Cryptography 
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Παρασκευή, 27 Μάρτιος 2015 23:24  
Cryptography (or cryptology; from Greek κρυπτός kryptós, "hidden, secret"; and γράφειν graphein, "writing", or λογία logia, "study", respectively) is the practice and study of techniques for secure communication in the presence of third parties (called adversaries). More generally, it is about constructing and analyzing protocols that block adversaries; various aspects in information security such as data confidentiality, data integrity, authentication, and nonrepudiation are central to modern cryptography. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, and electrical engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce. Cryptography prior to the modern age was effectively synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The originator of an encrypted message shared the decoding technique needed to recover the original information only with intended recipients, thereby precluding unwanted persons from doing do the same. Since World War I and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application more widespread. Modern cryptography is heavily based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in practice by any adversary. It is theoretically possible to break such a system, but it is infeasible to do so by any known practical means. These schemes are therefore termed computationally secure; theoretical advances, e.g., improvements in integer factorization algorithms, and faster computing technology require these solutions to be continually adapted. There exist informationtheoretically secure schemes that provably cannot be broken even with unlimited computing power—an example is the onetime pad—but these schemes are more difficult to implement than the best theoretically breakable but computationally secure mechanisms. [wiki] One very interesting domain for innovative applications is cryptography because this domain combines some of the most interesting issues of mathematics, computer science and electrical engineering. For example, by using model M3 (1939) of Enigma cipher machine, I could send to some of my friends, encrypted, one of the saddest lessons of history*. For the encryption, I have used the following settings: Cipher machine: Enigma
MYXKAIDOFBLBVGQAJYVMRGARPCDOQW Note 1: the photo was found here.


Τελευταία Ενημέρωση στις Σάββατο, 28 Μάρτιος 2015 12:02 