如何检查密码强度？

Question

如何使用.Net Framework检查密码的强度（作为string）？

Answer 1

基本但合乎逻辑：

enum PasswordScore
{
    Blank = 0,
    VeryWeak = 1,
    Weak = 2,
    Medium = 3,
    Strong = 4,
    VeryStrong = 5
}

public class PasswordAdvisor
{
    public static PasswordScore CheckStrength(string password)
    {
        int score = 1;

        if (password.Length < 1)
            return PasswordScore.Blank;
        if (password.Length < 4)
            return PasswordScore.VeryWeak;

        if (password.Length >= 8)
            score++;
        if (password.Length >= 12)
            score++;
        if (Regex.Match(password, @"/\d+/", RegexOptions.ECMAScript))
            score++;
        if (Regex.Match(password, @"/[a-z]/", RegexOptions.ECMAScript) &&
            Regex.Match(password, @"/[A-Z]/", RegexOptions.ECMAScript))
            score++;
        if (Regex.Match(password, @"/.[!,@,#,$,%,^,&,*,?,_,~,-,£,(,)]/",  RegexOptions.ECMAScript))
            score++;

        return (PasswordScore)score;
    }
}

参考：http://passwordadvisor.com/CodeAspNet.aspx

Answer 2

这是我写的一个简单的：

/// <summary>
/// Evaluates a password
/// </summary>
public class PasswordEvaluator
{
    public string Password { get; private set; }
    public int Length { get; private set; }
    public int TotalNumberChars { get; private set; }
    public bool ContainsNumberChars{get { return TotalNumberChars > 0; }}
    public int TotalUppercaseChars { get; private set; }
    public bool ContainsUppercaseChars { get { return TotalUppercaseChars > 0; } }
    public int TotalLowercaseChars { get; private set; }
    public bool ContainsLowercaseChars { get { return TotalLowercaseChars > 0; } }
    public int TotalSpecialChars { get; private set; }
    public bool ContainsSpecialChars { get { return TotalSpecialChars > 0; } }

    public PasswordEvaluator(string password)
    {
        Password = password.Trim();
        Length = Password.Length;
        foreach (var c in Password)
        {
            var charCode = (int)c;
            if (charCode >= 48 && charCode <= 57) TotalNumberChars++;
            else if (charCode >= 65 && charCode <= 90) TotalUppercaseChars++;
            else if (charCode >= 97 && charCode <= 122) TotalLowercaseChars++;
            else TotalSpecialChars++;
        }
    }
    public bool StrongEnough()
    {
        // Minimum length requirement
        if (Length < Settings.PasswordMinLength) return false;

        // Mixed case requirement
        if (!ContainsLowercaseChars && !ContainsUppercaseChars) return false;

        // Special chars requirement
        if (TotalSpecialChars < 3) return false;

        // Min lower case chars requirement
        if (TotalLowercaseChars < 3) return false;

        // Min upper case chars requirement
        if (TotalUppercaseChars < 3) return false;

        return true;
    }
}

您可以在StrongEnough()

中定义自己的规则

Answer 3

“密码强度”是一个相当通用的术语，它可能意味着密码字符数，使用的字符范围（基数），破解（暴力）密码所需的时间等。

衡量密码加密强度的最佳方法之一是计算密码entropy的位数（尽管这通常对于测量随机密码更准确。否则你会得到 over 估计的熵结果，

// Only accurate for passwords in ASCII.
public double CalculateEntropy(string password)
{
    var cardinality = 0;

    // Password contains lowercase letters.
    if (password.Any(c => char.IsLower(c)))
    {
        cardinality = 26;
    }

    // Password contains uppercase letters.
    if (password.Any(c => char.IsUpper(c)))
    {
        cardinality += 26;
    }

    // Password contains numbers.
    if (password.Any(c => char.IsDigit(c)))
    {
        cardinality += 10;
    }

    // Password contains symbols.
    if (password.IndexOfAny("\\|¬¦`!\"£$%^&*()_+-=[]{};:'@#~<>,./? ".ToCharArray()) >= 0)
    {
        cardinality += 36;
    }

    return Math.Log(cardinality, 2) * password.Length;
}

Answer 4

如果我可以展示我的定制实例，例如Teoman Soygul（以及我见过的其他类似的人）......我的实现有不同的评分方案，并使用最低要求以及检查重复字符。

public enum PasswordScore
{
    Blank = 0,
    TooShort = 1,
    RequirementsNotMet = 2,
    VeryWeak = 3,
    Weak = 4,
    Fair = 5,
    Medium = 6,
    Strong = 7,
    VeryStrong = 8
}

public static PasswordScore CheckStrength(string password)
    {
        int score = 0;

        // using three requirements here:  min length and two types of characters (numbers and letters)
        bool blnMinLengthRequirementMet = false;
        bool blnRequirement1Met = false;
        bool blnRequirement2Met = false;

        // check for chars in password
        if (password.Length < 1)
            return PasswordScore.Blank;

        // if less than 6 chars, return as too short, else, plus one
        if (password.Length < 6)
        {
            return PasswordScore.TooShort;
        }
        else
        {
            score++;
            blnMinLengthRequirementMet = true;
        }

        // if 8 or more chars, plus one
        if (password.Length >= 8)
            score++;

        // if 10 or more chars, plus one
        if (password.Length >= 10)
            score++;

        // if password has a number, plus one
        if (Regex.IsMatch(password, @"[\d]", RegexOptions.ECMAScript))
        {
            score++;
            blnRequirement1Met = true;
        }

        // if password has lower case letter, plus one
        if (Regex.IsMatch(password, @"[a-z]", RegexOptions.ECMAScript))
        {
            score++;
            blnRequirement2Met = true;
        }

        // if password has upper case letter, plus one
        if (Regex.IsMatch(password, @"[A-Z]", RegexOptions.ECMAScript))
        {
            score++;
            blnRequirement2Met = true;
        }

        // if password has a special character, plus one
        if (Regex.IsMatch(password, @"[~`!@#$%\^\&\*\(\)\-_\+=\[\{\]\}\|\\;:'\""<\,>\.\?\/£]", RegexOptions.ECMAScript))
            score++;

        // if password is longer than 2 characters and has 3 repeating characters, minus one (to minimum of score of 3)
        List<char> lstPass = password.ToList();
        if (lstPass.Count >= 3)
        {
            for (int i = 2; i < lstPass.Count; i++)
            {
                char charCurrent = lstPass[i];
                if (charCurrent == lstPass[i - 1] && charCurrent == lstPass[i - 2] && score >= 4)
                {
                    score++;
                }
            }
        }

        if (!blnMinLengthRequirementMet || !blnRequirement1Met || !blnRequirement2Met)
        {
            return PasswordScore.RequirementsNotMet;
        }

        return (PasswordScore)score;
    }

Answer 5

这是我使用的一个简单的JavaScript示例，将其移植到.Net应该不是很难，

    var getStrength = function (passwd) {
    intScore = 0;
    intScore = (intScore + passwd.length);
    if (passwd.match(/[a-z]/)) {
        intScore = (intScore + 1);
    }
    if (passwd.match(/[A-Z]/)) {
        intScore = (intScore + 5);
    }
    if (passwd.match(/\d+/)) {
        intScore = (intScore + 5);
    }
    if (passwd.match(/(\d.*\d)/)) {
        intScore = (intScore + 5);
    }
    if (passwd.match(/[!,@#$%^&*?_~]/)) {
        intScore = (intScore + 5);
    }
    if (passwd.match(/([!,@#$%^&*?_~].*[!,@#$%^&*?_~])/)) {
        intScore = (intScore + 5);
    }
    if (passwd.match(/[a-z]/) && passwd.match(/[A-Z]/)) {
        intScore = (intScore + 2);
    }
    if (passwd.match(/\d/) && passwd.match(/\D/)) {
        intScore = (intScore + 2);
    }
    if (passwd.match(/[a-z]/) && passwd.match(/[A-Z]/) && passwd.match(/\d/) && passwd.match(/[!,@#$%^&*?_~]/)) {
        intScore = (intScore + 2);
    }
    return intScore;
}

Answer 6

这是我自己的代码，用于基于信息熵和NIST指南的密码强度检查器。然而，这种方法并未考虑“人类”语言因素。

public enum PasswordScore
{
    Blank,
    VeryWeak,
    Weak,
    Medium,
    Strong,
    VeryStrong
}

public static PasswordScore CheckPasswordStrength(string password)
{
    int N = 0;
    int L = password.Length;
    if (L == 0)
        return PasswordScore.Blank;
    if (Regex.IsMatch(password, @"[\d]", RegexOptions.ECMAScript))
        N += 10;
    if (Regex.IsMatch(password, @"[a-z]", RegexOptions.ECMAScript))
        N += 26;
    if (Regex.IsMatch(password, @"[A-Z]", RegexOptions.ECMAScript))
        N += 26;
    if (Regex.IsMatch(password, @"[~`!@#$%\^\&\*\(\)\-_\+=\[\{\]\}\|\\;:'\""<\,>\.\?\/£]", RegexOptions.ECMAScript) && password.Length > 8)
        N += 33;
    int H = Convert.ToInt32(L * (Math.Round(Math.Log(N) / Math.Log(2))));
    if (H <= 32) return PasswordScore.VeryWeak;
    if (H <= 48) return PasswordScore.Weak;
    if (H <= 64) return PasswordScore.Medium;
    if (H <= 80) return PasswordScore.Strong;
    return PasswordScore.VeryStrong;
}

Answer 7

应该代表几个参数检查密码的强度，例如是否存在特殊字符和数字，密码长度等。

我在下面的教程中找到了很好的演示：

http://tinytute.com/2014/06/03/animated-password-strength-checker-quick-easy/

jQuery代码块：

$(document).ready(function(){

    $("#textBox").keyup(function(){

        var passWord = $("#textBox").val();
        var passLength = passWord.length;
        var specialFlag = 0;
        var numberFlag = 0;
        var numberGenerator = 0;
        var total = 0;

        if(/^[a-zA-Z0-9- ]*$/.test(passWord) == false) {

            specialFlag =20;
        }


        if(passWord.match(/[0-9]/)) {

            numberFlag = 25;
        }

        if(passLength>4&&passLength<=6){
            numberGenerator =25;
        }else if(passLength>=7&&passLength<=9){
            numberGenerator =35;
        }else if(passLength>9){
            numberGenerator =55;
        }else if(passLength>0&&passLength<=4){
            numberGenerator =15;
        }else{
            numberGenerator =0;
        }

        total = numberGenerator + specialFlag + numberFlag;
        if(total<30){
            $('#progressBar').css('background-color','#CCC');
        }else if(total<60&&total>=30){

            $('#progressBar').css('background-color','#FF6600');

        }else if(total>=60&&total<90){

            $('#progressBar').css('background-color','#FFCC00');

        }else if(total>=90){

            $('#progressBar').css('background-color','#0f0');

        }
        $('#progressBar').css('width',total+'%');

    });

});