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Showing posts with label Encryption. Show all posts
Showing posts with label Encryption. Show all posts

Saturday, July 12, 2014

What is Symmetric Key Encryption

Symmetric Key Encryption is one of Cryptographic Tools use for secret communication , some times called conventional encryption or single-key encryption .

This diagram explain algorithm :

We have in diagram 5 things , plaintext , encryption algorithm , secret key , decryption algorithm , and ciphertext .

How algorithm run ?
Plaintext : Our message we need to transfer to another side , it's our in put that fed into encryption algorithm .
Encryption Algorithm :It's do some substitutions and transformations on the plaintext , to encrypting plaintext by using secret key information .
Secret key :It's have information that need to encryption and decryption .
Decryption Algorithm : We can say reverse of encryption , take ciphertext and by using secret key to decryption message to original plaintext .
Ciphertext : scrambled message encrypted by encryption algorithm using secret key information and transfer to other side , it will be input to decryption algorithm , and by using secret key will be original plaintext .

To make this symmetric strong we need tow things :
first : strong algorithm , to encrypting message .
second : secret key must keep secure .

Tow way to Attacking Symmetric Encryption :
1- cryptanalysis , to use it we need some knowledge of the general characteristics of the plaintext .
2- brute-force attack , we try all possible keys until plaintext is obtained .

Sources: Computer Security: Principles and Practice by William Stallings and Lawrie Brown .
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