title: Regular expression for base 58 private key?
body: <p>I'm looking for a regex that will validate a base 58 bitcoin private key.  I found this one for public addresses:</p>
  
  <pre><code>/^[13n][1-9A-Za-z][^OIl]{20,40}/
  </code></pre>
  
  <p>But I don't know what the requirements are for a private key.</p>