title: How to create signed apk using upload_cert.der file
body: <p>I have read many reference about Google app signing but still did not found my requirement. I have only <code>upload_cert.der</code> and <code>deployment_cert.der</code> file. I have not access of publisher play store account. I have to only created updated APK and deliver its to client and client will upload it. Now my question is that :</p>
  
  <ul>
  <li>If i have only <code>upload_cert.der</code> and <code>deployment_cert.der</code> file then, can we create signed apk which can update existing application on store?</li>
  <li>If above requirement is possible then please explain step by step process of creating signed apk using <code>upload_cert.der</code> and <code>deployment_cert.der</code> file that can successfully update exiting application.</li>
  </ul>