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 By the middle of the 19th century the general concepts of |
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Key-Systems 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: |
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Actual Findings on Internet Advertising Although Web advertising becomes a significant portion of marketing budgets, advertisers are still unsure on how to unlock the potential of the Internet. Current findings show that: - Consumer brands spend only a fraction of their advertising budget on on-line advertising. - Technology companies spend five times more on advertising in the WWW. - While banner campaigns are still popular, there is no standardized solution for on-line advertising. - Ad pricing is based on CPM (costs per 1.000 visitors), rather than on results. - Personalized targeting has not yet taken hold. Instead advertisers mainly target on content. At the moment three dominant models are used for Internet advertising: Destination Sites: They use entertainment, high production values and information to pull users in and bring them back again. Micro Sites: Content sites or networks host small clusters of brand pages. Banner Campaigns: Those include other forms of Web advertising like sponsorships. |
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water-clocks The water-clocks are an early long-distance-communication-system. Every communicating party had exactly the same jar, with a same-size-hole that was closed and the same amount of water in it. In the jar was a stick with different messages written on. When one party wanted to tell something to the other it made a fire-sign. When the other answered, both of them opened the hole at the same time. And with the help of another fire-sign closed it again at the same time, too. In the end the water covered the stick until the point of the wanted message. |
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Hieroglyphs Hieroglyphs are pictures, used for writing in ancient Egypt. First of all those pictures were used for the names of kings, later more and more signs were added, until a number of 750 pictures |
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Aeneas Tacticus Supposedly his real name was Aeneas of Stymphalus. He was a Greek military scientist and cryptographer. He invented an optical system for communication similar to a telegraph: the |
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