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:
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The Net connections can be based on wire-line and wireless access technolgies.
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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
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
Scheduled privatization of intergovernmental satellite consortia:
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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
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Source: Analysys Satellite Communications Database
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Ciphers as well as codes are transmitted openly. Everyone can see that they exist. Not so with steganograms.
Steganography is the art and science of communicating in a way which hides the existence of the secret part in that communication. During the Italian Renaissance and the time of the Elizabethan Age in England cryptography was very popular, for political reasons as well as for amusements (see John Dee).
In literature steganography played an important role. Many steganographs of that period have only been deciphered recently like some of the Shakespearean sonnets, which now seem to proof that the actor William Shakespeare was not the author of the famous poems and dramas, but that the latter' name was, and Francis Bacon, or even Francis Tudor, as some ciphers and other sources talk of him as Queen Elisabeth I.'s secret son.
for further details see:
One kind of steganogram is digital watermarking:
Watermarks protect digital images, videos, but also audio and multimedia products. They are made out of digital signals, put into other digital signals. They try to be invisible on first sight and should be nearly impossible to remove. The process of producing watermarks is to overlay some sort of identifying image over the original image (non-digital watermarks, like on money can be seen by holding the paper against light). Copying the image destroys the watermark, which cannot be copied. Any alteration of the original destroys the watermark, too.
Watermarking is one of the typical inventions of cryptography to assist the biggest content owners, but advertised as something necessary and helpful for everybody. Who in fact gets any advantage out of watermarking? The private user most of the time will not really need it except for small entities of pictures maybe.
But the big enterprises do. There is a tendency to watermark more and more information in the Internet, which until now was considered as free and as a cheap method to receive information. Watermarking could stop this democratic development.
for further information see:
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