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History Of Cryptography
Cryptography, the use of codes and ciphers to protect secrets, began thousands of years ago. Until recent decades, it has been the story of what might be called classical cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids. In the early 20th century, the invention of complex mechanical and electromechanical machines, such as the Enigma rotor machine, provided more sophisticated and efficient means of encryption; and the subsequent introduction of electronics and computing has allowed elaborate schemes of still greater complexity, most of which are entirely unsuited to pen and paper. The development of cryptography has been paralleled by the development of cryptanalysis — the "breaking" of codes and ciphers. The discovery and application, early on, of frequency analysis to the reading of encrypted communications has, on occasion, altered the course of history. Thus the Zimmermann Telegram triggered the United States' en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Cryptography
In cryptography, a classical cipher is a type of cipher that was used historically but for the most part, has fallen into disuse. In contrast to modern cryptographic algorithms, most classical ciphers can be practically computed and solved by hand. However, they are also usually very simple to break with modern technology. The term includes the simple systems used since Greek and Roman times, the elaborate Renaissance ciphers, World War II cryptography such as the Enigma machine and beyond. In contrast, modern strong cryptography relies on new algorithms and computers developed since the 1970s. Types of classical ciphers Classical ciphers are often divided into ''transposition ciphers'' and ''substitution ciphers''. Substitution ciphers In a substitution cipher, letters (or groups of letters) are systematically replaced throughout the message for other letters (or groups of letters). A well-known example of a substitution cipher is the Caesar cipher. To encrypt a message with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hebrew Language
Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved throughout history as the main liturgical language of Judaism (since the Second Temple period) and Samaritanism. Hebrew is the only Canaanite language still spoken today, and serves as the only truly successful example of a dead language that has been revived. It is also one of only two Northwest Semitic languages still in use, with the other being Aramaic. The earliest examples of written Paleo-Hebrew date back to the 10th century BCE. Nearly all of the Hebrew Bible is written in Biblical Hebrew, with much of its present form in the dialect that scholars believe flourished around the 6th century BCE, during the time of the Babylonian captivity. For this reason, Hebrew has been referred to by Jews as '' Lashon Hakodesh'' (, ) since an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steganography
Steganography ( ) is the practice of representing information within another message or physical object, in such a manner that the presence of the information is not evident to human inspection. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. The word ''steganography'' comes from Greek ''steganographia'', which combines the words ''steganós'' (), meaning "covered or concealed", and ''-graphia'' () meaning "writing". The first recorded use of the term was in 1499 by Johannes Trithemius in his '' Steganographia'', a treatise on cryptography and steganography, disguised as a book on magic. Generally, the hidden messages appear to be (or to be part of) something else: images, articles, shopping lists, or some other cover text. For example, the hidden message may be in invisible ink between the visible lines of a private letter. Some implementations of steganography that lack a shared secret are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herodotus
Herodotus ( ; grc, , }; BC) was an ancient Greek historian and geographer from the Greek city of Halicarnassus, part of the Persian Empire (now Bodrum, Turkey) and a later citizen of Thurii in modern Calabria ( Italy). He is known for having written the '' Histories'' – a detailed account of the Greco-Persian Wars. Herodotus was the first writer to perform systematic investigation of historical events. He is referred to as " The Father of History", a title conferred on him by the ancient Roman orator Cicero. The ''Histories'' primarily cover the lives of prominent kings and famous battles such as Marathon, Thermopylae, Artemisium, Salamis, Plataea, and Mycale. His work deviates from the main topics to provide a cultural, ethnographical, geographical, and historiographical background that forms an essential part of the narrative and provides readers with a wellspring of additional information. Herodotus has been criticized for his inclusion of "legends and f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparta
Sparta ( Doric Greek: Σπάρτα, ''Spártā''; Attic Greek: Σπάρτη, ''Spártē'') was a prominent city-state in Laconia, in ancient Greece. In antiquity, the city-state was known as Lacedaemon (, ), while the name Sparta referred to its main settlement on the banks of the Eurotas River in Laconia, in south-eastern Peloponnese. Around 650 BC, it rose to become the dominant military land-power in ancient Greece. Given its military pre-eminence, Sparta was recognized as the leading force of the unified Greek military during the Greco-Persian Wars, in rivalry with the rising naval power of Athens. Sparta was the principal enemy of Athens during the Peloponnesian War (431–404 BC), from which it emerged victorious after the Battle of Aegospotami. The decisive Battle of Leuctra in 371 BC ended the Spartan hegemony, although the city-state maintained its political independence until its forced integration into the Achaean League in 192 BC. The city nevertheless ... [...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] |
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] |
Ancient Greeks
Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of culturally and linguistically related city-states and other territories. Most of these regions were officially unified only once, for 13 years, under Alexander the Great's empire from 336 to 323 BC (though this excludes a number of Greek city-states free from Alexander's jurisdiction in the western Mediterranean, around the Black Sea, Cyprus, and Cyrenaica). In Western history, the era of classical antiquity was immediately followed by the Early Middle Ages and the Byzantine period. Roughly three centuries after the Late Bronze Age collapse of Mycenaean Greece, Greek urban poleis began to form in the 8th century BC, ushering in the Archaic period and the colonization of the Mediterranean Basin. This was followed by the age of Classical Gree ... [...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] |
Greek Magical Papyri
The Greek Magical Papyri (Latin: ''Papyri Graecae Magicae'', abbreviated ''PGM'') is the name given by scholars to a body of papyri from Graeco-Roman Egypt, written mostly in ancient Greek (but also in Old Coptic, Demotic, etc.), which each contain a number of magical spells, formulae, hymns, and rituals. The materials in the papyri date from the 100s BCE to the 400s CE.Hans Dieter Betz (ed), ''The Greek Magical Papyri in translation'', University of Chicago Press, 1985, p.xli. The manuscripts came to light through the antiquities trade, from the 1700s onward. One of the best known of these texts is the Mithras Liturgy. The texts were published in a series, and individual texts are referenced using the abbreviation ''PGM'' plus the volume and item number. Each volume contains a number of spells and rituals. Further discoveries of similar texts from elsewhere have been allocated PGM numbers for convenience. History Production The corpus of the ''PGM'' were not based on an an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demotic (Egyptian)
Demotic (from grc, δημοτικός ''dēmotikós'', 'popular') is the ancient Egyptian script derived from northern forms of hieratic used in the Nile Delta, and the stage of the Egyptian language written in this script, following Late Egyptian and preceding Coptic. The term was first used by the Greek historian Herodotus to distinguish it from hieratic and hieroglyphic scripts. By convention, the word "Demotic" is capitalized in order to distinguish it from demotic Greek. Script The Demotic script was referred to by the Egyptians as ', "document writing," which the second-century scholar Clement of Alexandria called , "letter-writing," while early Western scholars, notably Thomas Young, formerly referred to it as "Enchorial Egyptian." The script was used for more than a thousand years, and during that time a number of developmental stages occurred. It is written and read from right to left, while earlier hieroglyphs could be written from top to bottom, left to right, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kama Sutra
The ''Kama Sutra'' (; sa, कामसूत्र, , ; ) is an ancient Indian Sanskrit text on sexuality, eroticism and emotional fulfillment in life. Attributed to Vātsyāyana, the ''Kama Sutra'' is neither exclusively nor predominantly a sex manual on sex positions, but rather was written as a guide to the art of living well, the nature of love, finding a life partner, maintaining one's love life, and other aspects pertaining to pleasure-oriented faculties of human life. It is a ''sutra''-genre text with terse aphoristic verses that have survived into the modern era with different s (exposition and commentaries). The text is a mix of prose and anustubh-meter poetry verses. The text acknowledges the Hindu concept of Purusharthas, and lists desire, sexuality, and emotional fulfillment as one of the proper goals of life. Its chapters discuss methods for courtship, training in the arts to be socially engaging, finding a partner, flirting, maintaining power in a married life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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