Bcrypt, what is meant salt and cost? <p>I was always using MD5 for encrypting passwords, but I read that it's should no more be used, and instead use bcrypt.. </p> <p>I'm using zendframework 2 , where I found it describing bcrypt configurations as follows:</p> <pre><code>$bcrypt = new Bcrypt(array( 'salt' =&gt; 'random value', 'cost' =&gt; 11 )); </code></pre> <p>what is the salt and what is the cost ? and how could them be used?</p>