brute force attack
A method of breaking a cipher (that is, to decrypt a specific encrypted text) by trying every possible key. The quicker the brute force attack, the weaker the cipher. Feasibility of brute force attack depends on the key length of the cipher, and on the amount of computational power available to the attacker. Brute force attack is impossible against the ciphers with variable-size key, such as a one-time pad cipher.