Steganography of Encrypted Messages Inside Valid QR Code

Steganography is regarded as the primary defense mechanism in information security, as it conceals a secret message (payload) within an innocuous file (container) to transfer the payload without detection by an adversary. Steganographic systems utilize the container solely for the purpose of hiding the payload. In this paper, we introduce a steganographic system that employs the container not only to conceal the payload but also to provide misleading information to the adversary. To accomplish this objective, we utilize a quick response (QR) code as the container. The QR codes produced by our proposed system can convey their standard message alongside the payload. While anyone can access the message, the payload can only be retrieved using a secret key. The message and the payload are independent; that is, any message can be created irrespective of the payload and vice versa. We can leverage this by crafting a message that misleads the adversary. We evaluate the proposed system and demonstrate that the generated QR code is valid, meaning it is indistinguishable from a standard QR code, which renders it seemingly harmless and less vulnerable to adversarial attacks. Furthermore, it is space-efficient, possesses an acceptable degree of noise immunity, and is resistant to steganalysis attacks.