title: Open source replacement for sun.security.rsa.RSAPublicKeyImpl
body: <p>I get some warnings due to use of RSAPublicKeyImpl:</p>
  
  <blockquote>
    <p>warning: RSAPublicKeyImpl is internal proprietary API and may be
    removed in a future release import sun.security.rsa.RSAPublicKeyImpl;</p>
  </blockquote>
  
  <p>I have tried to find a replacement, but with no luck. What is the open source alternative for this class?</p>