Could hacktivists attack the Interactive Democracy system? Could foreign governments attack it? We are, perhaps, seeing the emergence of cyber wars, cyber terrorism, cyber vandalism, cyber coercion.
The main threat to ID wouldn't be the obvious attacks, we can just press the re-set button and vote again, it would be the unnoticed corruption.
Apart from a wide range of technical defences, each individual should monitor their own ID account, much like we monitor our bank accounts, looking for spurious transactions.