Passwortstärke validieren

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/// <summary>
/// Validates the password.
/// </summary>
/// <param name="passwordToValidate">The password to validate.</param>
/// <param name="minimumPasswordLength">Minimum length of the password.</param> 
/// <param name="minimumNumberOfSpecialCharaters">The minimum number of special charaters.</param> 
/// <param name="minimumNumberOfUpperCaseCharaters">The minimum number of upper case charaters.</param> 
/// <param name="minimumNumberOfLowerCaseCharaters">The minimum number of lower case charaters.</param> 
/// <param name="minimumNumberOfNumericCharaters">The minimum number of numeric charaters.</param> 
/// <returns></returns> 
public bool ValidatePassword(string passwordToValidate, int minimumPasswordLength, int minimumNumberOfSpecialCharaters, int minimumNumberOfUpperCaseCharaters, int minimumNumberOfLowerCaseCharaters, int minimumNumberOfNumericCharaters)
{
    if (passwordToValidate == null || passwordToValidate.Length < minimumPasswordLength)
        return false;

    int numberOfSpecialCharaters = 0;
    int numberOfLowerCaseCharaters = 0;
    int numberOfUpperCaseCharaters = 0;
    int numberOfNumericCharaters = 0;

    var regexSpecialCharater = new Regex("[^A-Za-z0-9]");
    var regexLowerCaseCharater = new Regex("[a-z]");
    var regexUpperCaseCharater = new Regex("[A-Z]");
    var regexNumericCharaters = new Regex("[0-9]");

    for (int i = 0; i < passwordToValidate.Length; i++)
    {
        if (regexSpecialCharater.IsMatch(passwordToValidate[i].ToString()))
            numberOfSpecialCharaters++;

        if (regexLowerCaseCharater.IsMatch(passwordToValidate[i].ToString()))
            numberOfLowerCaseCharaters++;

        if (regexUpperCaseCharater.IsMatch(passwordToValidate[i].ToString()))
            numberOfUpperCaseCharaters++;

        if (regexNumericCharaters.IsMatch(passwordToValidate[i].ToString()))
            numberOfNumericCharaters++;
    }

    return (numberOfSpecialCharaters >= minimumNumberOfSpecialCharaters)
           && (numberOfLowerCaseCharaters >= minimumNumberOfLowerCaseCharaters)
           && (numberOfUpperCaseCharaters >= minimumNumberOfUpperCaseCharaters)
           && (numberOfNumericCharaters >= minimumNumberOfNumericCharaters);
}