try {
         PackageInfo info = getPackageManager().getPackageInfo(
                 "my package name", 
                 PackageManager.GET_SIGNATURES);
         for (android.content.pm.Signature signature : info.signatures) {
             MessageDigest md = MessageDigest.getInstance("SHA");
             md.update(signature.toByteArray());
             Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
             }
     } catch (NameNotFoundException e) {

     } catch (NoSuchAlgorithmException e) {

     }

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