Symmetric cipher: Difference between revisions

Latest revision as of 04:38, 2 November 2008

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-A '''symmetric cipher''' is a [[cipher]] in which the sender and receiver of a message must have the same [[cryptographic key]]. This contrasts with an [[asymmetric cipher]] or [[public key]] technique in which two keys are used.
+#REDIRECT [[Symmetric key cryptography]]
-There are two main types of symmetric cipher, [[stream cipher]]s and [[block cipher]]s.
-In general, symmetric ciphers are much faster than asymmetric ones, but [[key management]] for symmetric ciphers can be difficult. For <math>n</math> people to communicate, <math>n(n-1)/2</math> keys are needed and all of them must be ''securely'' communicated before they can be used. This problem is often managed by using a [[hybrid cryptosystem]] in which public key techniques handle key management and symmetric ciphers do the encryption of actual messages.