Acessing the Internet
The Net connections can be based on wire-line and wireless access technolgies.
Usually several kinds of network connections are employed at once. Generally speaking, when an E-mail message is sent it travels from the user's computer via copper wires or coaxial cables  ISDN lines, etc., to an Internet Service Provider, from there, via fibre-optic cables, to the nearest Internet exchange, and on into a backbone network, tunneling across the continent und diving through submarine fibre-optic cables across the Atlantic to another Internet exchange, from there, via another backbone network and across another regional network to the Internet Service Provider of the supposed message recipient, from there via cables and wires of different bandwidth arriving at its destination, a workstation permanently connected to the Internet. Finally a sound or flashing icon informs your virtual neighbor that a new message has arrived.
Satellite communication
Although facing competition from fiber-optic cables as cost-effective solutions for broadband data transmission services, the space industry is gaining increasing importance in global communications. As computing, telephony, and audiovisual technologies converge, new wireless technologies are rapidly deployed occupying an increasing market share and accelerating the construction of high-speed networks.
Privatization of satellite communication
Until recently transnational satellite communication was provided exclusively by intergovernmental organizations as Intelsat, Intersputnik and Inmarsat.
Scheduled privatization of intergovernmental satellite consortia:
Satellite consortia
| Year of foundation
| Members
| Scheduled date for privatization
| Intelsat
| 1964
| 200 nations under the leadership of the USA
| 2001
| Intersputnik
| 1971
| 23 nations under the leadership of Russia
| ?
| Inmarsat
| 1979
| 158 nations (all members of the International Maritime Organization)
| privatized since 1999
| Eutelsat
| 1985
| Nearly 50 European nations
| 2001
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When Intelsat began to accumulate losses because of management failures and the increasing market share of fiber-optic cables, this organizational scheme came under attack. Lead by the USA, the Western industrialized countries successfully pressed for the privatization of all satellite consortia they are members of and for competition by private carriers.
As of February 2000, there are 2680 satellites in service. Within the next four years a few hundred will be added by the new private satellite systems. Most of these systems will be so-called Low Earth Orbit satellite systems, which are capable of providing global mobile data services on a high-speed level at low cost.
Because of such technological improvements and increasing competition, experts expect satellite-based broadband communication to be as common, cheap, and ubiquitous as satellite TV today within the next five or ten years.
Major satellite communication projects
Project name
| Main investors
| Expected cost
| Number of satellites
| Date of service start-up
| Astrolink
| Lockheed Martin, TRW, Telespazio, Liberty Media Group
| US$ 3.6 billion
| 9
| 2003
| Globalstar
| 13 investors including Loral Space & Communications, Qualcomm, Hyundai, Alcatel, France Telecom, China Telecom, Daimler Benz and Vodafone/Airtouch
| US$ 3.26 billion
| 48
| 1998
| ICO
| 57 investors including British Telecom, Deutsche Telecom, Inmarsat, TRW and Telefonica
| US$ 4.5 billion
| 10
| 2001
| Skybridge
| 9 investors including Alcatel Space, Loral Space & Communications, Toshiba, Mitsubishi and Sharp
| US$ 6.7 billion
| 80
| 2002
| Teledesic
| Bill Gates, Craig McCaw, Prince Alwaleed Bin Talal Bin Abdul Aziz Alsaud, Abu Dhabi Investment Company
| US$ 9 billion
| 288
| 2004
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Source: Analysys Satellite Communications Database
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Problems of Copyright Management and Control Technologies
Profiling and Data Mining
At their most basic copyright management and control technologies might simply be used to provide pricing information, negotiate the purchase transaction, and release a copy of a work for downloading to the customer's computer. Still, from a technological point of view, such systems also have the capacity to be employed for digital monitoring. Copyright owners could for example use the transaction records generated by their copyright management systems to learn more about their customers. Profiles, in their crudest form consisting of basic demographic information, about the purchasers of copyrighted material might be created. Moreover copyright owners could use search agents or complex data mining techniques to gather more information about their customers that could either be used to market other works or being sold to third parties.
Fair Use
Through the widespread use of copyright management and control systems the balance of control could excessively be shifted in favor of the owners of intellectual property. The currently by copyright law supported practice of fair use might potentially be restricted or even eliminated. While information in analogue form can easily be reproduced, the protection of digital works through copyright management systems might complicate or make impossible the copying of material for purposes, which are explicitly exempt under the doctrine of fair use.
Provisions concerning technological protection measures and fair use are stated in the DMCA, which provides that "Since copying of a work may be a fair use under appropriate circumstances, section 1201 does not prohibit the act of circumventing a technological measure that prevents copying. By contrast, since the fair use doctrine is not a defense e to the act of gaining unauthorized access to a work, the act of circumventing a technological measure in order to gain access is prohibited." Also the proposed EU Directive on copyright and related rights in the information society contains similar clauses. It distinguishes between the circumvention of technical protection systems for lawful purposes (fair use) and the circumvention to infringe copyright. Yet besides a still existing lack of legal clarity also very practical problems arise. Even if the circumvention of technological protection measures under fair use is allowed, how will an average user without specialized technological know-how be able to gain access or make a copy of a work? Will the producers of copyright management and control systems provide fair use versions that permit the reproduction of copyrighted material? Or will users only be able to access and copy works if they hold a digital "fair use license" ("fair use licenses" have been proposed by Mark Stefik, whereby holders of such licenses could exercise some limited "permissions" to use a digital work without a fee)?
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Timeline Cryptography - Introduction
Besides oral conversations and written language many other ways of information-transport are known: like the bush telegraph, drums, smoke signals etc. Those methods are not cryptography, still they need en- and decoding, which means that the history of language, the history of communication and the history of cryptography are closely connected to each other
The timeline gives an insight into the endless fight between enciphering and deciphering. The reasons for them can be found in public and private issues at the same time, though mostly connected to military maneuvers and/or political tasks.
One of the most important researchers on Cryptography through the centuries is David Kahn; many parts of the following timeline are originating from his work.
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Expert system
Expert systems are advanced computer programs that mimic the knowledge and reasoning capabilities of an expert in a particular discipline. Their creators strive to clone the expertise of one or several human specialists to develop a tool that can be used by the layman to solve difficult or ambiguous problems. Expert systems differ from conventional computer programs as they combine facts with rules that state relations between the facts to achieve a crude form of reasoning analogous to artificial intelligence. The three main elements of expert systems are: (1) an interface which allows interaction between the system and the user, (2) a database (also called the knowledge base) which consists of axioms and rules, and (3) the inference engine, a computer program that executes the inference-making process. The disadvantage of rule-based expert systems is that they cannot handle unanticipated events, as every condition that may be encountered must be described by a rule. They also remain limited to narrow problem domains such as troubleshooting malfunctioning equipment or medical image interpretation, but still have the advantage of being much lower in costs compared with paying an expert or a team of specialists.
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 INDEXCARD, 1/3
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atbash
Atbash is regarded as the simplest way of encryption. It is nothing else than a reverse-alphabet. a=z, b= y, c=x and so on. Many different nations used it in the early times of writing.
for further explanations see:
 http://www.ftech.net/~monark/crypto/crypt/atbash.htm
 http://www.ftech.net/~monark/crypto/crypt/atb...
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INDEXCARD, 2/3
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Internet Relay Chat (IRC)
IRC is a text-based chat system used for live discussions of groups.
For a history of IRC see Charles A. Gimon, IRC: The Net in Realtime, http://www.skypoint.com/~gimonca/irc2.html
http://www.skypoint.com/~gimonca/irc2.html
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INDEXCARD, 3/3
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