MoireComm: Secure Screen-camera Communication Based on Moire Cryptography

Quick Response (QR) codes have become increasingly popular for screen-camera communication due to their swift readability and widespread smartphone use. Nevertheless, they are vulnerable to privacy invasions from unauthorized photography. Addressing this, we propose a novel Moire encryption ´ technique-based secure screen-camera communication system, named MoireComm. The Moir ´ e encryption can enhance security ´ by using distinct spatial frequency patterns for camouflage. The original QR code is revealed as a Moire pattern only when the ´ camera in a designated position, e.g., directly in front and 30 cm from the screen. From any other positions, only the camouflaged QR code can be seen. Decryption schemes are customized for different scenarios. The multi-frame approach achieves a decryption success of over 98.6% within 13.2 frames in handheld scenarios. Conditional generative adversarial network (cGAN)- based decryption method decodes the Moire QR code images with ´ a 98.8% success rate in 0.02 s within three frames and is also applicable in handheld scenarios. For fixed screen-camera setups, our fast decryption scheme achieves 99.4% success within two frames, with average 0.4 s latency. Significantly, the decryption rate plunges to 0% for surveillance cameras displaced by 20° or more than ≥10 cm from the target position, demonstrating MoireComm's resilience against attacks.