Using only publicly available information, we have been able to decrypt the service provider ID numbers in the 10% sample of Medicare Benefits Schedule (MBS) published recently at the Federal Government’s data.gov.au website. We did not decrypt Patient ID numbers.

This research work is aimed at understanding mathematical facts about encryption and anonymization, in order to ensure that the security of government data is preserved in the face of the inevitable efforts of external parties who may be prepared to break the law and attempt to re-identify the data. There are numerous benefits to open government data, but it’s important to understand the mathematical techniques for protecting that data, so that the benefits can be derived with a clear understanding that individual privacy is not breached.