PasswordUtility

The Passowrd Utility is the library behind the http://passwordutility.net public api service that allows anyone to either validate or generate new random passwords. The library is fairly simple in that it only has 2 important classes that you should care about:

• PwGenerator
• QualityEstimation

Password Generation

The first one, as the name implies, allows you to generate a new random password. By default, the PwGenerator.Generate() method creates passwords of a given length, as defined by the user, containing only lower case alphabetic characters. The method offers additional parameters to allow users to generate more complicated passwords that contain numbers, upper case characters and special characaters. The signature of the method is:

public static ProtectedString Generate(
  int passwordLength, 
  bool useUpperCase = false, 
  bool useDigits = false, 
  bool useSpecialCharacters = false)

By setting the appropriate parameters, you generate the password you need. For example, if you want a password 15 characters long with upper case and special characters then you would call the method like this:

var password  = PwGenerator.Generate(15, true, false, true).ReadString();

Notice how we use .ReadString(); in order to transform the ProtectedString to a standard string. You chose what ever meets your needs best.

Password Strength Validation

Another handy feature of this library is the ability to validate a password and check for strength and entropy. The algorithm behind the calculation is pretty complicated and I chose to re-use the excellent implementation from KeePass rather than to roll my own. To validate a password all you have to do is call the QualityEstimation class like the example below:

uint result = QualityEstimation.EstimatePasswordBits(<YourPasswordString>.ToCharArray());

The result of this operation is an unsigned integer between 0 and 100. The closer to 100 the stronger the password is. The method signature is: public static uint EstimatePasswordBits(char[] vPasswordChars);

I hope you find this little library handy and please raise an issue with any requests or bugs. `