public static string GeneratePassword()
{
const int MAXIMUM_PASSWORD_ATTEMPTS = 10000;
bool includeLowercase = true;
bool includeUppercase = true;
bool includeNumeric = true;
bool includeSpecial = true;
int lengthOfPassword = 8;
PasswordGeneratorSettings settings = new PasswordGeneratorSettings(includeLowercase, includeUppercase, includeNumeric, includeSpecial, lengthOfPassword);
string password;
if (!settings.IsValidLength())
{
password = settings.LengthErrorMessage();
}
else
{
int passwordAttempts = 0;
do
{
password = PasswordGenerator.GeneratePassword(settings);
passwordAttempts++;
}while (passwordAttempts < MAXIMUM_PASSWORD_ATTEMPTS && !PasswordGenerator.PasswordIsValid(settings, password));
password = PasswordGenerator.PasswordIsValid(settings, password) ? password : "******";
}
return(password);
}
/// <summary>
/// Generates a random password based on the rules passed in the settings parameter
/// </summary>
/// <param name="settings">Password generator settings object</param>
/// <returns>Password or try again</returns>
public static string GeneratePassword(PasswordGeneratorSettings settings)
{
const int MAXIMUM_IDENTICAL_CONSECUTIVE_CHARS = 2;
char[] password = new char[settings.PasswordLength];
int characterSetLength = settings.CharacterSet.Length;
System.Random random = new System.Random();
for (int characterPosition = 0; characterPosition < settings.PasswordLength; characterPosition++)
{
password[characterPosition] = settings.CharacterSet[random.Next(characterSetLength - 1)];
bool moreThanTwoIdenticalInARow =
characterPosition > MAXIMUM_IDENTICAL_CONSECUTIVE_CHARS &&
password[characterPosition] == password[characterPosition - 1] &&
password[characterPosition - 1] == password[characterPosition - 2];
if (moreThanTwoIdenticalInARow)
{
characterPosition--;
}
}
return(string.Join(null, password));
}
/// <summary>
/// When you give it a password and some settings, it validates the password against the settings.
/// </summary>
/// <param name="settings">Password settings</param>
/// <param name="password">Password to test</param>
/// <returns>True or False to say if the password is valid or not</returns>
public static bool PasswordIsValid(PasswordGeneratorSettings settings, string password)
{
const string REGEX_LOWERCASE = @"[a-z]";
const string REGEX_UPPERCASE = @"[A-Z]";
const string REGEX_NUMERIC = @"[\d]";
const string REGEX_SPECIAL = @"([!#$%&*@\\])+";
bool lowerCaseIsValid = !settings.IncludeLowercase || (settings.IncludeLowercase && Regex.IsMatch(password, REGEX_LOWERCASE));
bool upperCaseIsValid = !settings.IncludeUppercase || (settings.IncludeUppercase && Regex.IsMatch(password, REGEX_UPPERCASE));
bool numericIsValid = !settings.IncludeNumbers || (settings.IncludeNumbers && Regex.IsMatch(password, REGEX_NUMERIC));
bool symbolsAreValid = !settings.IncludeSpecial || (settings.IncludeSpecial && Regex.IsMatch(password, REGEX_SPECIAL));
return(lowerCaseIsValid && upperCaseIsValid && numericIsValid && symbolsAreValid);
}