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Two-square Cipher
The Two-square cipher, also called double Playfair, is a manual symmetric encryption technique. It was developed to ease the cumbersome nature of the large encryption/decryption matrix used in the four-square cipher while still being slightly stronger than the single-square Playfair cipher. The technique encrypts pairs of letters (''digraphs''), and thus falls into a category of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers, which operate on single characters. The use of digraphs makes the two-square technique less susceptible to frequency analysis attacks, as the analysis must be done on 676 possible digraphs rather than just 26 for monographic substitution. The frequency analysis of digraphs is possible, but considerably more difficult, and it generally requires a much larger ciphertext in order to be useful. History Félix Delastelle described the cipher in his 1901 book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetric Key Algorithm
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 (also known as asymmetric-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. Types Symmetric-key encryption can use either stream ciphers or block ciphers. * Stream ciphers encrypt the digits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collier's Encyclopedia
''Collier's Encyclopedia'' is a discontinued general encyclopedia first published in 1949 by P. F. Collier and Son in the United States. With ''Encyclopedia Americana'' and ''Encyclopædia Britannica, Collier's Encyclopedia'' became one of the three major English-language general encyclopedias'':'' The three were sometimes collectively called "the ABCs". In 1998, Microsoft acquired the right to use ''Collier's Encyclopedia'' content from Atlas Editions, which had by then absorbed Collier Newfield. Microsoft incorporated ''Collier's Encyclopedia'''s content into its ''Encarta'' digital multimedia encyclopedia, which it marketed until 2009. ''Collier's Encyclopedia'' was an entirely new, 20 volume work, with the first volumes available in 1949 and all volumes published by 1951. It had more than 2,000 contributors, included 10,000 black and white illustrations, 96 pages of four-color illustrations, 126 colored maps and 100 black and white line maps. There were more than 400,000 inde ... [...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] |
Four-square Cipher
The four-square cipher is a manual symmetric encryption technique. It was invented by the French cryptographer Felix Delastelle. The technique encrypts pairs of letters (''digraphs''), and thus falls into a category of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers which operate on single characters. The use of digraphs makes the four-square technique less susceptible to frequency analysis attacks, as the analysis must be done on 676 possible digraphs rather than just 26 for monographic substitution. The frequency analysis of digraphs is possible, but considerably more difficult - and it generally requires a much larger ciphertext in order to be useful. Using four-square The four-square cipher uses four 5 by 5 (5x5) matrices arranged in a square. Each of the 5 by 5 matrices contains the letters of the alphabet (usually omitting "Q" or putting both "I" and "J" in the same ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed Alphabet , a person who is of multiple races
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Mixed is the past tense of ''mix''. Mixed may refer to: * Mixed (United Kingdom ethnicity category), an ethnicity category that has been used by the United Kingdom's Office for National Statistics since the 1991 Census * ''Mixed'' (album), a compilation album of two avant-garde jazz sessions featuring performances by the Cecil Taylor Unit and the Roswell Rudd Sextet See also * Mix (other) * Mixed breed, an animal whose parents are from different breeds or species * Mixed ethnicity Mixed race people are people of more than one race or ethnicity. A variety of terms have been used both historically and presently for mixed race people in a variety of contexts, including ''multiethnic'', ''polyethnic'', occasionally ''bi-ethn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helen Fouché Gaines
Helen Fouché Gaines (October 12, 1888 – April 2, 1940) was a member of the American Cryptogram Association and editor of the book ''Cryptanalysis'' (originally ''Elementary Cryptanalysis'') first published in 1939. The book described the principal cryptographic systems of the 19th century and cracking methods including elementary contact analysis (cryptanalysis). Her pen name A pen name, also called a ''nom de plume'' or a literary double, is a pseudonym (or, in some cases, a variant form of a real name) adopted by an author and printed on the title page or by-line of their works in place of their real name. A pen na ... was PICCOLA. Shortly after the publication of the book, she died. Publications * References External links ACA history of the book from ''The ACA and you'' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Transposition
In cryptography, a transposition cipher is a method of encryption which scrambles the positions of characters (''transposition'') without changing the characters themselves. Transposition ciphers reorder units of plaintext (typically characters or groups of characters) according to a regular system to produce a ciphertext which is a permutation of the plaintext. They differ from substitution ciphers, which do not change the position of units of plaintext but instead change the units themselves. Despite the difference between transposition and substitution operations, they are often combined, as in historical ciphers like the ADFGVX cipher or complex high-quality encryption methods like the modern Advanced Encryption Standard (AES). General principle Plaintexts can be rearranged into a ciphertext using a key, scrambling the order of characters like the shuffled pieces of a jigsaw puzzle. The resulting message is hard to decipher without the key because there are many ways the char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polybius Square
The Polybius square, also known as the Polybius checkerboard, is a device invented by the ancient Greeks Cleoxenus and Democleitus, and made famous by the historian and scholar Polybius. The device is used for fractionating plaintext characters so that they can be represented by a smaller set of symbols, which is useful for telegraphy, steganography, and cryptography. The device was originally used for fire signalling, allowing for the coded transmission of any message, not just a finite amount of predetermined options as was the convention before. Basic form According to Polybius' ''Histories,'' the device was invented by Cleoxenus and Democleitus, and further developed by Polybius himself. The device partitioned the alphabet into five tablets with five letters each (except for the last one with only four). There are no surviving tablets from antiquity. Letters are represented by two numbers from one to five, allowing the representation of 25 characters using only 5 numeric sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Playfair
The Two-square cipher, also called double Playfair, is a manual symmetric encryption technique. It was developed to ease the cumbersome nature of the large encryption/decryption matrix used in the four-square cipher while still being slightly stronger than the single-square Playfair cipher. The technique encrypts pairs of letters (''digraphs''), and thus falls into a category of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers, which operate on single characters. The use of digraphs makes the two-square technique less susceptible to frequency analysis attacks, as the analysis must be done on 676 possible digraphs rather than just 26 for monographic substitution. The frequency analysis of digraphs is possible, but considerably more difficult, and it generally requires a much larger ciphertext in order to be useful. History Félix Delastelle described the cipher in his 1901 book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Cryptogram Association
The American Cryptogram Association (ACA) is an American non-profit organization devoted to the hobby of cryptography, with an emphasis on types of codes, ciphers, and cryptograms that can be solved either with pencil and paper, or with computers, but not computer-only systems. History The ACA was formed on September 1, 1930. Initially the primary interest was in monoalphabetic substitution ciphers (also known as "single alphabet" or "Aristocrat" puzzles), but this has since extended to dozens of different systems, such as Playfair, autokey, transposition, and Vigenère ciphers. Since some of its members had belonged to the “National Puzzlers' League”, some of the NPL terminology ("nom," "Krewe," etc.) is also used in the ACA. Publications and activities The association has a collection of books and articles o ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambros D
Lambros, also spelled Lampros (Λάμπρος) is Greek masculine first ("Christian") name and surname or family name. Lambros means "shining, bright, radiant". It is related to the nominalized adjective ''Lambri'' (Λαμπρή), meaning the Easter Sunday. As a name it is mostly found in Cyprus, Central Greece and the Peloponnese. People bearing this first name, celebrate their Name day on Easter Sunday. The usual female form is Lambrini (Λαμπρινή). People *Lambros Katsonis *Lambros Choutos * Lambros Koromilas *Lambros Konstantaras * Lambros D. Callimahos * Lambros Koutsonikas * Lambros Tsoumaris As surname: *Spyridon Lambros Spyridon Lambros or Lampros ( el, Σπυρίδων Λάμπρος; 1851–1919) was a Greek history professor and briefly Prime Minister of Greece during the National Schism. Biography He was born in Corfu in 1851 and was educated in London, Paris ... {{given name Greek masculine given names ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in military ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
