title: Testing if string is sha1 in PHP
body: <p>I'm planning on storing the passwords as a sha1, so I need a way to validate that it is a sha1 at another point in my website. I was planning on using preg_match, but I do not know how to make regex patterns. Could someone help me out with one?</p>
  
  <p>Thanks</p>
  
  <p>Edit: I am not trying to see if two hashes match.</p>