Key clustering: Difference between revisions

Revision as of 17:20, 13 April 2007

Revision as of 21:42, 13 December 2007

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==Importance==

If an 'attacker' tries to break a cipher by [[brute-force]] (trying all possible keys until it finds the correct key) then key clustering will result in an easier attack on a particular cipher text. If there are N possible keys with out any key clustering then the attacker will on average need to try N/2 keys to decrypt it and a worst case of trying all N keys. If there are two keys that are clustered then the average number of keys to try is reduced to N/4 (worst case is N-1 keys). If three keys cluster than average attempt is only N/6 attempts.

==External links==