The 19th Century: Machine-Assisted Manufacturing Eli Whitney's proposal for a simplification and standardization of component parts marked a further milestone in the advance of the automation of work processes. In 1797 he suggested the manufacture of muskets with completely interchangeable parts. As opposed to the older method under which each gun was the individual product of a highly skilled gunsmith and each part hand-fitted, his method permitted large production runs of parts that were readily fitted to other parts without adjustment and could relatively easy be performed by machines. By the middle of the 19th century the general concepts of division of labor, assembly of standardized parts and machine-assisted manufacture were well established. On both sides of the Atlantic large factories were in operation, which used specialized machines to improve costs, quality and quantity of their products.

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Asymmetric or Public-Key-Cryptosystems 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: http://world.std.com/~franl/crypto/rsa-guts.html. · 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: http://www.rsa.com/rsalabs/faq/ http://www.rsa.com/rsalabs/faq/questions.html or: http://www.pgpi.org 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: http://news.voila.fr/news/fr.misc.cryptologie 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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Friedrich Kittler, The History of Communication Media In this essay, Friedrich Kittler, one of the world's leading media theorists and media historicist, offers a concise and fascinating history of communication technologies in general terms from its beginnings up to now, provoking new insights by showing interesting interdependencies. http://www.ctheory.com/ga1.14.html

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