Those testing the first beta of iOS 7 and trying to use a third-party Lightning cable for charging their devices are reportedly being surprised with a new warning message that says:
This cable or accessory is not certified and may not work reliably with this iPhone.
For those that have managed to create clones, Apple’s devices on iOS 7 appear to be able to tell when the cables aren’t legitimately from Apple. As noted by MacRumors, iOS 7 doesn't prevent the third-party Lightning cables from functioning properly, however. They will still charge and sync the device as expected.