Using RNGCryptoServiceProvider and Character Masking

Uniquekey Generate Method

Code :

using System.Security.Cryptography;

import the above class for using the code

private string GetUniqueKey()

  {

  int maxSize  = 8 ;

  int minSize = 5 ;

  char[] chars = new char[62];

  string a;

  a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";

  chars = a.ToCharArray();

  int size  = maxSize ;

  byte[] data = new byte[1];

  RNGCryptoServiceProvider  crypto = new RNGCryptoServiceProvider();

  crypto.GetNonZeroBytes(data) ;

  size =  maxSize ;

  data = new byte[size];

  crypto.GetNonZeroBytes(data);

  StringBuilder result = new StringBuilder(size) ;

  foreach(byte b in data )

{ result.Append(chars[b % (chars.Length - 1)]); }

   return result.ToString();

  }

Generation Method	Time Taken	Number of Generated Keys	Number of Duplicate Keys	All Fixed Length Keys
Using DateTime and HashCode	01.56 sec	10,00,000	500131	No
Using GUIDs and HashCode	04.45 sec	10,00,000	113	No
Using RNGCryptoServiceProvider and Character Masking	00.40 sec	10,00,000	0 (Wow!!)	Yes

Using DateTime and HashCode:

Using DateTime for generating unique keys is very common practice. I have remixed this approach by inducing HashCode in it also. Like

Code :

DateTime.Now.ToString().GetHashCode().ToString("x"); 

Using GUIDs and HashCode:

Code :
Guid.NewGuid().ToString().GetHashCode().ToString("x");