Develop Reference

repeating the Encrypt function along the length of the bina function

I want to repeat the Encrypt function along the entire length of the bina / how to do it?
private void carbonFiberButton11_Click_1(object sender, EventArgs e)
{
textBox1.Text = PairConcat(Encrypt(), bina());
}
public static string PairConcat(string Encrypt, string bina)
{
StringBuilder result = new StringBuilder();
int i = 0;
for(; i<Encrypt.Length & i < bina.Length; i++)
{
result.Append(Encrypt[i].ToString());
result.Append(bina[i].ToString());
}
result.Append(Encrypt.Substring(i));
result.Append(bina.Substring(i));
return result.ToString();
}
For example:
string bina = "1234567";
string Encrypt = "abcdefg";
textbox1.text = 1a2b3c4d.. ;but it is doesn't works if I have different length:
string bina = "12345"
string Encrypt = "abc"
textbox1.text = 1a2b3c45 , but I need - 1a2b3c4a5b.
Encrypt function:
string Encrypt() //random to binary
{
var encrypt = textBox4.Text;
StringBuilder binary = new StringBuilder();
for (int i = 0; i < encrypt.Length; i++)
{
binary.Append(Convert.ToString(encrypt[i], 2).PadLeft(8, '0'));
}
return binary.ToString();
}
I can't understand what to do/ Help me, please

Just make the Encrypt string in minimum as long as the bina string.
// Calculate smallest multiple of Encrypt.Length at least as long as bina.Length
int lb = bina.Length;
int le = Encrypt.Length;
int bufferLength = (lb + le - 1) / le * le;
var sb = new StringBuilder(Encrypt, bufferLength);
while (sb.Length < lb) {
sb.Append(Encrypt);
}
Encrypt = sb.ToString();
string result = String.Join("", bina.Zip(Encrypt, (a, b) => a.ToString() + b));
The LINQ Zip method combines 2 sequences by providing pairs of items from the two sequences until one sequence ends. Here the sequences consist of chars.
The StringBuilder works most efficiently if does not have to resize its internal buffer. I calculate it by using integer arithmetic.

Random is not working good

I generate a string with 62 options ^ 6 letters = 56,800,235,584
But when running the code, it repeats the same string less then every 200,200 times
What is the problem here?
BTW:
This code is based on the answer here
class Program
{
static void Main(string[] args)
{
var d = new Dictionary<string, bool>();
for (int i = 0; ; i++)
{
var s = GenerateString(6);
try
{
d.Add(s, false);
}
catch (Exception ex)
{
Console.WriteLine(String.Format("{0} - {1} - {2}", i, s, ex.Message));
i = 0;
}
}
Console.ReadKey();
}
static Random _rnd = new Random();
public static string GenerateString(int len)
{
const string bigLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const string smallLetters = "abcdefghijklmnopqrstuvwxyz";
const string numbers = "1234567890";
var validChars = bigLetters + smallLetters + numbers;
var result = new StringBuilder();
for (int i = 0; i < len; i++)
{
result.Append(validChars[_rnd.Next(validChars.Length)]);
}
return result.ToString();
}
}

There is all OK with random.
The problem is related with Birthday paradox. When you have 200k items one of them could repeat.
Random string doesnt garantee always unique result. For unique results you should use GUID's.

To avoid repeatation you can do a check for existence before adding the string to the list:
After for loop in GenerateString()
if(d.Contains(result.ToString()) // check whether the current generated string is in the list
{
GenerateString(len); // if it is already existed generate another one
}
else
{
return result.ToString(); // if not then return the string
}

C# Guessing Game using a text file

I'm trying to create a word guessing game that uses a dictionary text file. The game is supposed to take input from the user on how long the word should be before asking them to guess the word. If the user fails to guess after 3 times then it reveals the answer. I used a list on recommendation from a friend to read from the dictionary as it is quite large.
My question is, how can I read the list to choose a word for the guessing game?
{
static int letterLength, LettersLeft, wrongGuess;
public static void Main(string[] args)
{
string input = System.IO.File.ReadAllText("dictionary.txt");
string[] terms = input.Split();
List<string> list = new List<string>();
for (int num = 0; num < terms.Length; num++)
list.Add(terms[num]);
int wordToGuess = GetLengthOfWordToGuess();
List<string> fixedlist = new List<string>();
for (int num = 0; num < list.Count; num++)
{
string tempword = list[num];
if (tempword.Length == wordToGuess)
fixedlist.Add(tempword);
}
for (int num = 0; num < fixedlist.Count; num++)
Console.WriteLine(fixedlist[num]);
Console.WriteLine("Welcome to the guessing game");
letterLength = GetLengthOfWordToGuess();
Console.Clear();
//Not Working from here on.
string wordGuess = GetWordToGuess();
char[] maskedWord = GetHiddenLetters(wordGuess, '-');
LettersLeft = wordGuess.Length;
char userGuess;
wrongGuess = 3;
while (wrongGuess > 0 && LettersLeft > 0)
{
DispayCharacters(maskedWord);
Console.WriteLine("Enter a Letter");
userGuess = char.Parse(Console.ReadLine());
maskedWord = CheckGuess(userGuess, wordGuess, maskedWord);
}
Console.WriteLine("Well done! Thanks for Playing.");
Console.ReadLine();
}
static string GetWordToGuess()
{
Random word = new Random();
int wordNumber = word.Next(0, 9);
string[] words = { "" };
string selectWord = words[wordNumber];
return selectWord;
}
static char [] GetHiddenLetters(string word, char mask)
{
char[] hidden = new char[word.Length];
for (int i = 0; i < word.Length; i++)
{
hidden[i] = mask;
}
return hidden;
}
static void DispayCharacters(char [] characters)
{
foreach(char letter in characters)
{
Console.Write(letter);
Console.WriteLine();
}
}
static int GetLengthOfWordToGuess()
{
Console.WriteLine("Input length of word to guess");
int selectWord = int.Parse(Console.ReadLine());
return selectWord;
}
static char [] CheckGuess (char letterToCheck, string word, char [] characters)
{
bool wrong = true;
if(wrongGuess > 0)
{
for (int i = 0; i < word.Length; i++)
{
if (word[i] == letterToCheck)
{
characters[i] = word[i];
LettersLeft--;
wrong = false;
}
}
}
}
}

One major problem I see up front is that your GetWordToGuess function is not functional and probably throws an IndexOutOfRangeException.
The reason for that is that you are instantiating the words array as an array with a single empty string in it, but you are then referencing an index between 0 and 9, which will not exist in that array unless the random number generated is 0.
To solve this you should pass the fixedlist List you already created and use that instead of the words array. You should make sure to generate a random number between 0 and fixedlist.Count-1 so that you don't hit that same out of range exception. Therefore that function should look something like this:
static string GetWordToGuess(List<string> fixedlist)
{
Random word = new Random();
int wordNumber = word.Next(0, 9);
string[] words = { "" };
string selectWord = words[wordNumber];
return selectWord;
}
Also, as it stands right now, your included code doesn't compile because the CheckGuess function doesn't return a char[] as it says it should. I believe what you meant to do was have a return characters; line at the end (this was probably just a copy paste issue when you put your code in your question, but I thought I'd mention it just in case).
As a side note there are a number of small issues with your code like declaring things you don't use, but since they don't break your program I didn't want to go through and fix them.

Generate password using a for loop

I am making a password generator that generates a random number, then I have it converted to a letter using ascii. Inside the for loop, I need the letters to convert a string instead of a list. It works, but it just displays random letters as a list.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
class MainClass
{
static void Main()
{
int x = 1;
int length;
string a = "Press any key to continue";
object num;
while (x == 1)
{
Console.WriteLine("How many Characters would you like the Password to be? (Press -1 to Stop)");
length = Convert.ToInt32(Console.ReadLine());
try
{
for (int i = 0; i < length; i++)
{
int num1 = Number();
Int32 ASCII = num1;
num = (char)num1;
if (length > 0)
{
Console.WriteLine(num);
}
}
}
catch
{
Console.WriteLine(a);
}
if (length == -1)
break;
}
}
static Random _r = new Random();
static int Number()
{
return _r.Next(65, 90); // decimal
}
}

StringBuilder sb = new StringBuilder();
for( int i = 0; i < length; i++ )
{
int num1 = Number();
Int32 ASCII = num1;
num = (char)num1;
sb.Append( num );
}
Console.WriteLine( sb.ToString() );
This isn't how I would build a password nor how I would generate random text, but this will give you a string and answer the original question.
As to how I would do this task:
System.Security.Cryptography.RNGCryptoServiceProvider _crypto = new System.Security.Cryptography.RNGCryptoServiceProvider();
byte[] bytes = new byte[8]; // this array can be larger if desired
_crypto.GetBytes( bytes );
ulong randomNumber = (ulong)BitConverter.ToInt64( bytes, 0 );
// convert to a string with the encoding of your choice; I prefer Base 62
For completeness sake, here's a Base62 algorithm which I use. Base62 has the advantage over the more commonly-used Base64 in that it does not include any special characters so it is easy to use in query strings, HTML, and JavaScript (with a few minor caveats). Of course, passwords shouldn't be used in any of those places, and you may want to include special characters to make a password more complex.
Regardless, here is how I convert random numbers to Base62.
private static readonly char[] _base62Characters = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
public static string ToBase62String( long value )
{
if( value < 0L )
{
throw new ArgumentException( "Number must be zero or greater." );
}
if( value == 0 )
{
return "0";
}
string retVal = "";
while( value > 0 )
{
retVal = _base62Characters[value % 62] + retVal;
value = value / 62;
}
return retVal;
}
Lastly, I want to point out that passwords should very rarely be generated for any purpose, because that means they are being distributed in some form. Passwords should be hashed and salted; password resets should rely on random, expiring security tokens allowing the user a one-time reset. Passwords should never be emailed to a user; passwords should never be stored in plaintext or any reversible format.
For password reset token generation, the code I provided could work nicely because it produces a large, cryptographically random number encoded with a web-safe format. But even a hashed GUID would do the trick in that case.

var sb = new StringBuilder();
for (int i = 0; i < length; i++) {
sb.Append((char)Number());
}
string password = sb.ToString();
Console.WriteLine(password );
But I would change your Number() method to:
private static char GetRandomChar()
{
return (char)_r.Next(65, 90);
}
and then replace the line inside the loop:
sb.Append(GetRandomChar());

//You have to append the values generated by the RandomNumber in to your password variable
class MainClass
{
static void Main()
{
int x = 1;
int length;
string a = "Press any key to continue";
string num=string.Empty;
while (x == 1)
{
Console.WriteLine("How many Characters would you like the Password to be? (Press -1 to Stop)");
length = Convert.ToInt32(Console.ReadLine());
try
{
for (int i = 0; i < length; i++)
{
int num1 = Number();
Int32 ASCII = num1;
num =num+ ((char)num1);
}
Console.WriteLine(num);
}
catch
{
Console.WriteLine(a);
}
if (length == -1)
break;
}
}
static Random _r = new Random();
static int Number()
{
return _r.Next(65, 90); // decimal
}
}

you can try this one
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace PasswordSample
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Generated password: {0}", GeneratePassword(12, true));
}
/// <summary>
/// Generate a random password
/// </summary>
/// <param name="pwdLenght">Password lenght</param>
/// <param name="nonAlphaNumericChars">Indicates if password will include non alpha-numeric</param>
/// <returns>Return a password</returns>
private static String GeneratePassword(int pwdLenght, bool nonAlphaNumericChars)
{
// Allowed characters
String allowedChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
if (nonAlphaNumericChars)
{
// Add non-alphanumeric chars
allowedChars += "-&##%!*$?_";
}
char[] passwordChars = new char[pwdLenght];
Random rnd = new Random();
// Generate a random password
for (int i = 0; i < pwdLenght; i++)
passwordChars[i] = allowedChars[rnd.Next(0, allowedChars.Length)];
return new String(passwordChars);
}
}
}

just define a string at near int x...
like
String Password = "";
and in the if statement appent the keyyword.
if (length > 0)
{
Console.WriteLine(num);
Password+=num
}

I found the following post useful when I had to create a method to generate a random password:
https://stackoverflow.com/a/730352/1015289
However, when I wanted to create a short 'validation' style code which would be emailed to a user to confirm their details, I wanted to restrict the validation code to only 8 characters.
For this I used the following:
string validationCoce = Guid.NewGuid().ToString().Substring(0, 8);
This would be stored in a database which also held the users email, both encrypted before being stored for security purposes.
Both the email and validation code were required to validate the users account.
Hope either of the above help?
Kind Regards, Wayne

use Console.Write() instead of Console.WriteLine() otherwise append to some string and print outside the loop

Generating Random Passwords

When a user on our site loses his password and heads off to the Lost Password page we need to give him a new temporary password. I don't really mind how random this is, or if it matches all the "needed" strong password rules, all I want to do is give them a password that they can change later.
The application is a Web application written in C#. so I was thinking of being mean and going for the easy route of using part of a Guid. i.e.
Guid.NewGuid().ToString("d").Substring(1,8)
Suggesstions? thoughts?

There's always System.Web.Security.Membership.GeneratePassword(int length, int numberOfNonAlphanumericCharacters).

public string CreatePassword(int length)
{
const string valid = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
StringBuilder res = new StringBuilder();
Random rnd = new Random();
while (0 < length--)
{
res.Append(valid[rnd.Next(valid.Length)]);
}
return res.ToString();
}
This has a good benefit of being able to choose from a list of available characters for the generated password (e.g. digits only, only uppercase or only lowercase etc.)

The main goals of my code are:
The distribution of strings is almost uniform (don't care about minor deviations, as long as they're small)
It outputs more than a few billion strings for each argument set. Generating an 8 character string (~47 bits of entropy) is meaningless if your PRNG only generates 2 billion (31 bits of entropy) different values.
It's secure, since I expect people to use this for passwords or other security tokens.
The first property is achieved by taking a 64 bit value modulo the alphabet size. For small alphabets (such as the 62 characters from the question) this leads to negligible bias. The second and third property are achieved by using RNGCryptoServiceProvider instead of System.Random.
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);
}
(This is a copy of my answer to How can I generate random 8 character, alphanumeric strings in C#?)

public string GenerateToken(int length)
{
using (RNGCryptoServiceProvider cryptRNG = new RNGCryptoServiceProvider())
{
byte[] tokenBuffer = new byte[length];
cryptRNG.GetBytes(tokenBuffer);
return Convert.ToBase64String(tokenBuffer);
}
}
(You could also have the class where this method lives implement IDisposable, hold a reference to the RNGCryptoServiceProvider, and dispose of it properly, to avoid repeatedly instantiating it.)
It's been noted that as this returns a base-64 string, the output length is always a multiple of 4, with the extra space using = as a padding character. The length parameter specifies the length of the byte buffer, not the output string (and is therefore perhaps not the best name for that parameter, now I think about it). This controls how many bytes of entropy the password will have. However, because base-64 uses a 4-character block to encode each 3 bytes of input, if you ask for a length that's not a multiple of 3, there will be some extra "space", and it'll use = to fill the extra.
If you don't like using base-64 strings for any reason, you can replace the Convert.ToBase64String() call with either a conversion to regular string, or with any of the Encoding methods; eg. Encoding.UTF8.GetString(tokenBuffer) - just make sure you pick a character set that can represent the full range of values coming out of the RNG, and that produces characters that are compatible with wherever you're sending or storing this. Using Unicode, for example, tends to give a lot of Chinese characters. Using base-64 guarantees a widely-compatible set of characters, and the characteristics of such a string shouldn't make it any less secure as long as you use a decent hashing algorithm.

This is a lot larger, but I think it looks a little more comprehensive:
http://www.obviex.com/Samples/Password.aspx
///////////////////////////////////////////////////////////////////////////////
// SAMPLE: Generates random password, which complies with the strong password
// rules and does not contain ambiguous characters.
//
// To run this sample, create a new Visual C# project using the Console
// Application template and replace the contents of the Class1.cs file with
// the code below.
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
// EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
//
// Copyright (C) 2004 Obviex(TM). All rights reserved.
//
using System;
using System.Security.Cryptography;
/// <summary>
/// This class can generate random passwords, which do not include ambiguous
/// characters, such as I, l, and 1. The generated password will be made of
/// 7-bit ASCII symbols. Every four characters will include one lower case
/// character, one upper case character, one number, and one special symbol
/// (such as '%') in a random order. The password will always start with an
/// alpha-numeric character; it will not start with a special symbol (we do
/// this because some back-end systems do not like certain special
/// characters in the first position).
/// </summary>
public class RandomPassword
{
// Define default min and max password lengths.
private static int DEFAULT_MIN_PASSWORD_LENGTH = 8;
private static int DEFAULT_MAX_PASSWORD_LENGTH = 10;
// Define supported password characters divided into groups.
// You can add (or remove) characters to (from) these groups.
private static string PASSWORD_CHARS_LCASE = "abcdefgijkmnopqrstwxyz";
private static string PASSWORD_CHARS_UCASE = "ABCDEFGHJKLMNPQRSTWXYZ";
private static string PASSWORD_CHARS_NUMERIC= "23456789";
private static string PASSWORD_CHARS_SPECIAL= "*$-+?_&=!%{}/";
/// <summary>
/// Generates a random password.
/// </summary>
/// <returns>
/// Randomly generated password.
/// </returns>
/// <remarks>
/// The length of the generated password will be determined at
/// random. It will be no shorter than the minimum default and
/// no longer than maximum default.
/// </remarks>
public static string Generate()
{
return Generate(DEFAULT_MIN_PASSWORD_LENGTH,
DEFAULT_MAX_PASSWORD_LENGTH);
}
/// <summary>
/// Generates a random password of the exact length.
/// </summary>
/// <param name="length">
/// Exact password length.
/// </param>
/// <returns>
/// Randomly generated password.
/// </returns>
public static string Generate(int length)
{
return Generate(length, length);
}
/// <summary>
/// Generates a random password.
/// </summary>
/// <param name="minLength">
/// Minimum password length.
/// </param>
/// <param name="maxLength">
/// Maximum password length.
/// </param>
/// <returns>
/// Randomly generated password.
/// </returns>
/// <remarks>
/// The length of the generated password will be determined at
/// random and it will fall with the range determined by the
/// function parameters.
/// </remarks>
public static string Generate(int minLength,
int maxLength)
{
// Make sure that input parameters are valid.
if (minLength <= 0 || maxLength <= 0 || minLength > maxLength)
return null;
// Create a local array containing supported password characters
// grouped by types. You can remove character groups from this
// array, but doing so will weaken the password strength.
char[][] charGroups = new char[][]
{
PASSWORD_CHARS_LCASE.ToCharArray(),
PASSWORD_CHARS_UCASE.ToCharArray(),
PASSWORD_CHARS_NUMERIC.ToCharArray(),
PASSWORD_CHARS_SPECIAL.ToCharArray()
};
// Use this array to track the number of unused characters in each
// character group.
int[] charsLeftInGroup = new int[charGroups.Length];
// Initially, all characters in each group are not used.
for (int i=0; i<charsLeftInGroup.Length; i++)
charsLeftInGroup[i] = charGroups[i].Length;
// Use this array to track (iterate through) unused character groups.
int[] leftGroupsOrder = new int[charGroups.Length];
// Initially, all character groups are not used.
for (int i=0; i<leftGroupsOrder.Length; i++)
leftGroupsOrder[i] = i;
// Because we cannot use the default randomizer, which is based on the
// current time (it will produce the same "random" number within a
// second), we will use a random number generator to seed the
// randomizer.
// Use a 4-byte array to fill it with random bytes and convert it then
// to an integer value.
byte[] randomBytes = new byte[4];
// Generate 4 random bytes.
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
rng.GetBytes(randomBytes);
// Convert 4 bytes into a 32-bit integer value.
int seed = BitConverter.ToInt32(randomBytes, 0);
// Now, this is real randomization.
Random random = new Random(seed);
// This array will hold password characters.
char[] password = null;
// Allocate appropriate memory for the password.
if (minLength < maxLength)
password = new char[random.Next(minLength, maxLength+1)];
else
password = new char[minLength];
// Index of the next character to be added to password.
int nextCharIdx;
// Index of the next character group to be processed.
int nextGroupIdx;
// Index which will be used to track not processed character groups.
int nextLeftGroupsOrderIdx;
// Index of the last non-processed character in a group.
int lastCharIdx;
// Index of the last non-processed group.
int lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;
// Generate password characters one at a time.
for (int i=0; i<password.Length; i++)
{
// If only one character group remained unprocessed, process it;
// otherwise, pick a random character group from the unprocessed
// group list. To allow a special character to appear in the
// first position, increment the second parameter of the Next
// function call by one, i.e. lastLeftGroupsOrderIdx + 1.
if (lastLeftGroupsOrderIdx == 0)
nextLeftGroupsOrderIdx = 0;
else
nextLeftGroupsOrderIdx = random.Next(0,
lastLeftGroupsOrderIdx);
// Get the actual index of the character group, from which we will
// pick the next character.
nextGroupIdx = leftGroupsOrder[nextLeftGroupsOrderIdx];
// Get the index of the last unprocessed characters in this group.
lastCharIdx = charsLeftInGroup[nextGroupIdx] - 1;
// If only one unprocessed character is left, pick it; otherwise,
// get a random character from the unused character list.
if (lastCharIdx == 0)
nextCharIdx = 0;
else
nextCharIdx = random.Next(0, lastCharIdx+1);
// Add this character to the password.
password[i] = charGroups[nextGroupIdx][nextCharIdx];
// If we processed the last character in this group, start over.
if (lastCharIdx == 0)
charsLeftInGroup[nextGroupIdx] =
charGroups[nextGroupIdx].Length;
// There are more unprocessed characters left.
else
{
// Swap processed character with the last unprocessed character
// so that we don't pick it until we process all characters in
// this group.
if (lastCharIdx != nextCharIdx)
{
char temp = charGroups[nextGroupIdx][lastCharIdx];
charGroups[nextGroupIdx][lastCharIdx] =
charGroups[nextGroupIdx][nextCharIdx];
charGroups[nextGroupIdx][nextCharIdx] = temp;
}
// Decrement the number of unprocessed characters in
// this group.
charsLeftInGroup[nextGroupIdx]--;
}
// If we processed the last group, start all over.
if (lastLeftGroupsOrderIdx == 0)
lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;
// There are more unprocessed groups left.
else
{
// Swap processed group with the last unprocessed group
// so that we don't pick it until we process all groups.
if (lastLeftGroupsOrderIdx != nextLeftGroupsOrderIdx)
{
int temp = leftGroupsOrder[lastLeftGroupsOrderIdx];
leftGroupsOrder[lastLeftGroupsOrderIdx] =
leftGroupsOrder[nextLeftGroupsOrderIdx];
leftGroupsOrder[nextLeftGroupsOrderIdx] = temp;
}
// Decrement the number of unprocessed groups.
lastLeftGroupsOrderIdx--;
}
}
// Convert password characters into a string and return the result.
return new string(password);
}
}
/// <summary>
/// Illustrates the use of the RandomPassword class.
/// </summary>
public class RandomPasswordTest
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// Print 100 randomly generated passwords (8-to-10 char long).
for (int i=0; i<100; i++)
Console.WriteLine(RandomPassword.Generate(8, 10));
}
}
//
// END OF FILE
///////////////////////////////////////////////////////////////////////////////

I created this class that uses RNGCryptoServiceProvider and it is flexible. Example:
var generator = new PasswordGenerator(minimumLengthPassword: 8,
maximumLengthPassword: 15,
minimumUpperCaseChars: 2,
minimumNumericChars: 3,
minimumSpecialChars: 2);
string password = generator.Generate();

I know that this is an old thread, but I have what might be a fairly simple solution for someone to use. Easy to implement, easy to understand, and easy to validate.
Consider the following requirement:
I need a random password to be generated which has at least 2 lower-case letters, 2 upper-case letters and 2 numbers. The password must also be a minimum of 8 characters in length.
The following regular expression can validate this case:
^(?=\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,}$
It's outside the scope of this question - but the regex is based on lookahead/lookbehind and lookaround.
The following code will create a random set of characters which match this requirement:
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);
}
To meet the above requirement, simply call the following:
String randomPassword = GeneratePassword(3, 3, 3);
The code starts with an invalid character ("!") - so that the string has a length into which new characters can be injected.
It then loops from 1 to the # of lowercase characters required, and on each iteration, grabs a random item from the lowercase list, and injects it at a random location in the string.
It then repeats the loop for uppercase letters and for numerics.
This gives you back strings of length = lowercase + uppercase + numerics into which lowercase, uppercase and numeric characters of the count you want have been placed in a random order.

I'll add another ill-advised answer to the pot.
I have a use case where I need random passwords for machine-machine communication, so I don't have any requirement for human readability. I also don't have access to Membership.GeneratePassword in my project, and don't want to add the dependency.
I am fairly certain Membership.GeneratePassword is doing something similar to this, but here you can tune the pools of characters to draw from.
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 = "!##$%^&*_-=+";
// Get cryptographically random sequence of bytes
var bytes = new byte[length];
new RNGCryptoServiceProvider().GetBytes(bytes);
// Build up a string using random bytes and character classes
var res = new StringBuilder();
foreach(byte b in bytes)
{
// Randomly select a character class for each byte
switch (_rand.Next(4))
{
// In each case use mod to project byte b to the correct range
case 0:
res.Append(lower[b % lower.Count()]);
break;
case 1:
res.Append(upper[b % upper.Count()]);
break;
case 2:
res.Append(number[b % number.Count()]);
break;
case 3:
res.Append(special[b % special.Count()]);
break;
}
}
return res.ToString();
}
}
And some example output:
PasswordGenerator.Generate(12)
"pzY=64#-ChS$"
"BG0OsyLbYnI_"
"l9#5^2&adj_i"
"#++Ws9d$%O%X"
"IWhdIN-#&O^s"
To preempt complaints about the use of Random: The primary source of randomness is still the crypto RNG. Even if you could deterministically preordain the sequence coming out of Random (say it only produced 1) you still wouldn't know the next char that would be picked (though that would limit the range of possibilities).
One simple extension would be to add weighting to the different character sets, which could be as simple as upping the max value and adding fall-through cases to increase weight.
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;
}
For a more humanistic random password generator I once implemented a prompt system using the EFF dice-word list.

I don't like the passwords that Membership.GeneratePassword() creates, as they're too ugly and have too many special characters.
This code generates a 10 digit not-too-ugly password.
string password = Guid.NewGuid().ToString("N").ToLower()
.Replace("1", "").Replace("o", "").Replace("0","")
.Substring(0,10);
Sure, I could use a Regex to do all the replaces but this is more readable and maintainable IMO.

For this sort of password, I tend to use a system that's likely to generate more easily "used" passwords. Short, often made up of pronouncable fragments and a few numbers, and with no intercharacter ambiguity (is that a 0 or an O? A 1 or an I?). Something like
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;
(Typed right into the browser, so use only as guidelines. Also, add more words).

I created this method similar to the available in the membership provider. This is usefull if you don't want to add the web reference in some applications.
It works great.
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;
}

I've always been very happy with the password generator built-in to KeePass. Since KeePass is a .Net program, and open source, I decided to dig around the code a bit. I ended up just referncing KeePass.exe, the copy provided in the standard application install, as a reference in my project and writing the code below. You can see how flexible it is thanks to KeePass. You can specify length, which characters to include/not include, etc...
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();
}

I like to look at generating passwords, just like generating software keys. You should choose from an array of characters that follow a good practice. Take what #Radu094 answered with and modify it to follow good practice. Don't put every single letter in the character array. Some letters are harder to say or understand over the phone.
You should also consider using a checksum on the password that was generated to make sure that it was generated by you. A good way of accomplishing this is to use the LUHN algorithm.

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;
}

This package allows you to generate a random password while fluently indicating which characters it should contain (if needed):
https://github.com/prjseal/PasswordGenerator/
Example:
var pwd = new Password().IncludeLowercase().IncludeUppercase().IncludeSpecial();
var password = pwd.Next();

If you want to make use of the cryptographically secure random number generation used by System.Web.Security.Membership.GeneratePassword but also want to restrict the character set to alphanumeric characters, you can filter the result with a regex:
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);
}

check this code...
I added the .remove(length) to improve anaximander's response
public string GeneratePassword(int length)
{
using(RNGCryptoServiceProvider cryptRNG = new RNGCryptoServiceProvider();)
{
byte[] tokenBuffer = new byte[length];
cryptRNG.GetBytes(tokenBuffer);
return Convert.ToBase64String(tokenBuffer).Remove(length);
}
}

How to Generate the Random Password in C#.
Output : (https://prnt.sc/11fac8v)
Run : https://onlinegdb.com/HJe5OHBLu
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());
}

Pretty easy way to require one from each group using Random and linq-to-objects.
Randomize each group
Select random amount from first group
Select remaining random amounts from following groups
 
Random rand = new Random();
int min = 8;
int max = 16;
int totalLen = rand.Next(min, max);
int remainingGroups = 4;
string[] allowedLowerChars = "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".Split(',');
string [] allowedUpperChars = "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".Split(',');
string [] allowedNumbers = "1,2,3,4,5,6,7,8,9,0".Split(',');
string [] allowedSpecialChars = "!,#,#,$,%,&,?".Split(',');
var password = allowedLowerChars.OrderBy(c => rand.Next()).Take(rand.Next(1, totalLen-remainingGroups--)).ToList();
password.AddRange(allowedUpperChars.OrderBy(c => rand.Next()).Take(rand.Next(1, totalLen-password.Count-remainingGroups--)).ToList());
password.AddRange(allowedNumbers.OrderBy(c => rand.Next()).Take(rand.Next(1, totalLen-password.Count-remainingGroups--)).ToList());
password.AddRange(allowedSpecialChars.OrderBy(c => rand.Next()).Take(totalLen-password.Count).ToList());
password = password.OrderBy(c => rand.Next()).ToList(); // randomize groups

Inspired by the answer from #kitsu.eb, but using RandomNumberGenerator instead of Random or RNGCryptoServiceProvider (deprecated in .NET 6), and added a few more special characters.
Optional parameter to exclude characters that will be escaped when using System.Text.Json.JsonSerializer.Serialize - for example & which is escaped as \u0026 - so that you can guarantee the length of the serialized string will match the length of the password.
For .NET Core 3.0 and above.
public static class PasswordGenerator
{
const string lower = "abcdefghijklmnopqrstuvwxyz";
const string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const string number = "1234567890";
const string special = "!##$%^&*()[]{},.:`~_-=+"; // excludes problematic characters like ;'"/\
const string specialJsonSafe = "!##$%^*()[]{},.:~_-="; // excludes problematic characters like ;'"/\ and &`+
const int lowerLength = 26; // lower.Length
const int upperLength = 26; // upper.Length;
const int numberLength = 10; // number.Length;
const int specialLength = 23; // special.Length;
const int specialJsonSafeLength = 20; // specialJsonSafe.Length;
public static string Generate(int length = 96, bool jsonSafeSpecialCharactersOnly = false)
{
Span<char> result = length < 1024 ? stackalloc char[length] : new char[length].AsSpan();
for (int i = 0; i < length; ++i)
{
switch (RandomNumberGenerator.GetInt32(4))
{
case 0:
result[i] = lower[RandomNumberGenerator.GetInt32(0, lowerLength)];
break;
case 1:
result[i] = upper[RandomNumberGenerator.GetInt32(0, upperLength)];
break;
case 2:
result[i] = number[RandomNumberGenerator.GetInt32(0, numberLength)];
break;
case 3:
if (jsonSafeSpecialCharactersOnly)
{
result[i] = specialJsonSafe[RandomNumberGenerator.GetInt32(0, specialJsonSafeLength)];
}
else
{
result[i] = special[RandomNumberGenerator.GetInt32(0, specialLength)];
}
break;
}
}
return result.ToString();
}
}

Since Random is not secure and RNGCryptoServiceProvider is obsolte I ended up doing this:
// possible characters that password can have
private const string passChars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"abcdefghijklmnopqrstuvwxyz" +
"0123456789" +
"!##$%.-_"
;
public static string GetRandomPassword(int length)
{
char[] p = new char[length];
for (int i = 0; i < length; i++)
p[i] = passChars[RandomNumberGenerator.GetInt32(0, passChars.Length)];
return new string(p);
}

Here is a solution that uses RNGCryptoServiceProvider to mimic the functionality of Membership.GeneratePassword from the System.Web.Security namespace.
I needed a drop-in replacement for running it in Azure Function.
It can be tested here:
https://dotnetfiddle.net/V0cNJw
public static string GeneratePassword(int length, int numberOfNonAlphanumericCharacters)
{
const string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
const string nonAlphanumericChars = "!##$%^&*()_-+=[{]};:<>|./?";
var randNum = new byte[4];
using (var rng = new RNGCryptoServiceProvider())
{
rng.GetBytes(randNum);
var randomSeed = BitConverter.ToInt32(randNum, 0);
var random = new Random(randomSeed);
var chars = new char[length];
var allowedCharCount = allowedChars.Length;
var nonAlphanumericCharCount = nonAlphanumericChars.Length;
var numNonAlphanumericCharsAdded = 0;
for (var i = 0; i < length; i++)
{
if (numNonAlphanumericCharsAdded < numberOfNonAlphanumericCharacters && i < length - 1)
{
chars[i] = nonAlphanumericChars[random.Next(nonAlphanumericCharCount)];
numNonAlphanumericCharsAdded++;
}
else
{
chars[i] = allowedChars[random.Next(allowedCharCount)];
}
}
return new string(chars);
}
}
Here is a version that runs on .Net 6.0+
Sandbox: https://dotnetfiddle.net/XqgTSg
public static string GeneratePassword(int length, int numberOfNonAlphanumericCharacters)
{
const string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
const string nonAlphanumericChars = "!##$%^&*()_-+=[{]};:<>|./?";
var randNum = new byte[4];
using (var rng = RandomNumberGenerator.Create())
{
rng.GetBytes(randNum);
var randomSeed = BitConverter.ToInt32(randNum, 0);
var random = new Random(randomSeed);
var chars = new char[length];
var allowedCharCount = allowedChars.Length;
var nonAlphanumericCharCount = nonAlphanumericChars.Length;
var numNonAlphanumericCharsAdded = 0;
for (var i = 0; i < length; i++)
{
if (numNonAlphanumericCharsAdded < numberOfNonAlphanumericCharacters && i < length - 1)
{
chars[i] = nonAlphanumericChars[random.Next(nonAlphanumericCharCount)];
numNonAlphanumericCharsAdded++;
}
else
{
chars[i] = allowedChars[random.Next(allowedCharCount)];
}
}
return new string(chars);
}
}

On my website I use this method:
//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();
}
Edit string _SymbolsAll for your array list.

Added some supplemental code to the accepted answer. It improves upon answers just using Random and allows for some password options. I also liked some of the options from the KeePass answer but did not want to include the executable in my solution.
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;
}
This was the first link when I searched for generating random passwords and the following is out of scope for the current question but might be important to consider.
Based upon the assumption that System.Web.Security.Membership.GeneratePassword is cryptographically secure with a minimum of 20% of the characters being Non-Alphanumeric.
Not sure if removing characters and appending strings is considered good practice in this case and provides enough entropy.
Might want to consider implementing in some way with SecureString for secure password storage in memory.

validChars can be any construct, but I decided to select based on ascii code ranges removing control chars. In this example, it is a 12 character string.
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)]; }))

This is short and it works great for me.
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();
}

Here Is what i put together quickly.
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;
}

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();
}

I use this code for generate password with balance composition of alphabet, numeric and non_alpha_numeric chars.
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;
}

Insert a Timer: timer1, 2 buttons: button1, button2, 1 textBox: textBox1, and a comboBox: comboBox1. Make sure you declare:
int count = 0;
Source Code:
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;
}
}