Fields are algebraic structures, meant to generalize things like the real or rational numbers, where you have two operations, addition and multiplication, such that the following hold: Addition and multiplication are both commutative and associative operations. Multiplication distributes over addition, i.
Life[ edit ] Al-Kindi was born in Kufa to an aristocratic family of the Kinda tribe, descended from the chieftain al-Ash'ath ibn Qaysa contemporary of Muhammad.
He later went to complete his studies in Baghdad, where he was patronized by the Abbasid caliphs al-Ma'mun ruled — and al-Mu'tasim r.
On account of his learning and aptitude for study, al-Ma'mun appointed him to the House of Wisdoma recently established centre for the translation of Greek philosophical and scientific texts, in Baghdad.
He was also well known for his beautiful calligraphyand at one point was employed as a calligrapher by al-Mutawakkil. Al-Kindi's position would be enhanced under al-Mu'tasim, who appointed him as a tutor to his son.
There are various theories concerning this: Henry CorbinUnderstanding the concept behind cryptography authority on Islamic studies, says that inal-Kindi died "a lonely man", in Baghdad during the reign of al-Mu'tamid r.
Felix Klein-Franke suggests a number of reasons for this: However, he says the most probable cause of this was that his writings never found popularity amongst subsequent influential philosophers such as al-Farabi and Avicennawho ultimately overshadowed him.
Al-Kindi carried out this mission from the House of Wisdom Bayt al-Hikmaan institute of translation and learning patronized by the Abbasid Caliphs, in Baghdad.
Despite this, he did make clear that he believed revelation was a superior source of knowledge to reason because it guaranteed matters of faith that reason could not uncover. And while his philosophical approach was not always original, and was even considered clumsy by later thinkers mainly because he was the first philosopher writing in the Arabic languagehe successfully incorporated Aristotelian and especially neo-Platonist thought into an Islamic philosophical framework.
This was an important factor in the introduction and popularization of Greek philosophy in the Muslim intellectual world. In one of his treatises on the subject, he says that these bodies are rational entities, whose circular motion is in obedience to and worship of God. Their role, al-Kindi believes, is to act as instruments for divine providence.
He furnishes empirical evidence as proof for this assertion; different seasons are marked by particular arrangements of the planets and stars most notably the sun ; the appearance and manner of people varies according to the arrangement of heavenly bodies situated above their homeland.
One theory he posits in his works is from Aristotle, who conceived that the movement of these bodies causes friction in the sub-lunar region, which stirs up the primary elements of earth, fire, air and water, and these combine to produce everything in the material world.
An alternative view found his treatise On Rays is that the planets exercise their influence in straight lines. In each of these, he presents two fundamentally different views of physical interaction; action by contact and action at a distance.
This dichotomy is duplicated in his writings on optics. On the Stellar Rays. Several epistles on weather and meteorology, including De mutatione temporum, "On the Changing of the Weather". Treatise on the Judgement of Eclipses. Treatise on the Dominion of the Arabs and its Duration used to predict the end of Arab rule.
The Choices of Days on elections.
On the Revolutions of the Years on mundane astrology and natal revolutions. Optics[ edit ] Al-Kindi was the first major writer on optics since antiquity. Roger Bacon placed him in the first rank after Ptolemy as a writer on the topic.
Aristotle had believed that in order for the eye to perceive an object, both the eye and the object must be in contact with a transparent medium such as air that is filled with light. When these criteria are met, the "sensible form" of the object is transmitted through the medium to the eye.
On the other hand, Euclid proposed that vision occurred in straight lines when "rays" from the eye reached an illuminated object and were reflected back.Wassenaar Arrangement / COCOM [Sources 1, 5] 1.
Export/ import controls COCOM. COCOM (Coordinating Committee for Multilateral Export Controls) was an international organization for the mutual control of the export of strategic products and technical data from country members to .
Aug 01, · Bitcoin is a digital currency that exists almost wholly in the virtual realm, unlike physical currencies like dollars and euros. A growing number of proponents support its use as an alternative.
7/26 Chapter 10 of Understanding Cryptography by Christof Paar and Jan Pelzl Main idea • For a given message x, a digital signature is appended to the message (just like a conventional signature).
• Only the person with the private key should be able to generate the signature. • The signature must change for every document. ⇒The signature is .
Chapter 2, Public-Key Cryptography, provides a brief, nonmathematical introduction to the concepts of public-key cryptography relevant to the material presented throughout the remainder of the book. It includes the distinction between symmetric and public-key ciphers, the concept of a key pair, the services of this technology, terminology, and.
Hyperlinked definitions and discussions of many terms in cryptography, mathematics, statistics, electronics, patents, logic, and argumentation used in cipher construction, analysis and production. A Ciphers By Ritter page. Understanding the blockchain.
The technology concept behind the blockchain is similar to that of a database, except that the way you interact with that database is different. The combination of cryptography and blockchain technology together ensures there is never a duplicate recording of the same transaction.