|
Codebooks
A codebook is a type of document used for gathering and storing cryptography codes. Originally codebooks were often literally , but today codebook is a byword for the complete record of a series of codes, regardless of physical format. Cryptography In cryptography, a codebook is a document used for implementing a code. A codebook contains a lookup table for coding and decoding; each word or phrase has one or more strings which replace it. To decipher messages written in code, corresponding copies of the codebook must be available at either end. The distribution and physical security of codebooks presents a special difficulty in the use of codes, compared to the secret information used in ciphers, the key, which is typically much shorter. The United States National Security Agency documents sometimes use ''codebook'' to refer to block ciphers; compare their use of ''combiner-type algorithm'' to refer to stream ciphers. Codebook come in two forms, one-part or two-part: * In one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography Code
In cryptology, a code is a method used to encrypt a message that operates at the level of meaning; that is, words or phrases are converted into something else. A code might transform "change" into "CVGDK" or "cocktail lounge". The U.S. National Security Agency defined a code as "A substitution cryptosystem in which the plaintext elements are primarily words, phrases, or sentences, and the code equivalents (called "code groups") typically consist of letters or digits (or both) in otherwise meaningless combinations of identical length."A History of U.S. Communications Security; the David G. Boak Lectures National Security Agency (NSA), Volumes I, 1973, Volumes II 1981, partially released 2008, additional portions declassified October 14, 2015 A ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code (cryptography)
In cryptology, a code is a method used to encrypt a message that operates at the level of meaning; that is, words or phrases are converted into something else. A code might transform "change" into "CVGDK" or "cocktail lounge". The U.S. National Security Agency defined a code as "A substitution cryptosystem in which the plaintext elements are primarily words, phrases, or sentences, and the code equivalents (called "code groups") typically consist of letters or digits (or both) in otherwise meaningless combinations of identical length."A History of U.S. Communications Security; the David G. Boak Lectures National Security Agency (NSA), Volumes I, 1973, Volumes II 1981, partially released 2008, additional portions declassified October 14, 2015 A '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JN-25
The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well. Every Japanese code was eventually broken, and the intelligence gathered made possible such operations as the victorious American ambush of the Japanese Navy at Midway in 1942 (by breaking code JN-25b) and the shooting down of Japanese admiral Isoroku Yamamoto a year later in Operation Vengeance. The Imperial Japanese Navy (IJN) used many codes and ciphers. All of these cryptosystems were known differently by different organizations; the names listed below are those given by Western cryptanalytic operations. Red code The Red Book code was an IJN code book system used in World War I and after. It was called "Red Book" because the American photographs made of it were bound in red covers.Greg Goebel"US Codebreakers In The Shadow Of War" 2018. It should not be confu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precoding
Precoding is a generalization of beamforming to support multi-stream (or multi-layer) transmission in multi-antenna wireless communications. In conventional single-stream beamforming, the same signal is emitted from each of the transmit antennas with appropriate weighting (phase and gain) such that the signal power is maximized at the receiver output. When the receiver has multiple antennas, single-stream beamforming cannot simultaneously maximize the signal level at all of the receive antennas. In order to maximize the throughput in multiple receive antenna systems, multi-stream transmission is generally required. In point-to-point systems, precoding means that multiple data streams are emitted from the transmit antennas with independent and appropriate weightings such that the link throughput is maximized at the receiver output. In multi-user MIMO, the data streams are intended for different users (known as SDMA) and some measure of the total throughput (e.g., the sum performan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commercial Code (communications)
In telecommunication, a commercial code is a code once used to save on cablegram costs. Telegraph (and telex) charged per word sent, so companies which sent large volumes of telegrams developed codes to save money on tolls. Elaborate commercial codes which encoded complete phrases into single words were developed and published as codebooks of thousands of phrases and sentences with corresponding codewords. Commercial codes were not generally intended to keep telegrams private, as codes were widely published; they were usually cost-saving measures only. Many general-purpose codes, such as the ''Acme Code'' and the ''ABC Code'', were published and widely used between the 1870s and the 1950s, before the arrival of transatlantic telephone calls and next-day airmail rendered them obsolete. Numerous special-purpose codes were also developed and sold for fields as varied as aviation, car dealerships, insurance, and cinema, containing words and phrases commonly used in those professions. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
State Department Code Book 1899, Open To Title Page, At NMC
State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * ''Our State'', a monthly magazine published in North Carolina and formerly called ''The State'' * The State (Larry Niven), a fictional future government in three novels by Larry Niven Music Groups and labels * States Records, an American record label * The State (band), Australian band previously known as the Cutters Albums * State (album), ''State'' (album), a 2013 album by Todd Rundgren * States (album), ''States'' (album), a 2013 album by the Paper Kites * ''States'', a 1991 album by Klinik * The State (album), ''The State'' (album), a 1999 album by Nickelback Television * The State (American TV series), ''The State'' (American TV series), 1993 * The State (British TV series), ''The State'' (British TV series), 2017 Oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomenclator (nomenclature)
A nomenclator ( ; English plural nomenclators, Latin plural nomenclatores; derived from the Latin ''nomen''- name + ''calare'' - to call), in classical times, referred to a slave whose duty was to recall the names of persons his master met during a political campaign. Later this became names of people in any social context and included other socially important information. However, it has taken on several other meanings and also refers to a book containing collections or lists of words. It also denotes a person, generally a public official, who announces the names of guests at a party or other social gathering or ceremony. In more general terms still, it is a person who provides or creates the names for things, and this can apply to the application of names in a scientific or any other context, but especially in relation to specialist terminologies, glossaries etc. Nomenclators in biology Several nomenclators have been created in biology. They usually list the names of gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Code Book
''The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography'' is a book by Simon Singh, published in 1999 by Fourth Estate and Doubleday. ''The Code Book'' describes some illustrative highlights in the history of cryptography, drawn from both of its principal branches, codes and ciphers. Thus the book's title should not be misconstrued as suggesting that the book deals only with codes, and not with ciphers; or that the book is in fact a codebook. Contents ''The Code Book'' covers diverse historical topics including the Man in the Iron Mask, Arabic cryptography, Charles Babbage, the mechanisation of cryptography, the Enigma machine, and the decryption of Linear B and other ancient writing systems. Later sections cover the development of public-key cryptography. Some of this material is based on interviews with participants, including persons who worked in secret at GCHQ. The book concludes with a discussion of "Pretty Good Privacy" (PGP), quantum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block Cipher Modes Of Operation
In cryptography, a block cipher mode of operation is an algorithm that uses a block cipher to provide information security such as confidentiality or authenticity. A block cipher by itself is only suitable for the secure cryptographic transformation (encryption or decryption) of one fixed-length group of bits called a block. A mode of operation describes how to repeatedly apply a cipher's single-block operation to securely transform amounts of data larger than a block. Most modes require a unique binary sequence, often called an initialization vector (IV), for each encryption operation. The IV has to be non-repeating and, for some modes, random as well. The initialization vector is used to ensure distinct ciphertexts are produced even when the same plaintext is encrypted multiple times independently with the same key. Block ciphers may be capable of operating on more than one block size, but during transformation the block size is always fixed. Block cipher modes operate on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTE (telecommunication)
In telecommunications, long-term evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE frequencies and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported. The standard is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9. LTE is also called 3.95G and has been marketed as "4G LTE" and "Advanced 4G"; but it does not meet the technical criteria of a 4G wireless service, as specified in the 3GPP Release 8 and 9 document series for LTE Advanced. The requirements were set forth by the ITU-R organisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beamforming
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity. The improvement compared with omnidirectional reception/transmission is known as the directivity of the array. Beamforming can be used for radio or sound waves. It has found numerous applications in radar, sonar, seismology, wireless communications, radio astronomy, acoustics and biomedicine. Adaptive beamforming is used to detect and estimate the signal of interest at the output of a sensor array by means of optimal (e.g. least-squares) spatial filtering and interference rejection. Techniques To change the directionality of the array when transm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
