Ann Cavoukian, a world-leading privacy expert, has resigned as an adviser to Sidewalk Labs on its proposed Toronto smart city development. Cavoukian sent a letter advising the company of her resignation Friday.

In the letter, she expressed concerns regarding Sidewalk Labs recent digital governance proposals, specifically, the possibility that not all personal data would be de-identified at the source—a concern she said she raised with Sidewalk Labs early last month. Sidewalk Labs told The Logic it is committed to de-identifying data, but that it can’t control what third-parties do.

“With all due respect,” she wrote about data not being de-identified at source, “that is not acceptable.”

“If personally identifiable data are not de-identified at source, we will be creating another central database of personal information (controlled by whom?), that may be used without data subjects’ consent, that will be exposed to the risks of hacking and unauthorized access,” she said in her statement. “As we all know, existing methods of encryption are not infallible and may be broken, potentially exposing the personal data of Waterfront Toronto residents! Why take such risks?”