title: Crypting data with a X509 certificate in PHP
body: <p>I need to send crypted data to a payment site and their instructions tells me this:</p>
  
  <blockquote>
    <p>-X509 public certificate : "This site" will generate a X509 public certificate
    for every merchant account created. You’ll have to use this certificate in order
    to encrypt data every time you initiate to "this site" a
     payment. This cannot be
    used to decrypt data, "this site" will use a private key to decrypt. </p>
  </blockquote>
  
  <p>From what I know and what I saw in PHP documentations, you can only check with certificate if data is signed. So how could I encrypt data with this certificate given and do what they want?</p>