Buckinghamshire CC ANPR cameras

[Ian Mason]

On 9 Jan 2012, at 17:32, Roland Perry wrote:

> In article <4F0B222B.9090406 at zen.co.uk>, Peter Fairbrother <zenadsl6186 at zen.co.uk 
> > writes
>> If the hash function is such that the hash changes say every day,  
>> or better for every rush hour, then very little private data would  
>> be available.
>
> I seems it isn't.
>
> But if one has access to the output data, then it occurs to me that  
> an easy attack on the hash function (for a particular plate) would  
> be to drive a car, with that as a false numberplate, past a camera  
> at 3am, then looking at the results in the morning.

Or to put it in cryptographic terms - a known plaintext attack with  
complexity of O(1). When put like that, it's so starkly ineffective a  
protection it amounts to no protection at all.