title: What are the differences between .pem, .cer and .der?
body: <p>What are the differences between <code>.pem</code>, <code>.cer</code> and <code>.der</code>?</p>
  
  <p>As far as I know, <code>.cer</code> contains public key. Are there any open frameworks that I can use to encrypt my data using this public key?</p>