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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] |
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] |
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 SIGCUM was subsequently discovered to be insecure by Rowlett, and was immediately withdrawn from service.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] |
Tempest (codename)
TEMPEST is a U.S. National Security Agency specification and a NATO certification referring to spying on information systems through leaking emanations, including unintentional radio or electrical signals, sounds, and vibrations. TEMPEST covers both methods to spy upon others and how to shield equipment against such spying. The protection efforts are also known as emission security (EMSEC), which is a subset of communications security (COMSEC). The NSA methods for spying on computer emissions are classified, but some of the protection standards have been released by either the NSA or the Department of Defense. Protecting equipment from spying is done with distance, shielding, filtering, and masking. The TEMPEST standards mandate elements such as equipment distance from walls, amount of shielding in buildings and equipment, and distance separating wires carrying classified vs. unclassified materials, filters on cables, and even distance and shielding between wires or equipment and b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TTY Mixer 131B2 TM-11-2222 Fig 3
TTY may refer to: Communications and technology * Teleprinter or teletypewriter (TTY), an electromechanical typewriter paired with a communication channel ** Sometimes used more generally for any type of computer terminal ** Sometimes used for a virtual console, typically accessed by ++ and identified as tty1, tty2, tty3, etc. * Another name for a telecommunications device for the deaf (TDD), a teleprinter designed for persons with hearing or speech difficulties * tty (Unix), a command found in Unix-like operating systems Other uses * Tampere University of Technology Tampere University of Technology (TUT) ( fi, Tampereen teknillinen yliopisto (TTY)) was Finland's second-largest university in engineering sciences. The university was located in Hervanta, a suburb of Tampere. It was merged with the University o ... (Tampereen Teknillinen Yliopisto), in Finland * Torque-to-yield fastener {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleprinter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering, though teleprinters were not used for telegraphy until 1887 at the earliest. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage (either from typed input or from data received from a remote source) and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media. These included a simple pair of wires; dedicated non-switched telephone circuits (leased lines); switched network ... [...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] |
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] |
5-UCO
The 5-UCO (5-Unit Controlled)Ralph Erskine, "The 1944 Naval BRUSA Agreement and its Aftermath", ''Cryptologia'' 30(1), January 2006 pp14–15 was an on-line one-time tape Vernam cipher encryption system developed by the UK during World War II for use on teleprinter circuits. During the 1950s, it was used by the UK and US for liaison on cryptanalysis. 5-UCO was fully synchronous, and therefore could be electrically regenerated on tandem high frequency (HF) radio links (i.e. one link connected to the next). It could operate directly with commercial circuits. The system also provided traffic-flow security (TFS). Another feature of the 5-UCO was that the receiving operator could maintain synchronisation if the path delay suddenly changed by "walking up and down" the key tape (one character at a time or one bit at a time). This procedure avoided the cumbersome task of a restart.Melville Klein, "Securing Record Communications: The TSEC/KW-26", 2003, NSA brochure, p. 4(PDF)/ref> 5- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Flow Security
Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication, it can be performed even when the messages are encrypted. In general, the greater the number of messages observed, the greater information be inferred. Traffic analysis can be performed in the context of military intelligence, counter-intelligence, or pattern-of-life analysis, and is also a concern in computer security. Traffic analysis tasks may be supported by dedicated computer software programs. Advanced traffic analysis techniques which may include various forms of social network analysis. Traffic analysis has historically been a vital technique in cryptanalysis, especially when the attempted crack depends on successfully seeding a known-plaintext attack, which often requires an inspired guess based on how specific the operational context might likely influence what an adversary communicates, which may be sufficient to establish a short crib. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Army Security Agency
The United States Army Security Agency (ASA) was the United States Army's signals intelligence branch from 1945 to 1976. The Latin motto of the Army Security Agency was ''Semper Vigiles'' (Vigilant Always), which echoes the declaration, often mistakenly attributed to Thomas Jefferson, that " The price of liberty is eternal vigilance." Although most ASA units focused upon SIGINT (signals intelligence) most if not all ASA units contained HUMINT (human intelligence) specialists as well, mostly interrogators and counter-intelligence specialists. At the end of the Cold War era, some ASA units also were staffed with ELINT (electronic intelligence) specialists and warrant officers, which incorporated field ECM (electronic counter-measures and field ECCM (electronic counter-countermeasures) such as tactical jammers, direction finders, electronic signal decoys, and captured/repurposed Warsaw Pact radio and communications equipment. The Agency existed between 1945 and 1977 and was the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Security Agency
The National Security Agency (NSA) is a national-level intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence (DNI). The NSA is responsible for global monitoring, collection, and processing of information and data for foreign and domestic intelligence and counterintelligence purposes, specializing in a discipline known as signals intelligence (SIGINT). The NSA is also tasked with the protection of U.S. communications networks and information systems. The NSA relies on a variety of measures to accomplish its mission, the majority of which are clandestine. The existence of the NSA was not revealed until 1975. The NSA has roughly 32,000 employees. Originating as a unit to decipher coded communications in World War II, it was officially formed as the NSA by President Harry S. Truman in 1952. Between then and the end of the Cold War, it became the largest of the U.S. intelligence organizations in terms of pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
