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Scytale
In cryptography, a scytale (; also transliterated skytale, grc, σκυτάλη ''skutálē'' "baton, cylinder", also ''skútalon'') is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message. The ancient Greeks, and the Spartans in particular, are said to have used this cipher to communicate during military campaigns. The recipient uses a rod of the same diameter on which the parchment is wrapped to read the message. To cryptanalyse it is not difficult. Use a tapered cone. Wrap the strip around it. Somewhere plaintext will be visible. That is the diameter of the rods used. Encrypting Suppose the rod allows one to write four letters around in a circle and five letters down the side of it. The plaintext could be: "I am hurt very badly help". To encrypt, one simply writes across the leather: _____________________________________________________________ , , , , , , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transposition Cipher
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] |
Skytale
In cryptography, a scytale (; also transliterated skytale, grc, σκυτάλη ''skutálē'' "baton, cylinder", also ''skútalon'') is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message. The ancient Greeks, and the Spartans in particular, are said to have used this cipher to communicate during military campaigns. The recipient uses a rod of the same diameter on which the parchment is wrapped to read the message. To cryptanalyse it is not difficult. Use a tapered cone. Wrap the strip around it. Somewhere plaintext will be visible. That is the diameter of the rods used. Encrypting Suppose the rod allows one to write four letters around in a circle and five letters down the side of it. The plaintext could be: "I am hurt very badly help". To encrypt, one simply writes across the leather: _____________________________________________________________ , , , , , , ... [...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] |
Classical Ciphers
Classical may refer to: European antiquity *Classical antiquity, a period of history from roughly the 7th or 8th century B.C.E. to the 5th century C.E. centered on the Mediterranean Sea *Classical architecture, architecture derived from Greek and Roman architecture of classical antiquity *Classical mythology, the body of myths from the ancient Greeks and Romans *Classical tradition, the reception of classical Greco-Roman antiquity by later cultures *Classics, study of the language and culture of classical antiquity, particularly its literature *Classicism, a high regard for classical antiquity in the arts Music and arts *Classical ballet, the most formal of the ballet styles *Classical music, a variety of Western musical styles from the 9th century to the present *Classical guitar, a common type of acoustic guitar *Classical Hollywood cinema, a visual and sound style in the American film industry between 1927 and 1963 * Classical Indian dance, various codified art forms whose theo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutarch
Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo in Delphi. He is known primarily for his ''Parallel Lives'', a series of biographies of illustrious Greeks and Romans, and ''Moralia'', a collection of essays and speeches. Upon becoming a Roman citizen, he was possibly named Lucius Mestrius Plutarchus (). Life Early life Plutarch was born to a prominent family in the small town of Chaeronea, about east of Delphi, in the Greek region of Boeotia. His family was long established in the town; his father was named Autobulus and his grandfather was named Lamprias. His name is derived from Pluto (πλοῦτον), an epithet of Hades, and Archos (ἀρχός) meaning "Master", the whole name meaning something like "Whose master is Pluto". His brothers, Timon and Lamprias, are frequently mentioned in his essays and dialogues, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollonius Of Rhodes
Apollonius of Rhodes ( grc, Ἀπολλώνιος Ῥόδιος ''Apollṓnios Rhódios''; la, Apollonius Rhodius; fl. first half of 3rd century BC) was an ancient Greek author, best known for the ''Argonautica'', an epic poem about Jason and the Argonauts and their quest for the Golden Fleece. The poem is one of the few extant examples of the epic genre and it was both innovative and influential, providing Ptolemaic Egypt with a "cultural mnemonic" or national "archive of images", and offering the Latin poets Virgil and Gaius Valerius Flaccus a model for their own epics. His other poems, which survive only in small fragments, concerned the beginnings or foundations of cities, such as Alexandria and Cnidus places of interest to the Ptolemies, whom he served as a scholar and librarian at the Library of Alexandria. A literary dispute with Callimachus, another Alexandrian librarian/poet, is a topic much discussed by modern scholars since it is thought to give some insight into t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archilochus
Archilochus (; grc-gre, Ἀρχίλοχος ''Arkhilokhos''; c. 680 – c. 645 BC) was a Greek lyric poet of the Archaic period from the island of Paros. He is celebrated for his versatile and innovative use of poetic meters, and is the earliest known Greek author to compose almost entirely on the theme of his own emotions and experiences. Biography A considerable amount of information about the life of Archilochus has come down to the modern age via his surviving work, the testimony of other authors, and inscriptions on monuments, yet it all needs to be viewed with caution – the biographical tradition is generally unreliable and the fragmentary nature of the poems does not really support inferences about his personal history. The vivid language and intimate details of the poems often look autobiographical yet it is known, on the authority of Aristotle, that Archilochus sometimes role-played. The philosopher quoted two fragments as examples of an author speaking in somebo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciphertext
In cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher to decrypt it. This process prevents the loss of sensitive information via hacking. Decryption, the inverse of encryption, is the process of turning ciphertext into readable plaintext. Ciphertext is not to be confused with codetext because the latter is a result of a code, not a cipher. Conceptual underpinnings Let m\! be the plaintext message that Alice wants to secretly transmit to Bob and let E_k\! be the encryption cipher, where _k\! is a cryptographic key. Alice must first transform the plaintext into ciphertext, c\!, in order to securely send the message to Bob, as follows: : c = E_k(m). \! In a symmetric-key system, Bob knows Alice's encryption key. Once the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct military uniform. It may consist of one or more military branches such as an army, navy, air force, space force, marines, or coast guard. The main task of the military is usually defined as defence of the state and its interests against external armed threats. In broad usage, the terms ''armed forces'' and ''military'' are often treated as synonymous, although in technical usage a distinction is sometimes made in which a country's armed forces may include both its military and other paramilitary forces. There are various forms of irregular military forces, not belonging to a recognized state; though they share many attributes with regular military forces, they are less often referred to as simply ''military''. A nation's military may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere. In more modern usage, the length d of a diameter is also called the diameter. In this sense one speaks of diameter rather than diameter (which refers to the line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r. :d = 2r \qquad\text\qquad r = \frac. For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the is often defined to be the smallest such distance. Both quantities can be calculated efficiently using rotating calipers. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all ... [...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] |
