1960s - 1970s: Expert Systems Gain Attendance The concept of expert systems dates back to the 1960s but first gained prominence in the 1970s. Conclusive for this development were the insights of the Stanford University professor Edward Feigenbaum, who in 1977 demonstrated that the problem-solving capacity of a computer program rather is a result of the knowledge it posses, than of the applied programming techniques and formalisms. Expert systems were designed to mimic the knowledge and reasoning capabilities of a human specialist in a given domain by using (top down) artificial intelligence techniques. Made possible by the large storage capacity of the computers at the time, expert systems had the potential to interpret statistics and formulate rules. An initial use of expert systems was to diagnose and treat human physical disorders, but as its applications in the market place were extensive over the course of the following years they were also employed in fields such as stock market forecast, taxation, chemistry, and geology.

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RSA The best known of the two-key cryptosystems developed in the mid-1980s is the Rivest-Shamir-Adleman (RSA) cryptoalgorithm, which was first published in April, 1977. Since that time, the algorithm has been employed in the most widely-used Internet electronic communications encryption program, Pretty Good Privacy (PGP). It is also employed in both the Netscape Navigator and Microsoft Explorer web browsing programs in their implementations of the Secure Sockets Layer (SSL), and by Mastercard and VISA in the Secure Electronic Transactions (SET) protocol for credit card transactions.

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Optical communication system by Aeneas Tacitus, 4th century B.C. Aeneas Tacitus, a Greek military scientist and cryptographer, invented an optical communication system that combines water and beacon telegraphy. Torches indicated the beginnings and the ends of message transmissions while water jars were used to transmit the messages. These jars had a plugged standard-size hole drilled on the bottom side and were filled with water. As those who sent and those who received the message unplugged the jars simultaneously, the water drained out. Because the transmitted messages corresponded to water levels, the sender indicated by torch signal that the appropriate water level has been reached. It is a disadvantage that the possible messages are restricted to a given code, but as this system was mainly used for military purposes, this was offset by the advantage that it was almost impossible for outsiders to understand these messages unless they possessed the codebook. With communication separated from transportation, the distant became near. Tacitus' telegraph system was very fast and not excelled until the end of the 18th century. For further information see Joanne Chang & Anna Soellner, Decoding Device, http://www.smith.edu/hsc/museum/ancient_inventions/decoder2.html http://www.smith.edu/hsc/museum/ancient_inven...

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