An amateur inventor has designed an easy to make DIY wallet that blocks RFID signals.

Dustin Kirk, a usability engineer for software firm Benefitfocus, has published the plans on his web page for anyone to try. He said the wallet can be built at minimal cost using duct tape and aluminium foil.

"It seemed to be pretty well known online that aluminium foil prevents the transmission of RFID signals," he writes.

"A quick test at my workplace using my badge confirmed this. The next step was to design a wallet with aluminium foil embedded inside."

Kirk, who adapted the design from a duct tape wallet he built, has tested the design using cards with integrated RFID tags. He reports successful signal blocking even when the wallet is half opened.