title: DecryptMessage returning SEC_E_UNSUPPORTED_FUNCTION
body: <p>I have compiled libstrophe as a DLL for Windows.   </p>
  
  <p>During authorisation with the Jabber server <code>DecryptMessage()</code> is called three times as stanzas are passed back and forth. On the first two calls it returns <code>0 (SEC_E_OK)</code>, but on the third call it returns <code>0x80090302 (SEC_E_UNSUPPORTED_FUNCTION)</code>. The <strong>problem</strong> is, according to the <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa375348%28v=vs.85%29.aspx" rel="nofollow">documentation</a> <code>SEC_E_UNSUPPORTED_FUNCTION</code> is not a valid return value. This happens both on Windows 7 and Windows XP.</p>
  
  <p>I tried replacing the incoming encrypted string with garbage to see what was the return value, and it was <code>0x80090318 (SEC_E_INCOMPLETE_MESSAGE)</code>, so I know it's not simply a case of "garbage in - garbage out". I've also checked the JID is correct by logging in with the same JID using Pidgin.</p>
  
  <p>Can anyone offer any enlightenment please?</p>