title: How do I migrate to hashed Firebase passwords?
body: <p>I have an existing client, which calls a server, which in turn calls</p>
  <pre><code>https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword
  </code></pre>
  <p>With that, client POSTs to the server (and server, to Firebase) an unhashed password over HTTPS.</p>
  <p>I would like to salt/hash the password on the client. I am at liberty to use the same algorithm Firebase uses. But I don't see a method for sending a hashed password to Firebase. And I have existing users who, of course, can't lose access with this migration.</p>