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Cryptography |
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Meaning: the latin "crypticus" resp. greek "krypikos" means hidden or concealed, "logos" means word and "graphos" means write.
With the development of written records in former civilzations it was recognized that secret transmission of messages is necessary. Soon there were techniques developed which are used till past century, which are substitution and permutation.
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The Skytale, which was used in ancient Greece, is based on a transposition algorithm
. The message was written on parchment, which is wrapped spirally around a rod. Only a person with a rod of the same radius could read the message again.
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Skytale |
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The algorithm which the roman emperor caesar used allegedly, and now called caesar cipher is a the typical monoalphabetic method
. Each character is shifted (substituted by) k steps in the alphabet. If someone is talking about Rot 13, this algorithm is meant with 13 steps. (Rotate 13)
At the time when Van Kerckhoffs and Shannons expressed their principles of characteristics of well designed algorithms, which are valid up to now, only this methods were known. In the 70s of the 20th century the principle of asymmetric encryption revolutionised cryptosgraphy.
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Linktipps |
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Cryptoshop Tipps |
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