designed by Leo Rosen and used the same Bell Telephone 132B2 mixer as SIGCUM. The British developed a similar machine called the 5-UCO. Later an improved mixer, the SSM-33, replaced the 131B2, The phenomenon, codenamed TEMPEST, of sensitive information leaking by way of unintended electromagnetic radiation for the circuits used inside encryption machine was first discovered coming from the 131B2 mixers used in SIGTOT. References History of cryptography Encryption devices {{crypto-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIGABA
In the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s. The machine was also known as the SIGABA or Converter M-134 by the Army, or CSP-888/889 by the Navy, and a modified Navy version was termed the CSP-2900. Like many machines of the era it used an electromechanical system of rotors to encipher messages, but with a number of security improvements over previous designs. No successful cryptanalysis of the machine during its service lifetime is publicly known. History It was clear to US cryptographers well before World War II that the single-stepping mechanical motion of rotor machines (e.g. the Hebern machine) could be exploited by attackers. In the case of the famous Enigma machine, these attacks were supposed to be upset by moving the rotors to random locations at the start of each new message. This, however, proved not to be secure enough, and German Enigma messages were freque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army
The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, clause 1 of the United States Constitution (1789). See alsTitle 10, Subtitle B, Chapter 301, Section 3001 The oldest and most senior branch of the U.S. military in order of precedence, the modern U.S. Army has its roots in the Continental Army, which was formed 14 June 1775 to fight the American Revolutionary War (1775–1783)—before the United States was established as a country. After the Revolutionary War, the Congress of the Confederation created the United States Army on 3 June 1784 to replace the disbanded Continental Army.Library of CongressJournals of the Continental Congress, Volume 27/ref> The United States Army considers itself to be a continuation of the Continental Army, and thus considers its institutional inception to be th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algiers
Algiers ( ; ar, الجزائر, al-Jazāʾir; ber, Dzayer, script=Latn; french: Alger, ) is the capital and largest city of Algeria. The city's population at the 2008 Census was 2,988,145Census 14 April 2008: Office National des Statistiques de l'Algérie (web). and in 2020 was estimated to be around 4,500,000. Algiers is located on the Mediterranean Sea and in the north-central portion of Algeria. Algiers is situated on the west side of a bay of the Mediterranean Sea. The modern part of the city is built on the level ground by the seashore; the old part, the ancient city of the deys, climbs the steep hill behind the modern town and is crowned by the Casbah or citadel (a UNESCO World Heritage Site), above the sea. The casbah and the two quays form a triangle. Names The city's name is derived via French and Catalan ''Origins of Algiers'' by Louis Leschi, speech delivered June 16, 1941, published in ''El Djezair Sheets'', July 194History of Algeria . from the Arabic name '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leo Rosen
Leo Rosen was a U.S. cryptanalyst who worked with Frank Rowlett at Signals Intelligence Service (S.I.S.) before the start of World War II on Japanese ciphers. Rowlett found a method to read the messages enciphered on the Japanese PURPLE machine. Rosen deduced correctly the mechanism of the cipher machine, even though the mechanism used by PURPLE, telephone stepping switches, was substantially different from other machines (such as the wired rotor and pinwheel machines). Rosen built a replica of PURPLE which turned out (when a machine was found years later) to use stepping switches similar to those in common use at that time in the U.S. This machine was used to decode the Japanese diplomatic messages, sometimes before the Japanese ambassadors had themselves. Rosen also contributed his engineering talents during and after the war at Arlington Hall, after the S.I.S. became the Army Security Agency, later to become AFSA and finally the present National Security Agency. In 2010 he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One-time Tape
In cryptography, the one-time pad (OTP) is an encryption technique that cannot be cracked, but requires the use of a single-use pre-shared key that is not smaller than the message being sent. In this technique, a plaintext is paired with a random secret key (also referred to as ''a one-time pad''). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using modular addition. The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met: #The key must be at least as long as the plaintext. #The key must be random ( uniformly distributed in the set of all possible keys and independent of the plaintext), entirely sampled from a non-algorithmic, chaotic source such as a hardware random number generator. It is not sufficient for OTP keys to pass statistical randomness tests as such tests cannot measure entropy, and the number of bits of entropy must be at least equal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plaintext
In cryptography, plaintext usually means unencrypted information pending input into cryptographic algorithms, usually encryption algorithms. This usually refers to data that is transmitted or stored unencrypted. Overview With the advent of computing, the term ''plaintext'' expanded beyond human-readable documents to mean any data, including binary files, in a form that can be viewed or used without requiring a key or other decryption device. Information—a message, document, file, etc.—if to be communicated or stored in an unencrypted form is referred to as plaintext. Plaintext is used as input to an encryption algorithm; the output is usually termed ciphertext, particularly when the algorithm is a cipher. Codetext is less often used, and almost always only when the algorithm involved is actually a code. Some systems use multiple layers of encryption, with the output of one encryption algorithm becoming "plaintext" input for the next. Secure handling Insecure handling of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptanalysis
Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown. In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation. Even though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematically advanced comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teletype Corporation
The Teletype Corporation, a part of American Telephone and Telegraph Company's Western Electric manufacturing arm since 1930, came into being in 1928 when the Morkrum-Kleinschmidt Company changed its name to the name of its trademark equipment. Teletype Corporation, of Skokie, Illinois, was responsible for the research, development and manufacture of data and record communications equipment, but it is primarily remembered for the manufacture of electromechanical teleprinters. Because of the nature of its business, as stated in the corporate charter, Teletype Corporation was allowed a unique mode of operation within Western Electric. It was organized as a separate entity, and contained all the elements necessary for a separate corporation. Teletype's charter permitted the sale of equipment to customers outside the AT&T Bell System, which explained their need for a separate sales force. The primary customer outside of the Bell System was the United States Government. The Teletype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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