Re: [Gnumed-devel] experiments with gnumed - multiusers vnc, importing an au emr

[Karsten Hilbert]

On Thu, Apr 20, 2006 at 09:47:54AM +0800, Syan Tan wrote:

> thinking about it, the only correct thing to do seems to be to preserve the
> structure of the instance data and the health issue + episode headings, but to
> scramble the text with word substitution, as well as name substitution, date
> fudging, and address random relinking . would that be de-identified enough ?
Well, I tend to think that "de-identified enough" is a range
from "acceptably so" to "beyond use" rather than a cutoff.
The exact value used within that range depends on what sort
of protection you need.

Yes, if you want to hide a patient's data securely from your
fellow doctor next door you will have to scamble the medical
content, too, as she might be able to match "real patient"
to "problems/operations listed" by her own medical skills
and thereby gain knowledge via the now re-identified EMR.

But if you want to protect a patient's privacy from, say,
me, it's enough to falsify the identities. I do not have
access to your patients. I also have no idea how to find out
who your patients actually are in order to start matching
EMRs to patients. Hence proper protection is ensure, I dare
say. It is akin to not storing patient names with any
medical data and hold the EMR ID <-> patient identity
mapping elsewhere in a secure space (say, the patient's
brain).

In a recent discussion on the openhealth list this topic was
chanced upon and the OpenEHR guys thought the latter
approach would be the most secure that's practically useful
- and they were talking real live patient data in actual
care.

> BTW a bzip2 openssl blowfish encrypted pg_dump is about 21M.
Fine. If public/private encryption of the entire thing is
too large then do so with a large and very random one-time
session key which you sent to me and symmetrically encrypt
the data with that. I have no problem downloading 100 MB
from somewhere.

Karsten
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