title: Apple Pay - decrypt payment data
body: <p>I am trying to decrypt <code>paymentData</code> property of <code>PKPaymentToken</code> object upon a successful Apple Pay authorization.</p>
  
  <p>I am trying to follow the instruction <a href="https://developer.apple.com/library/ios/documentation/PassKit/Reference/PaymentTokenJSON/PaymentTokenJSON.html" rel="nofollow">here</a>, but I am stuck on step 2 of the decryption steps, which says: </p>
  
  <blockquote>
    <p>Use the value of the publicKeyHash key to determine which merchant
    public key was used by Apple, and then retrieve the corresponding
    merchant public key certificate and private key.</p>
  </blockquote>
  
  <p>How do I do that?</p>
  
  <p>Please advise.</p>
  
  <p>Thanks!</p>