title: Is my machine key auto-generated or isolated?
body: <p>I'm attempting to share <code>.ASPXAUTH</code> cookies between an ASP.NET MVC 4 application (in IIS 7.5) and a service using <code>HttpListener</code> on the same host.</p>
  
  <p>The browser presents the cookies to both correctly, but my service receives <code>System.Web.HttpException: Unable to validate data.</code> at <code>FormsAuthentication.Decrypt</code>, which I would expect if the two applications were using different machine keys.</p>
  
  <p>So: how do I find out if my machine is configured to use different machine keys?</p>