Password length parameter

In telecommunication, a password length parameter is a basic parameter the value of which affects password strength against brute force attack and so is a contributor to computer security.

One use of the password length parameters is in the expression P = L × R / S , where P is the probability that a password can be guessed in its lifetime, L is the maximum lifetime a password can be used to log in to a system, R is the number of guesses per unit of time, and S is the number of unique algorithm-generated passwords (the 'password space').

The degree of password security is determined by the probability that a password can be guessed in its lifetime.