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BID 770
The BID 770 was a British-built electronic cryptography device, codenamed TOPIC. It was also used by Canada's foreign service under the codename TENEC. TOPIC was brought into service in 1977, and became obsolete in 1995. TOPIC was used to protect telegraph traffic, and replaced the earlier mechanical system called ROCKEX. It could be operated in both on- and off-line modes. Weighing 65 lb, the machine used diode–transistor logic Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating function (e.g., AND) is performed by a diode network and the amplifying functio ... instead of single transistors. External links Jerry Proc's page on the BID 770 {{Cryptography navbox , machines Encryption devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TOPIC
Topic, topics, TOPIC, topical, or topicality may refer to: Topic / Topics * Topić, a Slavic surname * ''Topics'' (Aristotle), a work by Aristotle * Topic (chocolate bar), a brand of confectionery bar * Topic (DJ), German musician * Topic (grammar) * Topic (linguistics), the information motivating a sentence or clause's structure * '' Topic: The Washington & Jefferson College Review'', an academic journal * Topic Records, a British record label * In topic-based authoring, a topic is a discrete piece of content that is about a specific subject, has an identifiable purpose, and can stand alone * Topic Studios, a production organization and streaming video service run by First Look Media TOPIC * TOPIC, an Internet Relay Chat (IRC) command setting a channel's title * BID 770, a British cipher machine codenamed "TOPIC" Topicality * Topicality (policy debate) Topicality is a stock issue in policy debate which pertains to whether or not the plan affirms the resolution a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security ( data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ROCKEX
Rockex, or Telekrypton, was an offline one-time tape Vernam cipher machine known to have been used by Britain and Canada from 1943. It was developed by Canadian electrical engineer Benjamin deForest Bayly, working during the war for British Security Coordination. "Rockex" was named after the Rockefeller Center,Louis Kruh, British intelligence in the Americas, ''Cryptologia'', April 2001 together with the tradition for naming British cipher equipment with the suffix "-ex" (e.g. Typex). In 1944 an improved Rockex II first appeared. There were also a Mark III and Mark V. After the war it was used by British consulates and embassies until 1973, although a few continued in use until the mid-1980s.Exhibit card describing Rockex equipment in the "Enigma and Friends" exhibit at the Bletchley Park museum, September 2006 After WW2 the Rockex machines and the code tapes were manufactured in great secrecy under the control of the Secret Intelligence Service (SIS), also known as MI6, at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diode–transistor Logic
Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating function (e.g., AND) is performed by a diode network and the amplifying function is performed by a transistor (in contrast with RTL and TTL). Implementations The DTL circuit shown in the picture consists of three stages: an input diode logic stage (D1, D2 and R1), an intermediate level shifting stage (R3 and R4), and an output common-emitter amplifier stage (Q1 and R2). If both inputs A and B are high (logic 1; near V+), then the diodes D1 and D2 are reverse biased. Resistors R1 and R3 will then supply enough current to turn on Q1 (drive Q1 into saturation) and also supply the current needed by R4. There will be a small positive voltage on the base of Q1 (VBE, about 0.3 V for germanium and 0.6 V for silicon). The turned on transistor's collector current will then pull the output Q low (logic 0; VCE(sat), usuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
