Every California marijuana shop might have to display this code to prove it’s legal

California could soon require cannabis retailers to display proof of their license in their storefront window.

What began as a campaign to get marijuana retailers to voluntarily display a Quick Response code, or QR code, last month has turned into a proposal for an emergency regulation requiring that display.

Customers could scan the QR code with their cell phones to check whether the store has a license from the state.

“The proposed regulations will help consumers avoid purchasing cannabis goods from unlicensed businesses by providing a simple way to confirm licensure immediately before entering the premises or receiving a delivery,” Bureau of Cannabis Control Chief Lori Ajax said in a statement. “These requirements will also assist law enforcement in distinguishing between legal and illegal transportation of cannabis goods.”

The move comes as the bureau and other law enforcement agencies move to crack down on the multi-billion-dollar cannabis black market in California.

The proposed regulation has not yet gone into effect.

The bureau must provide a five-working-day notice to the public. Then it must submit the emergency regulation proposal to the Office of Administrative Law. That could happen on Monday, according to a bureau spokesman.

Once the office publishes the proposed regulation as being under review, there will be a five-day formal public comment period.