How do I measure the strength of a password?

Question

I was looking for an effective algorithm that can give me an accurate idea of how strong a password is.

I found that several different websites use several different

Answer 1

I can't think of a specific algorithm to check the strengh of a password. What we do is we define several criterion and when the password respect a criteria, we add 1 to its score. When the password reach a threshold, the password is strong. Otherwise it is weak.

You can define many different level of strengh if with different throeshold, or you can define different value for a specific criteria. For example, if a password has 5 character, we add 1, but if it got 10, then we add 2.

here is a list of criterion to check for

Length (8 to 12 is ok, more is better) Contains lowercase letter Contains uppercase letter The upper case letter is NOT the first one. Contains number Contains symbols the last character is NOT a human like symbol (ex : . or !) Does not look like a dictionnary word. Some wise password crack contains library of word and letter substitutes (like Library --> L1br@ry )

Hope that help.