1900 - 2000 A.D. 1904 First broadcast talk 1918 Invention of the short-wave radio 1929 Invention of television in Germany and Russia 1941 Invention of microwave transmission 1946 Long-distance coaxial cable systems and mobile telephone services are introduced in the USA. 1957 Sputnik, the first satellite, is launched by the USSR First data transmissions over regular phone circuits. At the beginning of the story of today's global data networks is the story of the development of satellite communication. In 1955 President Eisenhower announced the USA's intention to launch a satellite. But it in the end it was the Soviet Union, which launched the first satellite in 1957: Sputnik I. After Sputnik's launch it became evident that the Cold War was also a race for leadership in the application of state-of-the-art technology to defense. As the US Department of Defense encouraged the formation of high-tech companies, it laid the ground to Silicon Valley, the hot spot of the world's computer industry. The same year as the USA launched their first satellite - Explorer I - data was transmitted over regular phone circuits for the first time, thus laying the ground for today's global data networks. Today's satellites may record weather data, scan the planet with powerful cameras, offer global positioning and monitoring services, and relay high-speed data transmissions. Yet up to now, most satellites are designed for military purposes such as reconnaissance. 1969 ARPAnet online ARPAnet was the small network of individual computers connected by leased lines that marked the beginning of today's global data networks. An experimental network it mainly served the purpose of testing the feasibility of wide area networks and the possibility of remote computing. It was created for resource sharing between research institutions and not for messaging services like E-mail. Although US military sponsored its research, ARPAnet was not designed for directly martial use but to support military-related research. In 1969 ARPANET went online and linked the first two computers, one located at the University of California, Los Angeles, the other at the Stanford Research Institute. Yet ARPAnet did not become widely accepted before it was demonstrated in action to a public of computer experts at the First International Conference on Computers and Communication in Washington, D. C. in 1972. Before it was decommissioned in 1990, NSFnet, a network of scientific and academic computers funded by the National Science Foundation, and a separate new military network went online in 1986. In 1988 the first private Internet service providers started offering access to NSFnet to a general public. After having become the backbone of the Internet in the USA, in 1995 NSFnet was turned into a consortium of commercial backbone providers. This and the launch of the World Wide Web added to the success of the global data network we call the Net. In the USA it was already in 1994 that commercial users outnumbered military and academic users. Despite the rapid growth of the Net, most computers linked to it are still located in the United States. 1971 Invention of E-Mail 1979 Introduction of fiber-optic cable systems 1992 Launch of the World Wide Web

TEXTBLOCK 1/2 // URL: http://world-information.org/wio/infostructure/100437611796/100438659828

Digital Signatures, Timestamps etc Most computer systems are far from being secure. A lack of security - it is said - might hinder the developments of new information technologies. Everybody knows electronic transactions involve a more or less calculated risk. Rumors about insecurity let consumers doubt whether the commodity of e-commerce is bigger or its risks. First of all the market depends on the consumer's confidence. To provide that another application for public key cryptography gets essential: the digital signature, which is used to verify the authenticity of the sender of certain data. It is done with a special private key, and the public key is verifying the signature. This is especially important if the involved parties do not know one another. The DSA (= Digital Signature Algorithm) is a public-key system which is only able to sign digitally, not to encrypt messages. In fact digital signature is the main-tool of cryptography in the private sector. Digital signatures need to be given for safe electronic payment. It is a way to protect the confidentiality of the sent data, which of course could be provided by other ways of cryptography as well. Other security methods in this respect are still in development, like digital money (similar to credit cards or checks) or digital cash, a system that wants to be anonymous like cash, an idea not favored by governments as it provides many opportunities for money laundry and illegal transactions. If intellectual property needs to be protected, a digital signature, together with a digital timestamp is regarded as an efficient tool. In this context, the difference between identification and authentication is essential. In this context smartcards and firewalls are relevant, too. A lot of digital transactions demand for passwords. More reliable for authentication are biometric identifiers, full of individual and unrepeatable codes, signatures that can hardly be forged. For more terms of cryptography and more information see: http://poseidon.csd.auth.gr/signatures http://www.dlib.org/dlib/december97/ibm/12lotspiech.html http://www.cryptography.com/technology/technology.html http://www.cdt.org/crypto/glossary.shtml http://www.oecd.org//dsti/sti/it/secur/prod/GD97-204.htm

TEXTBLOCK 2/2 // URL: http://world-information.org/wio/infostructure/100437611776/100438659015