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Ibn Adlan
ʻAfīf al-Dīn ʻAlī ibn ʻAdlān al-Mawsilī ( ar, عفيف لدين علي بن عدلان الموصلي ; 1187–1268 CE), born in Mosul, was an Arab cryptologist, linguist and poet who is known for his early contributions to cryptanalysis, to which he dedicated at least two books. He was also involved in literature and poetry, and taught on the Arabic language at the Al-Salihiyya Mosque of Cairo. He was in contact with various rulers of his time, and in this capacity he gained practical experience in cryptanalysis or the science of breaking encoded messages. He dedicated ''On Cryptanalysis,'' his only surviving work on the topic'','' to Al-Ashraf Musa (), the Ayyubid Emir of Damascus. He wrote three other books, including ''Al-Mu'lam'' (''The Told ook'), also on cryptanalysis, but it is now lost. ''On Cryptanalysis'' is a sort of guidebook for cryptanalysts, containing twenty sets of techniques he calls "rules". The methods contains more practical details than Al-Kindi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosul
Mosul ( ar, الموصل, al-Mawṣil, ku, مووسڵ, translit=Mûsil, Turkish: ''Musul'', syr, ܡܘܨܠ, Māwṣil) is a major city in northern Iraq, serving as the capital of Nineveh Governorate. The city is considered the second largest city in Iraq in terms of population and area after the capital Baghdad, with a population of over 3.7 million. Mosul is approximately north of Baghdad on the Tigris river. The Mosul metropolitan area has grown from the old city on the western side to encompass substantial areas on both the "Left Bank" (east side) and the "Right Bank" (west side), as locals call the two riverbanks. Mosul encloses the ruins of the ancient Assyrian city of Nineveh on its east side. Mosul and its surroundings have an ethnically and religiously diverse population; a large majority of its population are Arabs, with Assyrians, Turkmens, and Kurds, and other, smaller ethnic minorities comprising the rest of the city's population. Sunni Islam is the largest r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hijri Year
The Hijri year ( ar, سَنة هِجْريّة) or era ( ''at-taqwīm al-hijrī'') is the era used in the Islamic lunar calendar. It begins its count from the Islamic New Year in which Muhammad and his followers migrated from Mecca to Yathrib (now Medina). This event, known as the Hijrah, is commemorated in Islam for its role in the founding of the first Muslim community (''ummah''). In the West, this era is most commonly denoted as AH ( la, Anno Hegirae , 'in the year of the Hijra') in parallel with the Christian (AD), Common (CE) and Jewish eras (AM) and can similarly be placed before or after the date. In predominantly Muslim countries, it is also commonly abbreviated H ("Hijra") from its Arabic abbreviation '' hāʾ'' (). Years prior to AH 1 are reckoned in English as BH ("Before the Hijrah"), which should follow the date. A year in the Islamic lunar calendar consists of twelve lunar months and has only 354 or 355 days in its year. Consequently its New Year's Day occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arms Race
An arms race occurs when two or more groups compete in military superiority. It consists of a competition between two or more states to have superior armed forces; a competition concerning production of weapons, the growth of a military, and the aim of superior military technology, the term is also used to describe any long-term escalating competitive situation where each competitor or competitive group focuses on out-doing others. Unlike a sporting race, which constitutes a specific event with winning interpretable as the outcome of a singular project, arms races constitute spiralling systems of on-going and potentially open-ended behavior. The existing scholarly literature is divided as to whether arms races correlate with war. International-relations scholars explain arms races in terms of the security dilemma, rationalist spiral models, states with revisionist aims, and deterrence models. Examples Pre-First World War naval arms race From 1897 to 1914, a nav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space (punctuation)
In writing, a space () is a blank area that separates words, sentences, syllables (in syllabification) and other written or printed glyphs (characters). Conventions for spacing vary among languages, and in some languages the spacing rules are complex. Inter-word spaces ease the reader's task of identifying words, and avoid outright ambiguities such as "now here" vs. "nowhere". They also provide convenient guides for where a human or program may start new lines. Typesetting can use spaces of varying widths, just as it can use graphic characters of varying widths. Unlike graphic characters, typeset spaces are commonly stretched in order to align text. The typewriter, on the other hand, typically has only one width for all characters, including spaces. Following widespread acceptance of the typewriter, some typewriter conventions influenced typography and the design of printed works. Computer representation of text facilitates getting around mechanical and physical limitations su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Substitution
In cryptography, a substitution cipher is a method of encrypting in which units of plaintext are replaced with the ciphertext, in a defined manner, with the help of a key; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing the inverse substitution process to extract the original message. Substitution ciphers can be compared with transposition ciphers. In a transposition cipher, the units of the plaintext are rearranged in a different and usually quite complex order, but the units themselves are left unchanged. By contrast, in a substitution cipher, the units of the plaintext are retained in the same sequence in the ciphertext, but the units themselves are altered. There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ibn Al-Durayhim
ʿAlī ibn Muḥammad Ibn al-Durayhim ( ar, علي بن محمد ابن الدريهم; 1312–1359/62 CE) was an Arab cryptologist who gave detailed descriptions of eight cipher systems that discussed substitution ciphers, leading to the earliest suggestion of a "tableau" of the kind that two centuries later became known as the " Vigenère table". His book entitled ''Clear Chapters Goals and Solving Ciphers'' (مقاصد الفصول المترجمة عن حل الترجمة) was recently discovered, but has yet to be published. It includes the use of the statistical techniques pioneered by Al-Kindi and Ibn 'Adlan ʻAfīf al-Dīn ʻAlī ibn ʻAdlān al-Mawsilī ( ar, عفيف لدين علي بن عدلان الموصلي ; 1187–1268 CE), born in Mosul, was an Arab cryptologist, linguist and poet who is known for his early contributions to cryptanalysi .... References {{DEFAULTSORT:Ibn al-Durayhim 1312 births 14th-century deaths Pre-19th-century cryptographers Mathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cour Mosquee Suleymaniye Istanbul
Cour is a surname. Notable people with the name include: *Ajeet Cour (born 1934), Indian writer *Glenys Cour (born 1924), Welsh artist *Pierre Cour (1924–1995), French songwriter See also * Coursera (NYSE: COUR), American online education company * * Cours (other) * La Cour La Cour is a French-language surname meaning "the court". People with this surname include: *Ask la Cour, Danish ballet dancer * Emil La Cour (born 1991), Danish footballer *Janus la Cour (1837–1909), Danish painter * Lise la Cour (1944–2016), D ..., a surname * De la Cour, a surname {{surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Analysis
In cryptanalysis, frequency analysis (also known as counting letters) is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers. Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters occur with varying frequencies. Moreover, there is a characteristic distribution of letters that is roughly the same for almost all samples of that language. For instance, given a section of English language, , , and are the most common, while , , and are rare. Likewise, , , , and are the most common pairs of letters (termed ''bigrams'' or ''digraphs''), and , , , and are the most common repeats. The nonsense phrase " ETAOIN SHRDLU" represents the 12 most frequent letters in typical English language text. In some ciphers, such properties of the natural language plaintext are preserved in the ciphertext, and these patterns have the pote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spread Of Islam
The spread of Islam spans about 1,400 years. Muslim conquests following Muhammad's death led to the creation of the caliphates, occupying a vast geographical area; conversion to Islam was boosted by Arab Muslim forces conquering vast territories and building imperial structures over time. Most of the significant expansion occurred during the reign of the Rashidun from 632 to 661 CE, which was the reign of the first four successors of Muhammad. These early caliphates, coupled with Muslim economics and trading, the Islamic Golden Age, and the age of the Islamic gunpowder empires, resulted in Islam's spread outwards from Mecca towards the Indian, Atlantic, and Pacific Oceans and the creation of the Muslim world. Trade played an important role in the spread of Islam in several parts of the world, especially Indian traders in Southeast Asia.Berkey, pg. 101-102 Muslim dynasties were soon established and subsequent empires such as those of the Umayyads, Abbasids, Mamluks, Seljukids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient History
Ancient history is a time period from the beginning of writing and recorded human history to as far as late antiquity. The span of recorded history is roughly 5,000 years, beginning with the Sumerian cuneiform script. Ancient history covers all continents inhabited by humans in the period 3000 BCAD 500. The three-age system periodizes ancient history into the Stone Age, the Bronze Age, and the Iron Age, with recorded history generally considered to begin with the Bronze Age. The start and end of the three ages varies between world regions. In many regions the Bronze Age is generally considered to begin a few centuries prior to 3000 BC, while the end of the Iron Age varies from the early first millennium BC in some regions to the late first millennium AD in others. During the time period of ancient history, the world population was already exponentially increasing due to the Neolithic Revolution, which was in full progress. While in 10,000 BC, the world population stood at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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