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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"All nature is merely a cipher and a secret writing."
Blaise de Vigenère
In the (dis-)information age getting information but at the same time excluding others from it is part of a power-game (keeping the other uneducated). The reason for it eventually has found an argument called security.
Compared to the frequency of its presence in articles, the news and political speeches security seems to be one of the most popular words of the 90's. It must be a long time ago when that word was only used for and by the military and the police. Today one can find it as part of every political issue. Even development assistance and nutrition programs consider it part of its work.
The so-called but also real need for information security is widespread and concerning everybody, whether someone uses information technology or not. In any case information about individuals is moving globally; mostly sensitive information like about bank records, insurance and medical data, credit card transactions, and much much more. Any kind of personal or business communication, including telephone conversations, fax messages, and of course e-mail is concerned. Not to forget further financial transactions and business information. Almost every aspect of modern life is affected.
We want to communicate with everybody - but do not want anybody to know.
Whereas the market already depends on the electronic flow of information and the digital tools get faster and more sophisticated all the time, the rise of privacy and security concerns have to be stated as well.
With the increase of digital communication its vulnerability is increasing just as fast. And there exist two (or three) elements competing and giving the term digital security a rather drastic bitter taste: this is on the one hand the growing possibility for criminals to use modern technology not only to hide their source and work secretly but also to manipulate financial and other transfers. On the other hand there are the governments of many states telling the population that they need access to any kind of data to keep control against those criminals. And finally there are those people, living between enlightening security gaps and at the same time harming other private people's actions with their work: computer hackers.
While the potential of global information is regarded as endless, it is those elements that reduce it.
There is no definite solution, but at least some tools have been developed to improve the situation: cryptography, the freedom to encode those data that one does not want to be known by everybody, and give a possibility to decode them to those who shall know the data.
During the last 80 years cryptography has changed from a mere political into a private, economic but still political tool: at the same time it was necessary to improve the tools, eventually based on mathematics. Hence generally cryptography is regarded as something very complicated. And in many ways this is true as the modern ways of enciphering are all about mathematics.
"Crypto is not mathematics, but crypto can be highly mathematical, crypto can use mathematics, but good crypto can be done without a great reliance on complex mathematics." (W.T. Shaw)
For an introduction into cryptography and the mathematical tasks see:
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Gutenberg's printing press, an innovative aggregation of inventions known for centuries before Gutenberg: the olive oil press, oil-based ink, block-print technology, and movable types, allowed the mass production of the movable type used to reproduce a page of text and increased the production rate enormously. During the Middle Ages monks took at least a year over making a handwriting copy of a book. Gutenberg printed about 300 sheets per day. Because parchment was too costly for mass production - often for the production of one copy of a medieval book a whole flock of sheep was used - it was substituted by cheap paper made from recycled clothing left over from the massive number of dead caused by the Great Plague.
Within forty-five years, in 1500, already ten million copies were available for a few hundred thousand literate. Because individuals could examine a range of opinions now, the printed Bible, especially after having been translated into German by Martin Luther, and increasing literacy added to the subversion of clerical authorities. The interest in books increased with the rise of vernacular, non-Latin literary texts, beginning with Dante's Divine Comedy, the first literary text written in Italian.
Among others, the improvement of the distribution and the production of books and increased literacy made the development of print mass media possible.
Michael Giesecke (Sinnenwandel Sprachwandel Kulturwandel. Studien zur Vorgeschichte der Informationsgesellschaft, Frankfurt am Main: Suhrkamp, 1992) has shown that due to a division of labor among authors, printers and typesetters Gutenberg's invention increasingly led to a standardization of - written and unwritten - language in form of orthography, grammar and signs. To communicate one's ideas became linked to the use of a kind of code, and reading became a kind of rite of passage, in every human's life an important step towards independency.
With the increasing linkage of knowledge to wide reading and learnedness, the history of knowledge becomes the history of readings, of readings dependent on chance and on circumstance.
For further details see:
Martin Warnke, Text und Technik,
Bruce Jones, Manuscripts, Books, and Maps: The Printing Press and a Changing World,
IDEA is another symmetric-key system. It is a block cipher, operating on 64-bit plaintext blocks, having a key-length of 128 bits.