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 1/1 // URL: http://world-information.org/wio/infostructure/100437611776/100438659090
Fiber-optic cable networks may become the dominant method for high-speed Internet connections. Since the first fiber-optic cable was laid across the Atlantic in 1988, the demand for faster Internet connections is growing, fuelled by the growing network traffic, partly due to increasing implementation of corporate networks spanning the globe and to the use of graphics-heavy contents on the
Fiber-optic cables have not much more in common with copper wires than the capacity to transmit information. As copper wires, they can be terrestrial and submarine connections, but they allow much higher transmission rates. Copper wires allow 32 telephone calls at the same time, but fiber-optic cable can carry 40,000 calls at the same time. A capacity,
Copper wires will not come out of use in the foreseeable future because of technologies as
For technical information from the Encyclopaedia Britannica on telecommunication cables, click
An entertaining report of the laying of the FLAG submarine cable, up to now the longest fiber-optic cable on earth, including detailed background information on the cable industry and its history, Neal Stephenson has written for Wired: Mother Earth Mother Board. Click
Susan Dumett has written a short history of undersea cables for Pretext magazine, Evolution of a Wired World. Click
A timeline history of submarine cables and a detailed list of seemingly all submarine cables of the world, operational, planned and out of service, can be found on the Web site of the
For maps of fiber-optic cable networks see the website of