title: Encoding cookies so they cannot be spoofed or read etc
body: <p>I am writing a PHP application.  I want to store user login information in cookies so user's dont have to log in on every visit.</p>
  
  <p>I want to encode them or obfuscate them so that they cannot be read or tampered with.</p>
  
  <p>What is the best way to do this?</p>
  
  <p>Update:</p>
  
  <p>I am not going to be storing passwords in the cookies, simply a user ID so that I know who they are, but I want this to be encoded or encrypted so no one can spoof other users</p>