title: Is there a two-way hashing algorithm in PHP?
body: <blockquote>
    <p><strong>Disclaimer:</strong> I understand that a hash is not <em>supposed</em> to be reversible. </p>
  </blockquote>
  
  <p>I've seen many people ask if there is a way to "unhash" text that is already hashed.  However, I am not seeing a straight answer.  Most answers state that MD5 and SHA-1 are one-way hashing algorthims, and therefore irreversible.  That's great and all, but it begs the question are <strong>all</strong> hashing algorithms one-way and irreversible?</p>