Editing Brute-force search (section)

==In cryptography==
{{main|Brute-force attack}}

In [[cryptography]], a ''brute-force attack'' involves systematically checking all possible [[key (cryptography)|keys]] until the correct key is found.<ref>Mark Burnett, [http://www.cs.virginia.edu/~csadmin/gen_support/brute_force.php "Blocking Brute Force Attacks"] {{Webarchive|url=https://web.archive.org/web/20161203020306/http://www.cs.virginia.edu/~csadmin/gen_support/brute_force.php |date=2016-12-03 }}, ''UVA Computer Science'', 2007</ref> This [[strategy]] can in theory be used against any encrypted data<ref>{{cite book|url=http://www.crypto-textbook.com|page=7|title=Understanding Cryptography: A Textbook for Students and Practitioners|author1=Christof Paar |author2=Jan Pelzl |author3=Bart Preneel |publisher=Springer|year=2010|isbn=978-3-642-04100-6}}</ref> (except a [[one-time pad]]) by an attacker who is unable to take advantage of any weakness in an encryption system that would otherwise make his or her task easier.

The [[key length]] used in the encryption determines the practical feasibility of performing a brute force attack, with longer keys exponentially more difficult to crack than shorter ones. Brute force attacks can be made less effective by [[obfuscation|obfuscating]] the data to be encoded, something that makes it more difficult for an attacker to recognise when he has cracked the code. One of the measures of the strength of an encryption system is how long it would theoretically take an attacker to mount a successful brute force attack against it.