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:
TEXTBLOCK 1/2 // URL: http://world-information.org/wio/infostructure/100437611776/100438659090
Since the invention of appropriate means and technologies, communication no longer requires face-to-face meetings.
From writing and reading to using computers, expanding and exhausting one's possibilities to communicate relies more and more on the application of skills we have to learn. With the increasing importance of communication technologies, learning to apply them properly becomes a kind of rite of passage.
A Small World
From the very beginning - the first Sumerian pictographs on clay tablets - to today's state of the art technologies - broadband communication via
Since the invention of the electrical telegraph, but especially with today's growing digital communication networks, every location on earth seems to be close, however distant it may be, and also time no longer remains a significant dimension.
Threatened Cultural Memory
More and more information is transmitted and produced faster and faster, but the shelf life of information becomes more and more fragile. For more than 4500 years Sumerian pictographs written on clay tablets remained intact, but newspapers and books, printed some decades ago, crumble into pieces; film reels, video tapes and cassettes corrode. Digitalization of information is not a cure; on the contrary it even intensifies the danger of destroying cultural heritage. Data increasingly requires specific software and hardware, but to regularly convert all available digitized information is an unexecutable task.
Compared to the longevity of pictographs on clay tablets, digitized information is produced for instant one-time use. The increasing production and processing of information causes a problem hitherto unknown: the loss of our cultural memory.
For further information see
For another history of communication systems see
TEXTBLOCK 2/2 // URL: http://world-information.org/wio/infostructure/100437611796/100438659807
Java applets are small programs that can be sent along with a Web page to a user. Java applets can perform interactive animations, immediate calculations, or other simple tasks without having to send a user request back to the server. They are written in Java, a platform-independent computer language, which was invented by
Source: Whatis.com
The U.S. Data Encryption Standard (= DES) is the most widely used encryption algorithm, especially used for protection of financial transactions. It was developed by IBM in 1971. It is a symmetric-key cryptosystem. The DES algorithm uses a 56-bit encryption key, meaning that there are 72,057,594,037,927,936 possible keys.
for more information see: