This is almost exactly how I tried it initially - except that I don't die with an error message; I just skip the file. It is how common sense suggests that the package should behave. But it DOES NOT! Try passing it a text file instead of a ZIP archive and you'll see. It will spew half a screen of error messages (basically complaining about the lack of signature and going downhill from there), instead of keeping silent and simply returning some error code that is not AZ_OK.