Csharp/CSharp Tutorial/Security/WindowsIdentity

Determining group identity: WindowsBuiltInRole.PowerUser

<source lang="csharp">using System; using System.Security.Principal; class MainClass {

 public static void Main() 
 {
   WindowsIdentity wi = WindowsIdentity.GetCurrent();
   WindowsPrincipal prin = new WindowsPrincipal(wi);
   if (prin.IsInRole(WindowsBuiltInRole.PowerUser)) 
   {
     Console.WriteLine("You are a member of the Power User group");
   }
   else
   {
     Console.WriteLine("You are not a member of the Power User group");
   }
 }

}</source>

You are not a member of the Power User group

Get current principal identity name

<source lang="csharp">using System; using System.Threading; using System.Security; using System.Security.Permissions; using System.Collections.Generic; using System.Text; using System.Collections;

   class Program
   {
       static void Main(string[] args)
       {          
           System.Security.Principal.WindowsIdentity wi = System.Security.Principal.WindowsIdentity.GetCurrent();
           Thread.CurrentPrincipal = new System.Security.Principal.WindowsPrincipal(wi);
           Console.WriteLine(wi.Name);
           Console.WriteLine(Thread.CurrentPrincipal.Identity.Name);
           PrincipalPermission pp = new PrincipalPermission(null, "Administrators", true);
           pp.Demand();
           PrincipalPermission pp2 = new PrincipalPermission(null, "Users", true);
           pp.Union(pp2).Demand();
           try
           {
               PrincipalPermission pp3 = new PrincipalPermission(null, "Club");
               pp3.Demand();
           }
           catch (SecurityException e)
           {
               Console.WriteLine("You do not have access to the secret club.");
           }
       }
   }</source>

Get the current identity

<source lang="csharp">using System; using System.Security.Principal;

class MainClass {

 public static void Main() 
 {
   WindowsIdentity wi = WindowsIdentity.GetCurrent();
   Console.WriteLine("Identity information:");
   Console.WriteLine("  Authentication Type: {0}",wi.AuthenticationType);
   Console.WriteLine("  Is Anonymous: {0}", wi.IsAnonymous);
   Console.WriteLine("  Is Authenticated: {0}", wi.IsAuthenticated);
   Console.WriteLine("  Is Guest: {0}", wi.IsGuest);
   Console.WriteLine("  Is System: {0}", wi.IsSystem);
   Console.WriteLine("  Name: {0}", wi.Name);
   Console.WriteLine("  Token: {0}", wi.Token);
 }

}</source>

Identity information:
  Authentication Type: NTLM
  Is Anonymous: False
  Is Authenticated: True
  Is Guest: False
  Is System: False
  Name: nfex\Joe
  Token: 1800

Get the current identity and its associated principal

<source lang="csharp">using System; using System.Security.Principal;

class MainClass {

 public static void Main() 
 {
   WindowsIdentity wi = WindowsIdentity.GetCurrent();
   
   WindowsPrincipal prin = new WindowsPrincipal(wi);
   Console.WriteLine("Principal information:");
   Console.WriteLine("  Authentication Type: {0}", prin.Identity.AuthenticationType);
   Console.WriteLine("  Is authenticated: {0}", prin.Identity.IsAuthenticated);
   Console.WriteLine("  Name: {0}", prin.Identity.Name);
 }

}</source>

Principal information:
  Authentication Type: NTLM
  Is authenticated: True
  Name: nfex\Joe

Impersonation

<source lang="csharp">using System; using System.Collections.Generic; using System.IO; using System.IO.IsolatedStorage; using System.Net; using System.Net.Sockets; using System.Reflection; using System.Security; using System.Security.AccessControl; using System.Security.Policy; using System.Security.Permissions; using System.Security.Principal; using System.Text; public class MainClass {

   public static void Main()
   {
       WindowsIdentity identity = WindowsIdentity.GetCurrent();
       WindowsImpersonationContext context = identity.Impersonate();
       context.Undo();
   }

}</source>

Iterate through the group names to see if the current user is a member of each one

<source lang="csharp">using System; using System.Security.Principal; class MainClass {

   public static void Main (string[] args) 
   {
       
       WindowsIdentity identity = WindowsIdentity.GetCurrent();
       WindowsPrincipal principal = new WindowsPrincipal(identity);
       
       foreach (string role in args) 
       {
           Console.WriteLine("Is {0} a member of {1}? = {2}", identity.Name, role, principal.IsInRole(role));
       }
   }

}</source>

Obtain a WindowsIdentity object representing the currently logged on Windows user

<source lang="csharp">using System; using System.Security.Principal; class MainClass {

   public static void Main (string[] args) 
   {
       
       WindowsIdentity identity = WindowsIdentity.GetCurrent();
   }

}</source>