title: Encrypt and decrypt data for Android app-client
body: <p>With this <a href="https://stackoverflow.com/questions/4830711/how-to-convert-a-image-into-base64-string?answertab=oldest#tab-top">way</a>
  I convert an image into a String.
  Now I want to encrypt this string before send the data in server. Is there a simple way to encrypt and decrypt the string?</p>