C# 生成随机密码

C# 生成随机密码,c#,passwords,random,C#,Passwords,Random,当我们网站上的用户丢失密码并进入丢失密码页面时,我们需要给他一个新的临时密码。我真的不在乎这是多么随机,或者如果它符合所有“需要的”强密码规则,我只想给他们一个密码,他们可以在以后更改 该应用程序是用C#编写的Web应用程序。因此,我想变得卑鄙,并寻求使用部分Guid的简单方法。i、 e Guid.NewGuid().ToString("d").Substring(1,8) 建议?想法?这个要大得多,但我认为它看起来更全面一些: ///////////////////////////////

当我们网站上的用户丢失密码并进入丢失密码页面时,我们需要给他一个新的临时密码。我真的不在乎这是多么随机,或者如果它符合所有“需要的”强密码规则,我只想给他们一个密码,他们可以在以后更改

该应用程序是用C#编写的Web应用程序。因此,我想变得卑鄙,并寻求使用部分Guid的简单方法。i、 e

Guid.NewGuid().ToString("d").Substring(1,8)

建议?想法?

这个要大得多,但我认为它看起来更全面一些:

///////////////////////////////////////////////////////////////////////////////
//示例:生成符合强密码的随机密码
//规则,不包含不明确的字符。
//
//要运行此示例,请使用控制台创建一个新的Visual C#项目
//应用程序模板,并将Class1.cs文件的内容替换为
//下面是代码。
//
//本规范和信息按“原样”提供,不提供任何形式的担保,
//明示或暗示,包括但不限于暗示
//适销性和/或适用于特定用途的保证。
// 
//版权所有(C)2004 Obviex(TM)。版权所有。
// 
使用制度;
使用System.Security.Cryptography;
/// 
///此类可以生成随机密码,其中不包括不明确的密码
///字符,如I、l和1。生成的密码将由
///7位ASCII符号。每四个字符将包含一个小写字母
///字符、一个大写字符、一个数字和一个特殊符号
///(例如“%”)的随机顺序。密码将始终以
///字母数字字符;它不会以一个特殊的符号开始(我们有
///这是因为一些后端系统不喜欢某些特殊的
///第一个位置中的字符)。
/// 
公共类随机密码
{
//定义默认的最小和最大密码长度。
私有静态int默认值\最小值\密码\长度=8;
私有静态int默认值\最大\密码\长度=10;
//定义分为组的受支持密码字符。
//您可以在这些组中添加(或删除)字符。
私有静态字符串密码\u CHARS\u LCASE=“abcdefgijkmnopqrstwxyz”;
私有静态字符串密码\u CHARS\u UCASE=“ABCDEFGHJKLMNPQRSTWXYZ”;
私有静态字符串密码\u CHARS\u NUMERIC=“23456789”;
私有静态字符串密码\u CHARS\u SPECIAL=“*$-+?\u&=!%{}/”;
/// 
///生成一个随机密码。
/// 
/// 
///随机生成的密码。
/// 
/// 
///生成的密码的长度将在
///随机。它将不小于最小默认值,并且
///不超过最大默认值。
/// 
公共静态字符串生成()
{
返回生成(默认\u最小\u密码\u长度,
默认值(最大密码长度);
}
/// 
///生成精确长度的随机密码。
/// 
/// 
///准确的密码长度。
/// 
/// 
///随机生成的密码。
/// 
公共静态字符串生成(整数长度)
{
返回生成(长度、长度);
}
/// 
///生成一个随机密码。
/// 
/// 
///最小密码长度。
/// 
/// 
///最大密码长度。
/// 
/// 
///随机生成的密码。
/// 
/// 
///生成的密码的长度将在
///随机的,它将随
///函数参数。
/// 
公共静态字符串生成(int minLength,
整数(最大长度)
{
//确保输入参数有效。
if(minLength
publicstringcreatepassword(int-length)
{
常量字符串valid=“abcdefghijklmnopqrstuvxyzabcdefghijklmnopqrstuvxyz1234567890”;
StringBuilder res=新的StringBuilder();
随机rnd=新随机();
而(0<长度--)
{
res.Append(有效[rnd.Next(有效.Length)]);
}
return res.ToString();
}

这有一个很好的好处,即可以从生成的密码的可用字符列表中进行选择(例如,仅限数字、仅限大写或仅限小写等)。

对于这种密码,我倾向于使用一种可能更容易生成“使用”的系统密码。很短,通常由可发音的片段和几个数字组成,并且没有字符间的歧义(是0还是O?是1还是I?)

string[] words = { 'bur', 'ler', 'meh', 'ree' };
string word = "";

Random rnd = new Random();
for (i = 0; i < 3; i++)
   word += words[rnd.Next(words.length)]

int numbCount = rnd.Next(4);
for (i = 0; i < numbCount; i++)
  word += (2 + rnd.Next(7)).ToString();

return word;
string[]words={'bur','ler','meh','ree'};
字串=”;
随机rnd=新随机();
对于(i=0;i<3;i++)
单词+=单词[rnd.Next(单词长度)]
int numbCount=rnd.Next(4);
对于(i=0;i

(直接在浏览器中键入,因此仅供参考。另外,添加更多单词).

我喜欢看生成密码,就像生成软件密钥一样。你应该从一组符合良好做法的字符中进行选择。使用什么并修改它以符合良好做法。不要将每个字母都放在字符数组中。有些字母在电话中更难说或理解


你也应该考虑在生成的密码上使用校验和,以确保它是由你生成的。一个很好的实现方法是使用.

始终存在。

< p>我不喜欢成员身份。GuangtApAsWord()创建的密码,因为它们太丑陋,并且有太多特殊字符。

此代码生成一个10位数的不太难看的密码

string password = Guid.NewGuid().ToString("N").ToLower()
                      .Replace("1", "").Replace("o", "").Replace("0","")
                      .Substring(0,10);

当然,我可以使用正则表达式来完成所有替换,但这在我看来更具可读性和可维护性。

我创建了类似于成员资格提供程序中可用的方法。如果您不想在某些应用程序中添加web引用,这是非常有用的string[] words = { 'bur', 'ler', 'meh', 'ree' }; string word = ""; Random rnd = new Random(); for (i = 0; i < 3; i++) word += words[rnd.Next(words.length)] int numbCount = rnd.Next(4); for (i = 0; i < numbCount; i++) word += (2 + rnd.Next(7)).ToString(); return word;
string password = Guid.NewGuid().ToString("N").ToLower()
                      .Replace("1", "").Replace("o", "").Replace("0","")
                      .Substring(0,10);
public static string GeneratePassword(int Length, int NonAlphaNumericChars)
    {
        string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
        string allowedNonAlphaNum = "!@#$%^&*()_-+=[{]};:<>|./?";
        Random rd = new Random();

        if (NonAlphaNumericChars > Length || Length <= 0 || NonAlphaNumericChars < 0)
            throw new ArgumentOutOfRangeException();

            char[] pass = new char[Length];
            int[] pos = new int[Length];
            int i = 0, j = 0, temp = 0;
            bool flag = false;

            //Random the position values of the pos array for the string Pass
            while (i < Length - 1)
            {
                j = 0;
                flag = false;
                temp = rd.Next(0, Length);
                for (j = 0; j < Length; j++)
                    if (temp == pos[j])
                    {
                        flag = true;
                        j = Length;
                    }

                if (!flag)
                {
                    pos[i] = temp;
                    i++;
                }
            }

            //Random the AlphaNumericChars
            for (i = 0; i < Length - NonAlphaNumericChars; i++)
                pass[i] = allowedChars[rd.Next(0, allowedChars.Length)];

            //Random the NonAlphaNumericChars
            for (i = Length - NonAlphaNumericChars; i < Length; i++)
                pass[i] = allowedNonAlphaNum[rd.Next(0, allowedNonAlphaNum.Length)];

            //Set the sorted array values by the pos array for the rigth posistion
            char[] sorted = new char[Length];
            for (i = 0; i < Length; i++)
                sorted[i] = pass[pos[i]];

            string Pass = new String(sorted);

            return Pass;
    }
^(?=\b\w*[a-z].*[a-z]\w*\b)(?=\b\w*[A-Z].*[A-Z]\w*\b)(?=\b\w*[0-9].*[0-9]\w*\b)[a-zA-Z0-9]{8,}$
public static string GeneratePassword(int lowercase, int uppercase, int numerics) {
    string lowers = "abcdefghijklmnopqrstuvwxyz";
    string uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string number = "0123456789";

    Random random = new Random();

    string generated = "!";
    for (int i = 1; i <= lowercase; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            lowers[random.Next(lowers.Length - 1)].ToString()
        );

    for (int i = 1; i <= uppercase; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            uppers[random.Next(uppers.Length - 1)].ToString()
        );

    for (int i = 1; i <= numerics; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            number[random.Next(number.Length - 1)].ToString()
        );

    return generated.Replace("!", string.Empty);

}
String randomPassword = GeneratePassword(3, 3, 3);
int count = 0;
 private void button1_Click(object sender, EventArgs e)
    {
    // This clears the textBox, resets the count, and starts the timer
        count = 0;
        textBox1.Clear();
        timer1.Start();
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
    // This generates the password, and types it in the textBox
        count += 1;
            string possible = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
            string psw = "";
            Random rnd = new Random { };
            psw += possible[rnd.Next(possible.Length)];
            textBox1.Text += psw;
            if (count == (comboBox1.SelectedIndex + 1))
            {
                timer1.Stop();
            }
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        // This adds password lengths to the comboBox to choose from.
        comboBox1.Items.Add("1");
        comboBox1.Items.Add("2");
        comboBox1.Items.Add("3");
        comboBox1.Items.Add("4");
        comboBox1.Items.Add("5");
        comboBox1.Items.Add("6");
        comboBox1.Items.Add("7");
        comboBox1.Items.Add("8");
        comboBox1.Items.Add("9");
        comboBox1.Items.Add("10");
        comboBox1.Items.Add("11");
        comboBox1.Items.Add("12");
    }
    private void button2_click(object sender, EventArgs e)
    {
        // This encrypts the password
        tochar = textBox1.Text;
        textBox1.Clear();
        char[] carray = tochar.ToCharArray();
        for (int i = 0; i < carray.Length; i++)
        {
            int num = Convert.ToInt32(carray[i]) + 10;
            string cvrt = Convert.ToChar(num).ToString();
            textBox1.Text += cvrt;
        }
    }
using System;
using System.Security.Cryptography;

public static string GetRandomAlphanumericString(int length)
{
    const string alphanumericCharacters =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
        "abcdefghijklmnopqrstuvwxyz" +
        "0123456789";
    return GetRandomString(length, alphanumericCharacters);
}

public static string GetRandomString(int length, IEnumerable<char> characterSet)
{
    if (length < 0)
        throw new ArgumentException("length must not be negative", "length");
    if (length > int.MaxValue / 8) // 250 million chars ought to be enough for anybody
        throw new ArgumentException("length is too big", "length");
    if (characterSet == null)
        throw new ArgumentNullException("characterSet");
    var characterArray = characterSet.Distinct().ToArray();
    if (characterArray.Length == 0)
        throw new ArgumentException("characterSet must not be empty", "characterSet");

    var bytes = new byte[length * 8];
    new RNGCryptoServiceProvider().GetBytes(bytes);
    var result = new char[length];
    for (int i = 0; i < length; i++)
    {
        ulong value = BitConverter.ToUInt64(bytes, i * 8);
        result[i] = characterArray[value % (uint)characterArray.Length];
    }
    return new string(result);
}
public static string GenerateRandomCode(int length)
{
    Random rdm = new Random();
    StringBuilder sb = new StringBuilder();

    for(int i = 0; i < length; i++)
        sb.Append(Convert.ToChar(rdm.Next(101,132)));

    return sb.ToString();
}
var generator = new PasswordGenerator(minimumLengthPassword: 8,
                                      maximumLengthPassword: 15,
                                      minimumUpperCaseChars: 2,
                                      minimumNumericChars: 3,
                                      minimumSpecialChars: 2);
string password = generator.Generate();
public string GenerateToken(int length)
{
    using (RNGCryptoServiceProvider cryptRNG = new RNGCryptoServiceProvider())
    {
        byte[] tokenBuffer = new byte[length];
        cryptRNG.GetBytes(tokenBuffer);
        return Convert.ToBase64String(tokenBuffer);
    }
}
    //Symb array
    private const string _SymbolsAll = "~`!@#$%^&*()_+=-\\|[{]}'\";:/?.>,<";

    //Random symb
    public string GetSymbol(int Length)
    {
        Random Rand = new Random(DateTime.Now.Millisecond);
        StringBuilder result = new StringBuilder();
        for (int i = 0; i < Length; i++)
            result.Append(_SymbolsAll[Rand.Next(0, _SymbolsAll.Length)]);
        return result.ToString();
    }
using KeePassLib.Cryptography.PasswordGenerator;
using KeePassLib.Security;


public static string GeneratePassword(int passwordLength, bool lowerCase, bool upperCase, bool digits,
        bool punctuation, bool brackets, bool specialAscii, bool excludeLookAlike)
    {
        var ps = new ProtectedString();
        var profile = new PwProfile();
        profile.CharSet = new PwCharSet();
        profile.CharSet.Clear();

        if (lowerCase)
            profile.CharSet.AddCharSet('l');
        if(upperCase)
            profile.CharSet.AddCharSet('u');
        if(digits)
            profile.CharSet.AddCharSet('d');
        if (punctuation)
            profile.CharSet.AddCharSet('p');
        if (brackets)
            profile.CharSet.AddCharSet('b');
        if (specialAscii)
            profile.CharSet.AddCharSet('s');

        profile.ExcludeLookAlike = excludeLookAlike;
        profile.Length = (uint)passwordLength;
        profile.NoRepeatingCharacters = true;

        KeePassLib.Cryptography.PasswordGenerator.PwGenerator.Generate(out ps, profile, null, _pool);

        return ps.ReadString();
    }
    public string GeneratePassword(int len)
    {
        string res = "";
        Random rnd = new Random();
        while (res.Length < len) res += (new Func<Random, string>((r) => {
            char c = (char)((r.Next(123) * DateTime.Now.Millisecond % 123)); 
            return (Char.IsLetterOrDigit(c)) ? c.ToString() : ""; 
        }))(rnd);
        return res;
    }
public string Sifre_Uret(int boy, int noalfa)
{

    //  01.03.2016   
    // Genel amaçlı şifre üretme fonksiyonu


    //Fonskiyon 128 den büyük olmasına izin vermiyor.
    if (boy > 128 ) { boy = 128; }
    if (noalfa > 128) { noalfa = 128; }
    if (noalfa > boy) { noalfa = boy; }


    string passch = System.Web.Security.Membership.GeneratePassword(boy, noalfa);

    //URL encoding ve Url Pass + json sorunu yaratabilecekler pass ediliyor.
    //Microsoft Garanti etmiyor. Alfa Sayısallar Olabiliyorimiş . !@#$%^&*()_-+=[{]};:<>|./?.
    //https://msdn.microsoft.com/tr-tr/library/system.web.security.membership.generatepassword(v=vs.110).aspx


    //URL ve Json ajax lar için filtreleme
    passch = passch.Replace(":", "z");
    passch = passch.Replace(";", "W");
    passch = passch.Replace("'", "t");
    passch = passch.Replace("\"", "r");
    passch = passch.Replace("/", "+");
    passch = passch.Replace("\\", "e");

    passch = passch.Replace("?", "9");
    passch = passch.Replace("&", "8");
    passch = passch.Replace("#", "D");
    passch = passch.Replace("%", "u");
    passch = passch.Replace("=", "4");
    passch = passch.Replace("~", "1");

    passch = passch.Replace("[", "2");
    passch = passch.Replace("]", "3");
    passch = passch.Replace("{", "g");
    passch = passch.Replace("}", "J");


    //passch = passch.Replace("(", "6");
    //passch = passch.Replace(")", "0");
    //passch = passch.Replace("|", "p");
    //passch = passch.Replace("@", "4");
    //passch = passch.Replace("!", "u");
    //passch = passch.Replace("$", "Z");
    //passch = passch.Replace("*", "5");
    //passch = passch.Replace("_", "a");

    passch = passch.Replace(",", "V");
    passch = passch.Replace(".", "N");
    passch = passch.Replace("+", "w");
    passch = passch.Replace("-", "7");





    return passch;



}
private string RandomPassword(int length, bool includeCharacters, bool includeNumbers, bool includeUppercase, bool includeNonAlphaNumericCharacters, bool includeLookAlikes)
{
    if (length < 8 || length > 128) throw new ArgumentOutOfRangeException("length");
    if (!includeCharacters && !includeNumbers && !includeNonAlphaNumericCharacters) throw new ArgumentException("RandomPassword-Key arguments all false, no values would be returned");

    string pw = "";
    do
    {
        pw += System.Web.Security.Membership.GeneratePassword(128, 25);
        pw = RemoveCharacters(pw, includeCharacters, includeNumbers, includeUppercase, includeNonAlphaNumericCharacters, includeLookAlikes);
    } while (pw.Length < length);

    return pw.Substring(0, length);
}

private string RemoveCharacters(string passwordString, bool includeCharacters, bool includeNumbers, bool includeUppercase, bool includeNonAlphaNumericCharacters, bool includeLookAlikes)
{
    if (!includeCharacters)
    {
        var remove = new string[] { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };
        foreach (string r in remove)
        {
            passwordString = passwordString.Replace(r, string.Empty);
            passwordString = passwordString.Replace(r.ToUpper(), string.Empty);
        }
    }

    if (!includeNumbers)
    {
        var remove = new string[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
        foreach (string r in remove)
            passwordString = passwordString.Replace(r, string.Empty);
    }

    if (!includeUppercase)
        passwordString = passwordString.ToLower();

    if (!includeNonAlphaNumericCharacters)
    {
        var remove = new string[] { "!", "@", "#", "$", "%", "^", "&", "*", "(", ")", "-", "_", "+", "=", "{", "}", "[", "]", "|", "\\", ":", ";", "<", ">", "/", "?", "." };
        foreach (string r in remove)
            passwordString = passwordString.Replace(r, string.Empty);
    }

    if (!includeLookAlikes)
    {
        var remove = new string[] { "(", ")", "0", "O", "o", "1", "i", "I", "l", "|", "!", ":", ";" };
        foreach (string r in remove)
            passwordString = passwordString.Replace(r, string.Empty);
    }

    return passwordString;
}
string validChars = String.Join("", Enumerable.Range(33, (126 - 33)).Where(i => !(new int[] { 34, 38, 39, 44, 60, 62, 96 }).Contains(i)).Select(i => { return (char)i; }));
string.Join("", Enumerable.Range(1, 12).Select(i => { return validChars[(new Random(Guid.NewGuid().GetHashCode())).Next(0, validChars.Length - 1)]; }))
 Generate random password of specified length with 
  - Special characters   
  - Number
  - Lowecase
  - Uppercase

  public static string CreatePassword(int length = 12)
    {
        const string lower = "abcdefghijklmnopqrstuvwxyz";
        const string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        const string number = "1234567890";
        const string special = "!@#$%^&*";

        var middle = length / 2;
        StringBuilder res = new StringBuilder();
        Random rnd = new Random();
        while (0 < length--)
        {
            if (middle == length)
            {
                res.Append(number[rnd.Next(number.Length)]);
            }
            else if (middle - 1 == length)
            {
                res.Append(special[rnd.Next(special.Length)]);
            }
            else
            {
                if (length % 2 == 0)
                {
                    res.Append(lower[rnd.Next(lower.Length)]);
                }
                else
                {
                    res.Append(upper[rnd.Next(upper.Length)]);
                }
            }
        }
        return res.ToString();
    }
public static string GeneratePassword(int passLength) {
        var chars = "abcdefghijklmnopqrstuvwxyz@#$&ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        var random = new Random();
        var result = new string(
            Enumerable.Repeat(chars, passLength)
                      .Select(s => s[random.Next(s.Length)])
                      .ToArray());
        return result;
    }
public static class PasswordGenerator
{
    private readonly static Random _rand = new Random();

    public static string Generate(int length = 24)
    {
        const string lower = "abcdefghijklmnopqrstuvwxyz";
        const string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        const string number = "1234567890";
        const string special = "!@#$%^&*_-=+";

        // Get cryptographically random sequence of bytes
        var bytes = new byte[length];
        new RNGCryptoServiceProvider().GetBytes(bytes);

        // Build up a string using random bytes and character classes
        var res = new StringBuilder();
        foreach(byte b in bytes)
        {
            // Randomly select a character class for each byte
            switch (_rand.Next(4))
            {
                // In each case use mod to project byte b to the correct range
                case 0:
                    res.Append(lower[b % lower.Count()]);
                    break;
                case 1:
                    res.Append(upper[b % upper.Count()]);
                    break;
                case 2:
                    res.Append(number[b % number.Count()]);
                    break;
                case 3:
                    res.Append(special[b % special.Count()]);
                    break;
            }
        }
        return res.ToString();
    }
}
PasswordGenerator.Generate(12)
"pzY=64@-ChS$"
"BG0OsyLbYnI_"
"l9#5^2&adj_i"
"#++Ws9d$%O%X"
"IWhdIN-#&O^s"
switch (_rand.Next(6))
{
    // Prefer letters 2:1
    case 0:
    case 1:
        res.Append(lower[b % lower.Count()]);
        break;
    case 2:
    case 3:
        res.Append(upper[b % upper.Count()]);
        break;
    case 4:
        res.Append(number[b % number.Count()]);
        break;
    case 5:
        res.Append(special[b % special.Count()]);
        break;
}
public static string GeneratePassword(int Length, int NonAlphaNumericChars)
    {
        string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
        string allowedNonAlphaNum = "!@#$%^&*()_-+=[{]};:<>|./?";
        string pass = "";
        Random rd = new Random(DateTime.Now.Millisecond);
        for (int i = 0; i < Length; i++)
        {
            if (rd.Next(1) > 0 && NonAlphaNumericChars > 0)
            {
                pass += allowedNonAlphaNum[rd.Next(allowedNonAlphaNum.Length)];
                NonAlphaNumericChars--;
            }
            else
            {
                pass += allowedChars[rd.Next(allowedChars.Length)];
            }
        }
        return pass;
    }
var pwd = new Password().IncludeLowercase().IncludeUppercase().IncludeSpecial();
var password = pwd.Next();
static string GeneratePassword(int characterCount)
{
    string password = String.Empty;
    while(password.Length < characterCount)
        password += Regex.Replace(System.Web.Security.Membership.GeneratePassword(128, 0), "[^a-zA-Z0-9]", string.Empty);
    return password.Substring(0, characterCount);
}
 public string GeneratePassword(int length)
    {

        RNGCryptoServiceProvider cryptRNG = new RNGCryptoServiceProvider();
        byte[] tokenBuffer = new byte[length];
        cryptRNG.GetBytes(tokenBuffer);
        return Convert.ToBase64String(tokenBuffer).Remove(length);
                  
    }
using System;
using System.Linq;

public class Program
{
    private static Random random = new Random();
    public static void Main()
    {
        Console.WriteLine("Random password with length of 8 character.");
        Console.WriteLine("===========================================");
        Console.WriteLine("Capital latters : 2");
        Console.WriteLine("Number latters : 2");
        Console.WriteLine("Special latters : 2");
        Console.WriteLine("Small latters : 2");
        Console.WriteLine("===========================================");
        Console.Write("The Random Password : ");
        Console.WriteLine(RandomStringCap(2) + RandomStringNum(2) + RandomStringSpe(2) + RandomStringSml(2));
        Console.WriteLine("===========================================");
    }
    public static string RandomStringCap(int length)
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        return new string(Enumerable.Repeat(chars, length)
                         .Select(s => s[random.Next(s.Length)]).ToArray());
    }
    public static string RandomStringNum(int length)
    {
        const string chars = "0123456789";
        return new string(Enumerable.Repeat(chars, length)
                         .Select(s => s[random.Next(s.Length)]).ToArray());
    }
    public static string RandomStringSml(int length)
    {
        const string chars = "abcdefghijklmnopqrstuvwxyz";
        return new string(Enumerable.Repeat(chars, length)
                         .Select(s => s[random.Next(s.Length)]).ToArray());
    }
    public static string RandomStringSpe(int length)
    {
        const string chars = "!@#$%^&*_-=+";
        return new string(Enumerable.Repeat(chars, length)
                         .Select(s => s[random.Next(s.Length)]).ToArray());
    }
}