What is A Brute force attack

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In cryptography, a brute-force attack, or exhaustive key search, is really a cryptanalytic attack that may, in theory, be used against any encrypted information (except for information encrypted in an information-theoretically secure manner). Such an attack may be used when it is not possible to take advantage of other weaknesses in an encryption method (if any exist) that would make the task simpler. It consists of systematically checking all feasible keys or passwords till the right one is discovered. In the worst case, this would involve traversing the entire search space.

When password guessing, this method is very quick when used to check all brief passwords, but for longer passwords other techniques like the dictionary attack are used because of the time a brute-force search requires.

When key guessing, the key length used in the cipher determines the practical feasibility of performing a brute-force attack, with longer keys exponentially more difficult to crack than shorter ones. A cipher having a key length of N bits may be broken inside a worst-case time proportional to 2N and an typical time of half that.

Brute-force attacks can be made less efficient by obfuscating the data to be encoded, something that tends to make it more difficult for an attacker to recognize when he/she 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.

Brute-force attacks are an application of brute-force search, the common problem-solving method of enumerating all candidates and checking each one.

The term "brute-force" isn't the only term to name such a kind of attack. It can also be known as "bruteforce", "brute force" and just "brute" (that is typical in names of programs that carry out brute-force attacks).

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