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
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:
TEXTBLOCK 2/2 // URL: http://world-information.org/wio/infostructure/100437611776/100438659015
The transformation of writings from scrolls to codices, in basic the hardcover book as we know it today, is an essential event in European history. Quoting accurately by page number, browsing through pages and skipping chapters, all impossible while reading scrolls, become possible.
In the computer age we are witnesses to a kind of revival of the scrolls as we scroll upwards and downwards a document we just see a portion of. Maybe the introduction of hypertext is the beginning of a similar change as the replacement of scrolls by codices.
This book gives a fascinating glimpse of the many documented attempts throughout history to develop effective means for long distance communications. Large-scale communication networks are not a twentieth-century phenomenon. The oldest attempts date back to millennia before Christ and include ingenious uses of homing pigeons, mirrors, flags, torches, and beacons. The first true nationwide data networks, however, were being built almost two hundred years ago. At the turn of the 18th century, well before the electromagnetic telegraph was invented, many countries in Europe already had fully operational data communications systems with altogether close to one thousand network stations. The book shows how the so-called information revolution started in 1794, with the design and construction of the first true telegraph network in France, Chappe's fixed optical network.
http://www.it.kth.se/docs/early_net/