Here the keys for encryption and decryption differ. There needs to exist a private key, which is only known to the individual, and a public key, which is published. Every person has her or his own private key that is never published. It is used for decrypting only. Mathematically the different keys are linked to each other, still it is nearly impossible to derive the private key from the public one.
For sending a message to someone, one has to look up the other's public key and encrypt the message with it. The keyholder will use his/her private key to decrypt it. While everybody can send a message with the public key, the private key absolutely has to stay secret - and probably will.
"The best system is to use a simple, well understood algorithm which relies on the security of a key rather than the algorithm itself. This means if anybody steals a key, you could just roll another and they have to start all over." (Andrew Carol)
very famous examples for public-key systems are:
· RSA:
The RSA is probably one of the most popular public-key cryptosystems. With the help of RSA, messages can be encrypted, but also digital signatures are provided.
The mathematics behind are supposedly quite easy to understand (see:
· PGP:
PGP is a public key encryption program. Most of all it is used for e-mail encryption.
It is supposed to be quite safe - until now.
· PGPi is simply the international variation of PGP.
for further information about the RSA and other key-systems visit the RSA homepage:
or:
All of those tools, like hash functions, too, can help to enhance security and prevent crime.
They can theoretically, but sometimes they do not, as the example of the published credit card key of France in March 2000 showed.
For more information see:
Still, cryptography can help privacy.
On the other hand cryptography is only one element to assure safe transport of data. It is especially the persons using it who have to pay attention. A key that is told to others or a lost cryptographic key are the end of secrecy.
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The public relations industry, the same as advertising, is concentrated in the hands of few dominant firms. Still, the striking element about corporate public relations is that PR firms are tightly related to advertising companies. Nine out of the ten biggest international PR agencies have close ties with the advertising industry. Also, looking at the largest acquisitions involving U.S. PR firms from 1997 to 1999 it is apparent that money coming from advertising agencies has played an important role.
Table: Top 10 PR Firms 1998
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With many PR agencies sold to advertising companies, the advertising industry's influence further increases; enabling them to offer their clients not only advertising services, but also know-how in marketing, public opinion, crisis and issues management and political lobbying.
Table: Acquisition of PR Agencies (1997 - 1999)
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Source: Odwyerpr.com.
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The WAP (Wireless Application Protocol) is a specification for a set of communication protocols to standardize the way that wireless devices, such as cellular telephones and radio transceivers, can be used for Internet access, including
While Internet access has been possible in the past, different manufacturers have used different technologies. In the future, devices and service systems that use WAP will be able to interoperate.
Source: Whatis.com
Immanuel Wallerstein (* 1930) is director of the Fernand Braudel Center for the Study of Economies, Historical Systems, and Civilizations. He is one of the most famous sociologists in the Western World. With his book The Modern World-System: Capitalist Agriculture and the Origins of the European World-Economy in the Sixteenth Century (1976), which led to the expression World-System Theory about centers, peripheries and semi-peripheries in the capitalist world system, he did not only influence a whole generation of scientists, but this theory seems to get popular again, due to globalization.