Researchers at the University of Michigan claim they have a processor that can't be hacked.
The description is a bit thin, but it seems a variation on memory shuffling to avoid direct attacks on specific locations.
I very much doubt that it is hack proof. (I'd go for "denial of service" first off ...)
Unhackable? Not a chance.
If it's unplugged and never used, then I will concede it's unhackable.
The term "unhackable" is two frequently banded around by those looking to further sales or uptake of services they offer. Yet-to-be-hacked, now that's a term I'm happy with.
Unhackable technology is up there with the discovery and keeping of unicorns or, simply put, non-existent.