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1,155 bytes removed ,  21:12, April 1, 2009
undo edit by User:Markr. That "example" confuses me
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'''Public-key encryption''' is a kind of [[encryption]] in which both the message and the public key are public. There is a private key used known only to the individual. This differs from the traditional (so-called "private-key") encryption, in which the key is kept secret from the intended recipient. Public-key encryption is a form of ''[[symmetry|asymmetric]] encryption'', meaning that it is much easier to encrypt a message than to decrypt it, at least without knowing the encryption key; this is the reason that the key has to be made public.
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'''Public-key encryption''' is a kind of [[encryption]] in which both the message and the key are public. This differs from the traditional (so-called "private-key") encryption, in which the key is kept secret from the intended recipient. Public-key encryption is a form of ''[[symmetry|asymmetric]] encryption'', meaning that it is much easier to encrypt a message than to decrypt it, at least without knowing the encryption key; this is the reason that the key has to be made public.
    
Well-known public-key encryption algorithms include '''Diffie-Hellman''',
 
Well-known public-key encryption algorithms include '''Diffie-Hellman''',
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The RSA algorithm was put to the test in 1991, when RSA Laboratories released the "RSA Factoring Challenge". The challenge consisted of a list of progressively larger numbers, which, when fully decrypted, read "The magic words are [[squeamish ossifrage]]."<ref>[http://citeseer.ist.psu.edu/1393.html "The Magic Words Are Squeamish Ossifrage"], by Atkins, Graff, Lenstra, and Leyl</ref> Although the challenge was withdrawn in 2007, the RSA algorithm is still widely considered acceptable for business purposes.
 
The RSA algorithm was put to the test in 1991, when RSA Laboratories released the "RSA Factoring Challenge". The challenge consisted of a list of progressively larger numbers, which, when fully decrypted, read "The magic words are [[squeamish ossifrage]]."<ref>[http://citeseer.ist.psu.edu/1393.html "The Magic Words Are Squeamish Ossifrage"], by Atkins, Graff, Lenstra, and Leyl</ref> Although the challenge was withdrawn in 2007, the RSA algorithm is still widely considered acceptable for business purposes.
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==Example==
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Fred needs to send documents to many people. They dont need to be secure , but its important that they know for certain that the messge actually came from Fred.
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* Fred '''encrypts''' the message using his ''private key''. (only fred knows this key)
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* Fred sends the message
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* George gets the message (so do many other people , its not important)
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* George '''decrypts''' the message using Freds ''Public key''.
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* Only a message coded with the private key can be decoded wth the public key so George knows it came from Fred.
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* George drafts a reply and '''encrypts''' it with Freds ''Public key''.
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* only Freds ''private key'' can '''decrypt''' the message , so it is secure
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* Fred receives the message and decrypts it
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* its a valid message but Fred cant know who sent it , anyone with the public key could send to him.
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This form of public key encryption works best with sets of private and public keys. 
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==References==
 
==References==
 
<references/>
 
<references/>
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* [http://www.networkworld.com/news/64452_05-17-1999.html | Public key encryption for Dummies]
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* http://www2.krellinst.org/UCES/archive/modules/charlie/pke/
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[[Category:Cryptography]]
 
[[Category:Cryptography]]
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