A two level cryptography scheme based on QR code and logistic mapping

Quick Response (QR) code, a two-dimensional graphic of square symbols, is widely applied due to its reliability, fast scanning, large data capacity and error correction. But its security has become a concern. From the perspective of information hiding, QR codes can transmit secret information. This paper presents a steganography scheme with two-layer information storage for protecting two secrets. The first layer uses the logistic mapping algorithm for the secret QR code image, and the second layer embeds another secret message into the QR code image via a reversible steganography algorithm. The contaminated transmission image doesn’t affect the extraction of the QR code image and the first layer of secret information. Even if the first layer’s hiding is broken, the second layer’s secret is unaffected. Combining QR code advantages and logistic chaotic mapping randomness, this scheme has low computational complexity, high interference robustness and large payload capacity. Theoretical analysis proves its effectiveness. Experimental results show it offers multiple encryption protection and decryption methods for two pieces of information and has many advantages over existing schemes.