title: What is the differences between `export signed` and `unsigned` .apk file?
body: <p>I'm building .apk file for my Android application using <code>Android tools - Export...</code> as guided <a href="https://stackoverflow.com/questions/7801491/how-do-you-compile-an-android-project-into-an-apk-file-in-eclipse-without-launc">here</a></p>
  
  <p>My question is what are signed and unsigned .apk file?</p>
  
  <p>How can we use usngined .apk file? (I tried to export an unsigned one but I cannot install it for my Galaxy Nexus)</p>
  
  <p><img src="https://i.stack.imgur.com/6Ek01.png" alt=""></p>