title: How to decrypt a Rails 5 session cookie manually?
body: <p>I have access to</p>
  
  <ul>
  <li><code>config.action_dispatch.encrypted_cookie_salt</code></li>
  <li><code>config.action_dispatch.encrypted_signed_cookie_salt</code></li>
  <li><code>secrets.secret_key_base</code></li>
  <li>the full cookie string (including <code>--</code>)</li>
  </ul>
  
  <p>I see ways to do this in Rails 4 (<a href="https://stackoverflow.com/questions/35013568/rails-4-how-to-decrypt-rails-4-session-cookie-given-the-session-key-and-secret">Rails 4: How to decrypt rails 4 session cookie (Given the session key and secret)</a>), but these don't seem to work in Rails 5.</p>