title: Customize the cookie value in MVC5 ASP.NET Identity
body: <p>I am in the process of changing our authentication implementation to use MVC5 ASP.NET Identity with Owin.</p>
  
  <p>However we need to integrate our sign in with other linked applications and websites on the same domain. We currently do this by sharing the cookie between applications across a number of subdomains. The cookie in a very specific format and encryption algorithm that a variety of applications and technologies (ie not all are in .NET or on the same server) can use.</p>
  
  <p>I have found that in the App_Start ConfigureAuth.cs you can set the app.UseCookieAuthentication to specify things like the cookie name and the subdomain of the cookie (eg <a href="https://stackoverflow.com/questions/19166599/asp-net-identity-cookie-across-subdomains">ASP.NET Identity Cookie across subdomains</a>). </p>
  
  <p>This is a very good start, but I also need to change the actual value of the cookie to be a specific format and encryption algorithm.</p>
  
  <p>Does anyone know how to customize the value and encryption type used to create and read the cookie?</p>
  
  <p>Thanks for any help,
  Saan</p>