As stated, telecommunication is seen as an unreliable media for transporting secret messages. Therefore today, cryptography is needed more than ever before, especially for e-commerce.
Key cryptosystems try to provide more privacy.
symmetric-key cryptosystems:
The same key is used for both encryption and decryption. In this case the encipherer and the recipient of the message/text have to agree on a common key before the enciphering-process can start. And most of all they should trust each other. And exactly this is the main problem of this system: how to exchange the key without offering an opportunity for stealing it?
In former times messengers or pigeons were doing the exchange of those keys.
Symmetric-key systems make sense in small entities. If a lot of people are spread over a wide area and belong to the same network, distributing the keys starts getting complicated.
Today, those cryptosystems get controlled by other keys, based on highly complex mathematical algorithms.
some symmetric-key systems are:
- DES (Data Encryption Standard), the standard for credit cards
- Triple-DES, which is a variation of DES, encrypting the plaintext three times.
- IDEA (International Data Encryption Standard)
- blowfish encryption algorithm, which is said to be faster than DES and IDEA
Security and confidence are the key-words for a popular key-system: As DES and its successors have been used for so many years and by many people without having been broken, they are considered safe - safer than others, not used that frequently, no matter whether they are actually safer or not.
For further information see:
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-1994
Viacom multimedia and industrial corporation takes control of Paramount Communications for US$ 9.6 billion, as well as Blockbuster Entertainment, a huge video store chain, for US$ 8.4. billion.
1995
Entertainment giant Disney buys Capital Cities-ABC for US$ 19 billion.
The industrial and broadcasting company Westinghouse Corp. buys out CBS for US$ 5.4 billion.
In a US$ 7.2 billion deal, Time Warner acquires Turner Communications, owner of prime cable TV channels CNN, TBS and TNT and a major classic American film library.
1996
Westinghouse/CBS buys Infinity Broadcasting's large group of radio stations.
Murdoch and News Corp. acquire ten more TV stations and TV production studios with the US$ 2.5 billion purchase of New World Communications Group.
Viacom buys half of UPN-TV network, adding that to its other holdings, which include eleven TV stations, along with MTV, VH-1, and other cable TV channels and Paramount movie studios.
1997
Radio Groups Chancellor Media and Evergreen merge and are linked by ownership with Capstar Broadcasting; they also buy ten radio stations from Viacom. By mid-1997 Chancellor/Capstar controls no fewer than 325 radio stations around the United States.
Chancellor/Capstar's controlling ownership group, Hicks Muse Tate & Furst, buys the seventh largest radio group, SFX, adding another seventy-two radio stations, making a total of nearly four hundred stations controlled by this one source.
Westinghouse-CBS buys out American Radio Systems, the fourth largest radio chain in total audience, which gives Westinghouse-CBS over 170 radio stations with a total audience nearly equal to that of the Chancellor/Capstar group.
Giant European-based print and electronic publishing and data base corporations Reed Elsevier and Wolters Kluwer merge.
1998
Bertelsmann buys the Random House-Alfred A. Knopf-Crown Publishing group of book publishers from Newhouse/Advance Publications, adding to its Bantam-Doubleday-Dell publishing group and giving Bertelsmann by far the largest English-language publishing operations.
1999
AOL, the worlds leading Internet service provider and Time Warner, the worlds leading classical media company merge in a US$ 243.3 billion deal.
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"All nature is merely a cipher and a secret writing."
Blaise de Vigenère
In the (dis-)information age getting information but at the same time excluding others from it is part of a power-game (keeping the other uneducated). The reason for it eventually has found an argument called security.
Compared to the frequency of its presence in articles, the news and political speeches security seems to be one of the most popular words of the 90's. It must be a long time ago when that word was only used for and by the military and the police. Today one can find it as part of every political issue. Even development assistance and nutrition programs consider it part of its work.
The so-called but also real need for information security is widespread and concerning everybody, whether someone uses information technology or not. In any case information about individuals is moving globally; mostly sensitive information like about bank records, insurance and medical data, credit card transactions, and much much more. Any kind of personal or business communication, including telephone conversations, fax messages, and of course e-mail is concerned. Not to forget further financial transactions and business information. Almost every aspect of modern life is affected.
We want to communicate with everybody - but do not want anybody to know.
Whereas the market already depends on the electronic flow of information and the digital tools get faster and more sophisticated all the time, the rise of privacy and security concerns have to be stated as well.
With the increase of digital communication its vulnerability is increasing just as fast. And there exist two (or three) elements competing and giving the term digital security a rather drastic bitter taste: this is on the one hand the growing possibility for criminals to use modern technology not only to hide their source and work secretly but also to manipulate financial and other transfers. On the other hand there are the governments of many states telling the population that they need access to any kind of data to keep control against those criminals. And finally there are those people, living between enlightening security gaps and at the same time harming other private people's actions with their work: computer hackers.
While the potential of global information is regarded as endless, it is those elements that reduce it.
There is no definite solution, but at least some tools have been developed to improve the situation: cryptography, the freedom to encode those data that one does not want to be known by everybody, and give a possibility to decode them to those who shall know the data.
During the last 80 years cryptography has changed from a mere political into a private, economic but still political tool: at the same time it was necessary to improve the tools, eventually based on mathematics. Hence generally cryptography is regarded as something very complicated. And in many ways this is true as the modern ways of enciphering are all about mathematics.
"Crypto is not mathematics, but crypto can be highly mathematical, crypto can use mathematics, but good crypto can be done without a great reliance on complex mathematics." (W.T. Shaw)
For an introduction into cryptography and the mathematical tasks see:
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It is a system, where letters get converted into numeric characters.
The numbers were not written down and sent but signaled with torches.
for example:
A=1-1
B=1-2
C=1-3
W=5-2
for more information see:
Writing and calculating came into being at about the same time. The first pictographs carved into clay tablets are used for administrative purposes. As an instrument for the administrative bodies of early empires, who began to rely on the collection, storage, processing and transmission of data, the skill of writing was restricted to a few. Being more or less separated tasks, writing and calculating converge in today's computers.
Letters are invented so that we might be able to converse even with the absent, says Saint Augustine. The invention of writing made it possible to transmit and store information. No longer the ear predominates; face-to-face communication becomes more and more obsolete for administration and bureaucracy. Standardization and centralization become the constituents of high culture and vast empires as Sumer and China.
Electronic messages are transmitted and received by computers through a network. By E-Mail texts, images, sounds and videos can be sent to single users or simultaneously to a group of users. Now texts can be sent and read without having them printed.
E-Mail is one of the most popular and important services on the Internet.
The water-clocks are an early long-distance-communication-system. Every communicating party had exactly the same jar, with a same-size-hole that was closed and the same amount of water in it. In the jar was a stick with different messages written on. When one party wanted to tell something to the other it made a fire-sign. When the other answered, both of them opened the hole at the same time. And with the help of another fire-sign closed it again at the same time, too. In the end the water covered the stick until the point of the wanted message.