title: How to measure hash algorithm strength
body: <p>Is there a way to measure the strength of hash algorithms? For instance, a standardised test, written in PHP, to measure the strength of, perhaps, <code>crypt</code> vs. <code>sha1</code>? </p>
  
  <p>Strength can refer to various things; the ability a single home computer can discover the password through a rainbow table or a character loop, the length of bits in the password or the use of symbols and numbers. Unlike simple regular expressions which discover symbols or the number of characters, a requirement for the PHP function which can determine strength, is from how fast the password, key or salt can be broken. </p>
  
  <p>I would like to know, without opinion, which hashing algorithm is best from a PHP's list of hashing algorithms.</p>
  
  <pre><code>foreach (hash_algos() as $algorithm) {
      // test strength
  }
  </code></pre>