title: Refresh and ValidityCheck operations in the SEAL Code
body: <p>While reading the <a href="https://projects.csail.mit.edu/HEWorkshop/HomomorphicEncryptionStandard2018.pdf" rel="nofollow noreferrer">Homomorphic Encryption Standard</a> I came across those two operations:</p>
  
  <ol>
  <li>Refresh(Params, flag, EK, C1) → C2.</li>
  <li>ValidityCheck(Params, EK, [C], COMP) → flag.</li>
  </ol>
  
  <p>I've searched their implementation in the SEAL Code but couldn’t find any, although I think that the first one is only implemented as <code>evaluator.relinearize()</code>.</p>