title: Membership can't validate user after providing machineKey
body: <p>I have a web site with two endpoints, let's say <strong>www.mydomain.com</strong> and <strong>mydomain.com</strong>.</p>
  
  <p>I need my user stay loged in when he jumps from one domain to another.</p>
  
  <p>For this task I could force my users to login on one of domain (let's call it the main) and if somebody visits another - just redirect him to the main domain.</p>
  
  <p>But I have read that I can use <a href="http://msdn.microsoft.com/en-us/library/eb0zx8fc.aspx" rel="nofollow">Forms Authentication Across Applications</a> and share the same authentication ticket accross multiple domains.</p>
  
  <p>So I decided to give a try to this approach, but it doesn't work for me... the main question why?</p>
  
  <p>What I did:</p>
  
  <ol>
  <li>I generated new machineKey from this <a href="http://aspnetresources.com/tools/machineKey" rel="nofollow">service</a>. </li>
  <li>Added it in my <code>web.config</code>.</li>
  </ol>
  
  <p>After this step my old membership provider stoped working correctly. It doesn't validate users with right passwords.</p>
  
  <p>I suppose it's because all passwords in my current database should be encrypted by values from <a href="http://msdn.microsoft.com/en-us/library/ff649308.aspx#paght000007_webfarmdeploymentconsiderations" rel="nofollow">machineKey</a> section.</p>
  
  <p>Could anybody point me at what I am doing wrong and is it possible to make shared authentication with machineKeys and existing membership database that contains passwords in hashed format?</p>
  
  <p>I also experimented with addint <code>protection="All"</code> (I assume that it shouldn't work with hashed password because it forces its encryption by machineKeys) and <code>domain="mydomain.com"</code> attributes to my <code>&lt;forms/&gt;</code> section in <code>web.config</code>, but - no luck.</p>