Brute-force search is a general problem-solving strategy and algorithmic paradigm in computer science. In addition, it entails methodically listing all potential candidates for the solution and determining whether each one satisfies the problem's statement.

A brute-force algorithm that determines a natural number's divisors would list all integers from 1 to n and determine whether each one divides n exactly. For the eight queens puzzle, a brute-force method would look at every possible arrangement of 8 pieces on the 64-square chessboard and determine whether each (queen) piece could attack any other part in that arrangement.

A brute-force search is easy to set up and will always find a solution if one exists. However, the costs of setting up a brute-force search are proportional to the number of possible solutions, which tends to proliferate as the size of a practical problem increases (called a "combinatorial explosion"). So, brute-force search is usually used when the problem is small or when there are problem-specific heuristics that we can use to narrow down the list of possible solutions to something we can handle. The method is also used when speed is less important than how easy it is to use.

Alternatives

Many other search methods, called metaheuristics, are made to take advantage of different kinds of incomplete information about the solution. We can also use heuristics to cut off parts of the search process early. For example, the minimax principle shows it for searching game trees, eliminating many subtrees early in the search. In some fields, like language parsing, techniques like chart parsing can take advantage of constraints to turn a problem with exponential complexity into one with polynomial complexity. Finally, constraint propagation, accessible in Constraint programming languages, can be used in many situations, like Constraint Satisfaction Problems, to narrow the search space significantly. 

In addition, you can also reduce the number of problems to look for by changing the whole situation to a simpler one. For example, in computer chess, instead of computing the full minimax tree of all possible moves for the rest of the game, a smaller tree of minimax possibilities is calculated by cutting the tree after a certain number of activities and using a static evaluation function to estimate the rest of the tree.

Cryptography

A brute-force attack in cryptography involves repeatedly testing all potential keys until the correct key is discovered. Theoretically, an attacker who cannot exploit any flaws in an encryption system that would otherwise make their task simpler can use this strategy against any encrypted data (aside from a one-time pad) without being detected.

The practical viability of a brute force attack depends on the length of the encryption key, with longer keys being exponentially more challenging to crack than shorter ones. Obfuscating the data to be encoded can reduce the effectiveness of brute force attacks and make it more difficult for an attacker to determine when he has cracked the code. One way to gauge its strength is how long it would theoretically take an attacker to launch a successful brute-force attack against an encryption system.

Conclusion

The brute-force algorithm is a method that always finds a solution to a problem, even if it's in a different area. It helps solve simple problems and gives a solution we can use to compare other design methods, but it's slow and inefficient.