|
History Of Cryptography
Cryptography, the use of codes and ciphers, 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' entry into World War ... [...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'', but there are also ''Null cipher, concealment ciphers''. Substitution ciphers In a substitution cipher, letters, or groups of letters, are systematically replaced throughout the message for other letters, groups of letters, or symbols. A well-known example of a sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hebrew Language
Hebrew (; ''ʿÎbrit'') is a Northwest Semitic language within the Afroasiatic language family. A regional dialect of the Canaanite languages, it was natively spoken by the Israelites and remained in regular use as a first language until after 200 CE and as the liturgical language of Judaism (since the Second Temple period) and Samaritanism. The language was revived as a spoken language in the 19th century, and is the only successful large-scale example of linguistic revival. It is the only Canaanite language, as well as one of only two Northwest Semitic languages, with the other being Aramaic, still spoken today. 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 '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polybius
Polybius (; , ; ) was a Greek historian of the middle Hellenistic period. He is noted for his work , a universal history documenting the rise of Rome in the Mediterranean in the third and second centuries BC. It covered the period of 264–146 BC, recording in detail events in Italy, Iberia, Greece, Macedonia, Syria, Egypt and Africa, and documented the Punic Wars and Macedonian Wars among many others. Polybius' ''Histories'' is important not only for being the only Hellenistic historical work to survive in any substantial form, but also for its analysis of constitutional change and the mixed constitution. Polybius' discussion of the separation of powers in government, of checks and balances to limit power, and his introduction of "the people", all influenced Montesquieu's '' The Spirit of the Laws'', John Locke's '' Two Treatises of Government'', and the framers of the United States Constitution. The leading expert on Polybius for nearly a century was F. W. Walbank (1909 ... [...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 concealed information would not be evident to an unsuspecting person's examination. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. 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 formal shared secret are forms of security through obscurity, while key-dependent steganographic schemes try to adhere to Kerckhoffs's principle. The word ''steganography'' comes from Greek ''steganographia'', which combines the words ''steganós'' (), meaning "covered or concealed", and ''-graphia'' () meaning "writing". The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herodotus
Herodotus (; BC) was a Greek historian and geographer from the Greek city of Halicarnassus (now Bodrum, Turkey), under Persian control in the 5th century BC, and a later citizen of Thurii in modern Calabria, Italy. He wrote the '' Histories'', a detailed account of the Greco-Persian Wars, among other subjects such as the rise of the Achaemenid dynasty of Cyrus. He has been described as " The Father of History", a title conferred on him by the ancient Roman orator Cicero, and the " Father of Lies" by others. 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 was criticized in his times for his inclusion of "legends an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sparta
Sparta 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 in the Evrotas Valley, valley of Evrotas (river), Evrotas river in Laconia, in southeastern Peloponnese. Around 650 BC, it rose to become the dominant military land-power in ancient Greece. 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 Classical Athens, Athens. Sparta was the principal enemy of History of Athens, Athens during the Peloponnesian War (431–404 BC), from which it emerged victorious after the Battle of Aegospotami. The decisive Battle of Leuctra against Thebes, Greece, Thebes in 371 BC ended the Spartan hegemony, although the city-state maintained its Independence, political independence until its forced integration into the Achaean League in 192 BC. The city nevertheless recovered m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transposition Cipher
In cryptography, a transposition cipher (also known as a permutation 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 cipher, 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 (cryptography), key, scrambling the order of characters like the shuffled pieces of a jigsaw puzzle. The resulting m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scytale
In cryptography, a scytale (; also transliterated skytale, ''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 Sparta Sparta 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 in the Evrotas Valley, valley of Evrotas (river), Evrotas rive ...ns 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. 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 () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically related city-states and communities. Prior to the Roman period, most of these regions were officially unified only once under the Kingdom of Macedon from 338 to 323 BC. In Western history, the era of classical antiquity was immediately followed by the Early Middle Ages and the Byzantine period. Three centuries after the decline of Mycenaean Greece during the Bronze Age collapse, 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 Greece, from the Greco-Persian Wars to the death of Alexander the Great in 323 BC, and which included the Golden Age of Athens and the Peloponnesian War. The unificati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), adversarial behavior. More generally, cryptography is about constructing and analyzing Communication protocol, 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 (confidentiality, data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, Smart card#EMV, chip-based payment cards, digital currencies, password, computer passwords, and military communications. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demotic (Egyptian)
Demotic (from ''dēmotikós'', 'popular') is the ancient Egyptian script derived from northern forms of hieratic used in the Nile Delta. The term was first used by the Greek historian Herodotus to distinguish it from hieratic and Egyptian hieroglyphs, 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 (scientist), Thomas Young, formerly referred to it as "wikt:enchorial, 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 right to left. Parts of the Demotic Greek Magical Papyri were written with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
