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AuthenticationManager Class

Manages the authentication modules called during the client authentication process.

System.Object
  System.Net.AuthenticationManager

Namespace:  System.Net
Assembly:  System (in System.dll)

public class AuthenticationManager

The AuthenticationManager type exposes the following members.

  NameDescription
Public propertyStatic memberCredentialPolicyGets or sets the credential policy to be used for resource requests made using the HttpWebRequest class.
Public propertyStatic memberCustomTargetNameDictionaryGets the dictionary that contains Service Principal Names (SPNs) that are used to identify hosts during Kerberos authentication for requests made using WebRequest and its derived classes.
Public propertyStatic memberRegisteredModulesGets a list of authentication modules that are registered with the authentication manager.
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  NameDescription
Public methodStatic memberAuthenticateCalls each registered authentication module to find the first module that can respond to the authentication request.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodStatic memberPreAuthenticatePreauthenticates a request.
Public methodStatic memberRegisterRegisters an authentication module with the authentication manager.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodStatic memberUnregister(IAuthenticationModule)Removes the specified authentication module from the list of registered modules.
Public methodStatic memberUnregister(String)Removes authentication modules with the specified authentication scheme from the list of registered modules.
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AuthenticationManager is a static class that manages the authentication modules that an application uses. When a request is made to protected resources, the AuthenticationManager calls the Authenticate method to get an Authorization instance to use in subsequent requests.

The AuthenticationManager queries each registered authentication module by calling the IAuthenticationModule.Authenticate method for each module. The first authentication module to return an Authorization instance is used to authenticate the request.

Modules that provide the basic, digest, negotiate, NTLM, and Kerberos authentication types are registered with the AuthenticationManager by default. Additional authentication modules that implement the IAuthenticationModule interface can be added using the Register method. Authentication modules are called in the order in which they were added to the list.

NoteNote

The Kerberos and negotiate authentication type is not supported on Windows 95/98 or Windows NT 4.0.



// The following example shows how to create a custom Basic authentication module,
// how to register it using the AuthenticationManager class and how to authorize  
// users to access a Web site.
// Note: To run this program you must create a test Web site that performs
// Basic authentication. Also you must add to your server machine a user whose
// credentials are the same as the ones you use in this program.
// Attention: Basic authentication sends the user's credentials over HTTP. 
// Passwords and user names are encoded using Base64 encoding. Although the 
// user information is encoded, it is considered insecure becasue it could be deciphered 
// relatively easily. 
// If you must use Basic authentication you are strongly advised to use strong 
// security mechanisms, such as SSL, when transferring sensitive information.


using System;
using System.Net;
using System.IO;
using System.Text;
using System.Collections;


namespace Mssc.Services.Authentication
{
  // The ClientAuthentication class performs the following main tasks:
  // 1) Obtains the user's credentials.
  // 2) Unregisters the standard Basic authentication.
  // 3) Registers the custom Basic authentication.
  // 4) Reads the selected page and displays it on the console.
  class TestAuthentication 
  {

    private static string username, password, domain, uri;

    // This method invoked when the user does not enter the required input parameters.
    private static void showusage() 
    {
      Console.WriteLine("Attempts to authenticate to a URL");
      Console.WriteLine("\r\nUse one of the following:");
      Console.WriteLine("\tcustomBasicAuthentication URL username password domain");
      Console.WriteLine("\tcustomBasicAuthentication URL username password");
    }

    // Display registered authentication modules.
    private static void displayRegisteredModules() 
    {
      // The AuthenticationManager calls all authentication modules sequentially 
      // until one of them responds with an authorization instance.  Show
      // the current registered modules.
      IEnumerator registeredModules = AuthenticationManager.RegisteredModules; 
      Console.WriteLine("\r\nThe following authentication modules are now registered with the system:");
      while(registeredModules.MoveNext())
      {
        Console.WriteLine("\r \n Module : {0}",registeredModules.Current); 
        IAuthenticationModule currentAuthenticationModule = (IAuthenticationModule)registeredModules.Current;
        Console.WriteLine("\t  CanPreAuthenticate : {0}",currentAuthenticationModule.CanPreAuthenticate); 
      }      
    }

    // The getPage method accesses the selected page and displays its content 
    // on the console.
    private static void getPage(String url) 
    {
      try 
      {
        // Create the Web request object.
        HttpWebRequest req = (HttpWebRequest) WebRequest.Create(url);

        // Define the request access method.
        req.Method = "GET";

        // Define the request credentials according to the user's input.
        if (domain == String.Empty)
          req.Credentials = new NetworkCredential(username, password);
        else
          // If the user does not specify the Internet resource domain, this usually
          // is by default the name of the sever hosting the resource.
          req.Credentials = new NetworkCredential(username, password, domain);

        // Issue the request.
        HttpWebResponse result = (HttpWebResponse) req.GetResponse();

        Console.WriteLine("\nAuthentication Succeeded:");

        // Store the response.
        Stream sData = result.GetResponseStream();

        // Display the response.
        displayPageContent(sData);
      }
      catch (WebException e)
      {
        // Display any errors. In particular, display any protocol-related error. 
        if (e.Status == WebExceptionStatus.ProtocolError)
        {                
          HttpWebResponse hresp = (HttpWebResponse) e.Response;
          Console.WriteLine("\nAuthentication Failed, " + hresp.StatusCode);
          Console.WriteLine("Status Code: " + (int) hresp.StatusCode);
          Console.WriteLine("Status Description: " + hresp.StatusDescription);                
          return;
        }
        Console.WriteLine("Caught Exception: " + e.Message);
        Console.WriteLine("Stack: " + e.StackTrace);
      }
    }

    // The displayPageContent method display the content of the
    // selected page.
    private static void displayPageContent(Stream ReceiveStream) 
    {
      // Create an ASCII encoding object.
      Encoding ASCII = Encoding.ASCII;

      // Define the byte array to temporarily hold the current read bytes. 
      Byte[] read = new Byte[512];

      Console.WriteLine("\r\nPage Content...\r\n");

      // Read the page content and display it on the console.
      // Read the first 512 bytes.
      int bytes = ReceiveStream.Read(read, 0, 512);
      while (bytes > 0) 
      {
        Console.Write(ASCII.GetString(read, 0, bytes));
        bytes = ReceiveStream.Read(read, 0, 512);
      }
      Console.WriteLine("");
    }

    // This is the program entry point. It allows the user to enter 
    // her credentials and the Internet resource (Web page) to access.
    // It also unregisters the standard and registers the customized Basic 
    // authentication.
    public static void Main(string[] args) 
    {

      if (args.Length < 3)
        showusage();
      else 
      {    

        // Read the user's credentials.
        uri = args[0];
        username = args[1];
        password = args[2];

        if (args.Length == 3)
          domain = string.Empty;
        else
          // If the domain exists, store it. Usually the domain name
          // is by default the name of the server hosting the Internet
          // resource.
          domain = args[3];


        // Instantiate the custom Basic authentication module.
        CustomBasic customBasicModule = new CustomBasic();

        // Unregister the standard Basic authentication module.
        AuthenticationManager.Unregister("Basic");

        // Register the custom Basic authentication module.
        AuthenticationManager.Register(customBasicModule);

        // Display registered authorization modules.
        displayRegisteredModules();

        // Read the specified page and display it on the console.
        getPage(uri);
      }
      return;
    }
  }

  // The CustomBasic class creates a custom Basic authentication by implementing the
  // IAuthenticationModule interface. It performs the following
  // tasks:
  // 1) Defines and initializes the required properties.
  // 2) Implements the Authenticate method.

  public class CustomBasic : IAuthenticationModule
  {

    private string m_authenticationType ;
    private bool m_canPreAuthenticate ;

    // The CustomBasic constructor initializes the properties of the customized 
    // authentication.
    public CustomBasic()
    {
      m_authenticationType = "Basic";
      m_canPreAuthenticate = false;
    }

    // Define the authentication type. This type is then used to identify this
    // custom authentication module. The default is set to Basic.
    public string AuthenticationType
    {
      get
      {
        return m_authenticationType;
      }
    }

    // Define the pre-authentication capabilities for the module. The default is set
    // to false.
    public bool CanPreAuthenticate
    {
      get
      {
        return m_canPreAuthenticate;
      }
    }

    // The checkChallenge method checks whether the challenge sent by the HttpWebRequest 
    // contains the correct type (Basic) and the correct domain name. 
    // Note: The challenge is in the form BASIC REALM="DOMAINNAME"; 
    // the Internet Web site must reside on a server whose
    // domain name is equal to DOMAINNAME.
    public bool checkChallenge(string Challenge, string domain) 
    {
      bool challengePasses = false;

      String tempChallenge = Challenge.ToUpper();

      // Verify that this is a Basic authorization request and that the requested domain
      // is correct.
      // Note: When the domain is an empty string, the following code only checks 
      // whether the authorization type is Basic.

      if (tempChallenge.IndexOf("BASIC") != -1)
        if (domain != String.Empty)
          if (tempChallenge.IndexOf(domain.ToUpper()) != -1)
            challengePasses = true;
          else
            // The domain is not allowed and the authorization type is Basic.
            challengePasses = false;
        else
          // The domain is a blank string and the authorization type is Basic.
          challengePasses = true;

      return challengePasses;
    }

    // The PreAuthenticate method specifies whether the authentication implemented 
    // by this class allows pre-authentication. 
    // Even if you do not use it, this method must be implemented to obey to the rules 
    // of interface implementation.
    // In this case it always returns null. 
    public Authorization PreAuthenticate(WebRequest request, ICredentials credentials) 
    {                
      return null;
    }

    // Authenticate is the core method for this custom authentication.
    // When an Internet resource requests authentication, the WebRequest.GetResponse 
    // method calls the AuthenticationManager.Authenticate method. This method, in 
    // turn, calls the Authenticate method on each of the registered authentication
    // modules, in the order in which they were registered. When the authentication is 
    // complete an Authorization object is returned to the WebRequest.
    public Authorization Authenticate(String challenge, WebRequest request, ICredentials credentials) 
    {
      Encoding ASCII = Encoding.ASCII;        

      // Get the username and password from the credentials
      NetworkCredential MyCreds = credentials.GetCredential(request.RequestUri, "Basic");        

      if (PreAuthenticate(request, credentials) == null)
        Console.WriteLine("\n Pre-authentication is not allowed.");
      else
        Console.WriteLine("\n Pre-authentication is allowed.");

      // Verify that the challenge satisfies the authorization requirements.
      bool challengeOk = checkChallenge(challenge, MyCreds.Domain);

      if (!challengeOk)
        return null;

      // Create the encrypted string according to the Basic authentication format as
      // follows:
      // a)Concatenate the username and password separated by colon;
      // b)Apply ASCII encoding to obtain a stream of bytes;
      // c)Apply Base64 encoding to this array of bytes to obtain the encoded 
      // authorization.
      string BasicEncrypt = MyCreds.UserName + ":" + MyCreds.Password;

      string BasicToken = "Basic " + Convert.ToBase64String(ASCII.GetBytes(BasicEncrypt));

      // Create an Authorization object using the encoded authorization above.
      Authorization resourceAuthorization = new Authorization(BasicToken);

      // Get the Message property, which contains the authorization string that the 
      // client returns to the server when accessing protected resources.
      Console.WriteLine("\n Authorization Message:{0}",resourceAuthorization.Message);

      // Get the Complete property, which is set to true when the authentication process 
      // between the client and the server is finished.
      Console.WriteLine("\n Authorization Complete:{0}",resourceAuthorization.Complete);

      Console.WriteLine("\n Authorization ConnectionGroupId:{0}",resourceAuthorization.ConnectionGroupId);


      return resourceAuthorization;
    }
  }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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