FormsAuthentication.HashPasswordForStoringInConfigFile Method (System.Web.Security)

.NET Framework Class Library

FormsAuthentication..::.HashPasswordForStoringInConfigFile Method

Produces a hash password suitable for storing in a configuration file based on the specified password and hash algorithm.

Namespace: System.Web.Security
Assembly: System.Web (in System.Web.dll)

Syntax

Visual Basic (Declaration)

Public Shared Function HashPasswordForStoringInConfigFile ( _
    password As String, _
    passwordFormat As String _
) As String

Visual Basic (Usage)

Dim password As String
Dim passwordFormat As String
Dim returnValue As String

returnValue = FormsAuthentication.HashPasswordForStoringInConfigFile(password, _
    passwordFormat)

public static string HashPasswordForStoringInConfigFile(
    string password,
    string passwordFormat
)

Visual C++

public:
static String^ HashPasswordForStoringInConfigFile(
    String^ password, 
    String^ passwordFormat
)

JScript

public static function HashPasswordForStoringInConfigFile(
    password : String, 
    passwordFormat : String
) : String

Parameters

password: Type: System..::.String
The password to hash.

passwordFormat: Type: System..::.String
The hash algorithm to use. passwordFormat is a String that represents one of the FormsAuthPasswordFormat enumeration values.

Return Value

Type: System..::.String
The hashed password.

Exceptions

Exception	Condition
ArgumentNullException	password is nullNothingnullptra null reference (Nothing in Visual Basic) -or- passwordFormat is nullNothingnullptra null reference (Nothing in Visual Basic).
ArgumentException	passwordFormat is not a valid FormsAuthPasswordFormat value.

Exception

Condition

ArgumentNullException

password is nullNothingnullptra null reference (Nothing in Visual Basic)

-or-

passwordFormat is nullNothingnullptra null reference (Nothing in Visual Basic).

ArgumentException

passwordFormat is not a valid FormsAuthPasswordFormat value.

Remarks

The HashPasswordForStoringInConfigFile method creates a hashed password value that can be used when storing forms-authentication credentials in the configuration file for an application.

Authentication credentials stored in the configuration file for an application are used by the Authenticate method to verify passwords for users of an application. Alternatively, you can use ASP.NET membership to store user credentials. For more information, see Managing Users by Using Membership.

Examples

The following code example takes a user name, password, and hash type and displays the credentials section of the configuration that includes the user definition and hashed password.

Security Note:
This example contains a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

Visual Basic

<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
   <head>
    <title>ASP.NET Example</title>
<script runat="server">
         Sub Cancel_Click(sender As Object, e As EventArgs)
            userName.Text = ""
            password.Text = ""
            repeatPassword.Text = ""
            result.Text = ""
         End Sub

         Sub HashPassword_Click(sender As Object, e As EventArgs)
            If Page.IsValid Then
               Dim hashMethod As String = ""

               If md5.Checked Then
                  hashMethod = "MD5"
               Else
                  hashMethod = "SHA1"
               End If

               Dim hashedPassword As String = _
                  FormsAuthentication.HashPasswordForStoringInConfigFile(password.Text, hashMethod)

               result.Text = "&lt;credentials passwordFormat=""" & hashMethod & _
                 """&gt;<br />" & "  &lt;user name=""" & Server.HtmlEncode(userName.Text) & """ password=""" & _
                 hashedPassword & """ /&gt;<br />" & "&lt;/credentials&gt;"
            Else
               result.Text = "There was an error on the page."
            End If
         End Sub
      </script>
   </head>

   <body>
      <form id="form1" runat="server">
         <p>This form displays the results of the FormsAuthentication.HashPasswordForStoringInConfigFile
         method.<br />The user name and hashed password can be stored in a &lt;credentials&gt; node
         in the Web.config file.</p>
         <table cellpadding="2">
            <tbody>
               <tr>
                  <td>New User Name:</td>
                  <td><asp:TextBox id="userName" runat="server" /></td>
                  <td><asp:RequiredFieldValidator id="userNameRequiredValidator" 
                        runat="server" ErrorMessage="User name required" 
                        ControlToValidate="userName" /></td>
               </tr>
               <tr>
                  <td>Password: </td>
                  <td><asp:TextBox id="password" runat="server" TextMode="Password" /></td>
                  <td><asp:RequiredFieldValidator id="passwordRequiredValidator" 
                        runat="server" ErrorMessage="Password required" 
                        ControlToValidate="password" /></td>
               </tr>
               <tr>
                  <td>Repeat Password: </td>
                  <td><asp:TextBox id="repeatPassword" runat="server" TextMode="Password" /></td>
                  <td><asp:RequiredFieldValidator id="repeatPasswordRequiredValidator" 
                        runat="server" ErrorMessage="Password confirmation required" 
                        ControlToValidate="repeatPassword" />
                      <asp:CompareValidator id="passwordCompareValidator" runat="server" 
                        ErrorMessage="Password does not match" 
                        ControlToValidate="repeatPassword" 
                        ControlToCompare="password" /></td>
               </tr>
               <tr>
                  <td>Hash function:</td>
                  <td align="center">
                     <asp:RadioButton id="sha1" runat="server" GroupName="HashType" 
                                      Text="SHA1" />
                     <asp:RadioButton id="md5" runat="server" GroupName="HashType" 
                                      Text="MD5" />
                  </td>
               </tr>
               <tr>
                  <td align="center" colspan="2">
                    <asp:Button id="hashPassword" onclick="HashPassword_Click" 
                                runat="server" Text="Hash Password" />&nbsp;&nbsp; 
                    <asp:Button id="cancel" onclick="Cancel_Click" runat="server" 
                                Text="Cancel" CausesValidation="false" />
                  </td>
               </tr>
            </tbody>
         </table>

         <pre><asp:Label id="result" runat="server"></asp:Label></pre>
      </form>
   </body>
</html>

<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
   <head>
    <title>ASP.NET Example</title>
<script runat="server">
         void Cancel_Click(object sender, EventArgs e)
         {
            userName.Text = "";
            password.Text = "";
            repeatPassword.Text = "";
            result.Text = "";
         }

         void HashPassword_Click(object sender, EventArgs e)
         {
            if (Page.IsValid)
            {
               string hashMethod = "";

               if (md5.Checked)
               {
                  hashMethod = "MD5";
               }
               else
               {
                  hashMethod = "SHA1";
               }

               string hashedPassword =
                  FormsAuthentication.HashPasswordForStoringInConfigFile(password.Text, hashMethod);

               result.Text = "&lt;credentials passwordFormat=\"" + hashMethod +"\"&gt;<br />" +
                  "  &lt;user name=\"" + Server.HtmlEncode(userName.Text) + "\" password=\"" +
                  hashedPassword + "\" /&gt;<br />" + "&lt;/credentials&gt;";
            }
            else
            {
               result.Text = "There was an error on the page.";
            }
         }
      </script>
   </head>

   <body>
      <form id="form1" runat="server">
         <p>This form displays the results of the FormsAuthentication.HashPasswordForStoringInConfigFile
         method.<br />The user name and hashed password can be stored in a &lt;credentials&gt; node
         in the Web.config file.</p>
         <table cellpadding="2">
            <tbody>
               <tr>
                  <td>New User Name:</td>
                  <td><asp:TextBox id="userName" runat="server" /></td>
                  <td><asp:RequiredFieldValidator id="userNameRequiredValidator" 
                        runat="server" ErrorMessage="User name required" 
                        ControlToValidate="userName" /></td>
               </tr>
               <tr>
                  <td>Password: </td>
                  <td><asp:TextBox id="password" runat="server" TextMode="Password" /></td>
                  <td><asp:RequiredFieldValidator id="passwordRequiredValidator" 
                        runat="server" ErrorMessage="Password required" 
                        ControlToValidate="password" /></td>
               </tr>
               <tr>
                  <td>Repeat Password: </td>
                  <td><asp:TextBox id="repeatPassword" runat="server" TextMode="Password" /></td>
                  <td><asp:RequiredFieldValidator id="repeatPasswordRequiredValidator" 
                        runat="server" ErrorMessage="Password confirmation required" 
                        ControlToValidate="repeatPassword" />
                      <asp:CompareValidator id="passwordCompareValidator" runat="server" 
                        ErrorMessage="Password does not match" 
                        ControlToValidate="repeatPassword" 
                        ControlToCompare="password" /></td>
               </tr>
               <tr>
                  <td>Hash function:</td>
                  <td align="center">
                     <asp:RadioButton id="sha1" runat="server" GroupName="HashType" 
                                      Text="SHA1" />
                     <asp:RadioButton id="md5" runat="server" GroupName="HashType" 
                                      Text="MD5" />
                  </td>
               </tr>
               <tr>
                  <td align="center" colspan="2">
                    <asp:Button id="hashPassword" onclick="HashPassword_Click" 
                                runat="server" Text="Hash Password" />&nbsp;&nbsp; 
                    <asp:Button id="cancel" onclick="Cancel_Click" runat="server" 
                                Text="Cancel" CausesValidation="false" />
                  </td>
               </tr>
            </tbody>
         </table>

         <pre><asp:Label id="result" runat="server"></asp:Label></pre>
      </form>
   </body>
</html>

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

Version Information

.NET Framework

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

Reference

FormsAuthentication Class

FormsAuthentication Members

System.Web.Security Namespace

Other Resources

ASP.NET Web Application Security