Secure QR Code Scheme Using Nonlinearity of Spatial Frequency

Quick Response (QR) codes are rapidly becoming pervasive in our daily life because of its fast readability and the popularity of smartphones with a built-in camera. However, recent researches raise security concerns because QR codes can be easily sniffed and decoded which can lead to private information leakage or financial loss. To address the issue, we present mQRCode which exploit patterns with specific spatial frequency to camouflage QR codes. When the targeted receiver put a camera at the designated position (e.g., 30cm and 0deg above the camouflaged QR code), the original QR code is revealed due to the Moire phenomenon. Malicious adversaries will only see camouflaged QR code at any other position. Our experiments show that the decoding rate of mQR codes is 95% or above within 0.83 seconds. When the camera is 10cm or 15deg away from the designated location, the decoding rate drops to 0 so it's secure from attackers.