The Brute Force method and/or method of the raw force is the technical term for a solution method of heavy problems from the range of the computer science and the game theory, which are based on trying all (or at least a substantial part of the which are applicable) variants out.

Computer science

For many problems there are no efficient algorithms in computer science. The most natural and simplest beginning for the algorithmic solution of a problem consists then of trying simply all potenziellen solutions one after the other. One calls this method "„Brute Force "“.

Admits is this method particularly in the range of computer security. Classical example of use for Brute Force attacks is cracking passwords. Often the passwords are coded in such a list by a Hash function. A computation of the password from the Hash value is practically not possible. A Cracker can compute however the Hash values of many passwords. If a value agrees with a value on the list of the coded passwords, it found the suitable password. Brute Force means here then the simple trying of all password possibilities out. Even with longer passwords the Cracker can come to success, if it tries more frequently used passwords out, e.g. from a "“dictionary"”. In this case one speaks also of a dictionary attack (English "„Dictionary Attack "“).

A Cracker can procure itself the software for such an attack via Internet, in order to e.g. attack services like the ftp.

Because of the versatile applicability and the immense arithmetic performance of today's computers, ever longer passwords are necessary for a sufficient protection.

Game theory

In the game theory one names a strategy the Brute Force method, in which the variant tree up to a certain depth is completely analyzed. A weighing function for everyone of the positions arising with it serves thereby for decision making for the best course.

The expenditure for the Brute Force method grows exponentially with the used maximum depth; thus the hardware of this method sets a natural border.

The Brute Force method can be refined with the most diverse methods, what can lead by exponential growth mentioned to substantial improvements. A very usual improvement is the alpha beta search: if a course is disproved in a certain depth by a certain countermove, then it is useless to look for still better refutations.

Another usual method is to regard starting from a certain depth only "„forcing "“courses. In chess would be this for instance chess requirements or impact courses.

Cryptanalysis

With an Brute Force attack in the cryptanalysis all possible keys are successively tried one after the other (Exhaustion). Therefore one speaks also of complete key search. The sequence is selected after the probability, this is if necessary however helpful with usually (pseudo) coincidentally generated keys a little. The key length plays likewise a role, since on average half of the key area must be tried at least, before the key is found. This method is meaningful also with modern coding procedures, if from the use of a relatively weak password can be proceeded. One speaks then of a dictionary attack, since certain word lists (the dictionaries) are used.

An attack on the coding procedure is in practice offering no prospects with modern algorithms using an accordingly complex key. It would last even using several millions high speed computers thousands of years, in order to try one after the other only a considerable fraction of the possible key area.

Therefore an Brute Force attack in practice always applies for the concrete password. This however is also in practice very frequently successful, since most users use short passwords. Already on a commercial computer several hundred out hundred-out-ending passwords per second can be tried out. With a dictionary attack all conceivable words of dutzender languages can be examined within fewer seconds. An individual word is very uncertain therefore.

Related links

• Connection of Brute Force attacks and password lengths
• Brute Force method in turbo Pascal

Articles in category "Brute Force method"

We found here 4 articles.

Related Websites

We found here 3 related websites.

• brute force - Webopedia.com
  In addition, sometimes a particular problem can be solved so quickly with a brute force method that it doesn't make sense to waste time devising a more ...


• Brute force attack - Wikipedia, the free encyclopedia
  In general, a symmetric key cipher is considered secure if there is no method less expensive (in time, memory requirements, etc) than brute force; ...


• Brute-force search - Wikipedia, the free encyclopedia
  Brute-force search is also useful as "baseline" method when benchmarking other algorithms or ... The main disadvantage of the brute-force method is that, ...