[Dataloss] NY laptop theft breaches no data protection rules

[Mike Simon]

Chris is right of course. As a trivial example, it would be simple to 
reverse the codes for blood type from this sample. Blood type for this 
population is a solid statistical model and this is enough samples that 
one could derive which column is blood types and what the codes are by 
doing simple statistical analysis of the given data.

Given that and the sample size, it seems likely that other disease codes 
could be reversed in exactly the same way, especially given the 
specificity of the population base. This isn't advanced statistical 
attacks on a cipher, just high school math.



-----Original Message-----
From: Chris Walsh [mailto:chris at cwalsh.org] 
Sent: Wednesday, February 27, 2008 8:00 AM
To: lyger
Cc: dataloss at attrition.org
Subject: Re: [Dataloss] NY laptop theft breaches no data protection 
rules

I am interpreting "encryption", in light of what is said below, to mean 
"use of consistent and obscure codes".  Basically, something akin to a 
"q code".


If I understand this properly, a decoded record might look like this:

Chris           Walsh            123 Main St  Dublin   AB-    HIV+


Whereas the "encrypted" variant is:
Chris           Walsh            123 Main St  Dublin   785    432


Since the ITBS never told NY that "785" is the code for "AB-" and "432" 
means
"HIV+", adequate protection of this sensitive information was in place.

I won't argue with that conclusion, although it would be easy to.  
I will say that calling a simple code such as this "encryption"was 
unfortunate, and tends to perpetuate misunderstandings.

Lastly, "It is not possible to isolate individual fields in the log 
files,
so it would have been difficult, if not impossible, to have anonymised 
the 
files prior to their supply to the NYBC" means they could not parse 
their 
own logs. That's interesting.  


On Wed, Feb 27, 2008 at 02:52:03PM +0000, lyger wrote:
> The loss of a laptop containing the files of up to 175,000 Irish blood 

> donors, which was stolen earlier this month in New York, does not 
> constitute a breach of the Data Protection Acts and the encryption on 
the 
> laptop is sufficient to protect the files, Ireland.s Data Protection 
> Commissioner said today.
> 
[snip]

> The log files also contain numeric codes for other kinds of 
> information such as attendance at the IBTS or blood-test results 
performed 
> by the IBTS.
> 
> "Importantly, the key for these codes was not on the stolen laptop or 
on 
> the disks given to the NYBC for the performance of its functions," the 

> Commission said.
> 
> "It is not possible to isolate individual fields in the log files, so 
it 
> would have been difficult, if not impossible, to have anonymised the 
files 
> prior to their supply to the NYBC. Accordingly, the amount of personal 

> data supplied to the NYBC for the performance of the contract entered 
into 
> is not considered excessive in the circumstances," the Commission 
said.
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