For adding the reference of the Microsoft.SharePoint.IdentityModel dll, navigate to the c:\Windows\Assembly\GAC_MSIL folder.
Select the folder “Microsoft. SharePoint.IdentityModel”
once the folder is opened, you will find a version and guid mapped folder,
once you open the folder, you will see the dll from which you need to add a reference to your application.
<%@ Assembly Name=”Microsoft.SharePoint.IdentityModel, Version=18.104.22.168, Culture=neutral, PublicKeyToken=71e9bce111e9429c” %>
<asp:Login ID=”signInControl” FailureText=”<%$Resources:wss,login_FailureText%>”
runat=”server” Width=”100%” DisplayRememberMe=”false” />
Custom Login Logic
If you want to add the Custom Login logic into your control, like, you need to perform some additional activities like sending mails to the user, generating notification alerts for the user, then you will need to place your custom logic in the code behind pages.
Once all this has been performed, the development of the login page is complete and we need to configure the Login page in the central administration.