I would like to implement an anti-counterfeiting scheme for tools my company manufactures. This would ideally be done via RFID/NFC tags. However, the environment in which these tags operate would either be behind a heavy firewall or not web-enabled at all. So a database of unique, valid numbers isn't feasible. I'd rather have some sort of generic key programmed to the tag that the software could then verify. However, since all the tags will contain common data, this presents the possibility that a tag could be cloned since the data (or at least a portion of it) on the tag will be identical.
In other words, I am not interested in protecting the contents of the secret message. Rather, I am concerned about ensuring that the tags cannot be cloned and then embedded on other, counterfeit tools.
While AES-128 is high security, I am questioning whether or not this encryption method is cloneable. If so, what other encryption technologies might I want to look into? I've been looking into the Algebraic Eraser and SecureRF, which use a public-key methodology.