Schneier on Security

Clive Robinson • December 17, 2024 9:14 PM

@ Bruce, All,

With regards,

“The whole point of a license plate is that it can’t be modified. Why in the world would anyone thin[k] that a digital version is a good idea?”

That might be easier to explain than you might think…

First off store “shelf price labels” have gone E-Paper rather than be printed out and stuck on the front of the shelf as they used to be. They are sold as saving time and money (though the jury might be out for quite some time).

If you think about it a “one time price label” is in many ways the same as a “one time licence plate”.

Once you’ve “made the technology” changing it to do what on the surface is the same job is just a tiny change in a business model.

More interestingly it can be sold as “more secure” simply by having a hand unit/scanner that reads the vehicles VIN into the system to associate with the licence plate.

I can think of a whole load of other desirable sales features, including the various ways to reduce costs.

So unless people “understand” and most don’t then fundamental, foundational, failings, will cause the house of cards to fall.

The most fundamental problem of all is it is not possible in an “Off Line System” to,

“Tie an information object to a physical object.”

People keep trying and as we see with National and Similar ID Card systems they keep failing.

As the first Woman to head the UK MI5 Homeland Security Service Stella Rimington made the observation that there actually was no way to prove who you are.

The joke of ID is the “Birth Certificate” from which all else outgrows. Usually through the “Pass Port” or in more backwards places the “Drivers Licence” all of which have no actual tie to an individual as they are basically “Data Base Systems” in which the entries can be changed at the will of those who control it.

Now replace a nearly unique human being with a very far from unique mechanical device. The only measurable difference between then is a serial number –the VIN for a vehicle– applied at the factory.

Can the serial number be changed or falsified, as far as I’m aware as far as physical macro systems the answer is always “Yes” it’s just the difficulty involved.

So the “Licence Plate” is easily changeable and designed to be so, and the VIN number somewhat less so, but as crooks know sufficiently so to pass human sense verification.

It kind of makes things a “moot point” and you can be sure that quite a few officials are all to aware of this.

Do they care?

The answer is “NO” providing two things are true,

1, It’s not to easy to make a change.
2, The fact it can be changed is not widely known.

So the answer about licence plates is,

“It is at best security by obscurity”

Because that is “low cost” and “minimal hassle”.

Even going to a fully “online system” will not change the fact that the backend database can be changed at will by anyone with sufficient authorization held by their “account”.

Which kind of should now tell you that it is a,

“Turtles all the way down”

Problem, thus has no sufficiently reliable solution.

Clive Robinson • December 19, 2024 12:59 AM

@ Agammamon, ALL,

With regards,

“Then there’s the ‘web 3.0’ crowd who think everything should always be online and something something blockchain.”

I was deliberately avoiding a direct mention of Web3 and blockcchain in my above, for the simple reason it tends to pull out a certain type of fanboi.

For fundamental reasons the most obvious three being,

1, It forces an “On Line” mode of behaviour that is at best unreliable where vehicles are concerned.
2, A blockchain even without a “proof of work” is still incredibly resource intensive to run.
3, A blockchain is also incredibly slow thus has a low transactional rate, even when being used in what is mainly a “read only” database systems.

But there is a less obvious problem. When things are resource bound and slow people look for ways around the limitation and that in turn creates other problems.

For those old enough and creaky enough an example was “Data Warehousing with central asymmetric push”. As an idea it’s still used but it causes time windows where inconsistencies can be leveraged such as in financial systems.

Worse is if the loop gets closed in some way… think for instance of an adaptive purchase system based on stock held values. Where the “On Line shop” feeds back sales into the pricing system that in turn effects the central DB that many assumed was isolated but in fact is not. You end up with a feedback loop that is in effect under the control not of the selling organisation but the buyers.

Such feedback loops occurre in all sorts of places where some form of rate control is applied. You get under and over shoot when the load on the system changes. Get the load changes wrong and the control system goes into a form of oscillation. Other issues cause other problems.

Due to the load and constraints blockchain causes the more likely such issues are to be exploitable by those with only minor hostile intent.