Chapter 8

Multilateral Security

Information flowing across boundaries

Multilateral Models

CompartmentationChinese wallBMA (British Medical Association)

Develop system to track from conception to autopsy

Policy consists of nine principles listed on pages 170-171

Pilot implementations of BMA are in service

Inference Control

If take name off of medical record is that enough?

Medicare keeps 3 sets of records Complete records Beneficiary encrypted Public access

Inference control first looked at in census data One record in 1000 made available Noise added Extreme values not included in averages

Theory of inference control

Query set size controlTrackersCell suppression

Which sometimes requires complementary cell suppression

Limit number of attributes of queryAudit based controlsRandomization

De-identification

It is hardIssues can be politically fraughtHow to pick out specific data in a sea of

information

Residual problem

Insurers get all the data in order to pay claim

They want to know who the most expensive doctors and patients are

These are politically charged issue that seldom have rational solutions

Medical records

Easy problem setting up system of access controls to the record can only be viewed by sensible number of staff

Harder problem statistical securityHardest problem managing interface

between the 2Specifically to medicine how to prevent

spread of payment information

Discussion articles

Current state of BMAGenetic database in IcelandInference cases

List of Resources

Multilateral securityhttp://csrc.nist.gov/nissc/2000/proceedings/

papers/202ra.pdfChinese Wall

http://www.gammassl.co.uk/topics/chinesewall.html

List of Resources

Inference controlhttp://www.parc.xerox.com/research/publica

tions/details.php?id=5264http://www.parc.xerox.com/research/publica

tions/files/5264.pdfhttp://www.informatik.uni-trier.de/~ley/db/co

nf/icsd/icsd2002.htmlhttp://www.iis.sinica.edu.tw/~tshsu/projects/

inf.html

List of resources

De-identificationhttp://www.mii.ucla.edu/dataserver-

documentation-features-de-identificationhttp://www.haifa.ibm.com/projects/

software/udip/index.htmlhttp://www.sunclinical.com/old%20site_back

%20up/about/privacy.htm