Speckle-based optical cryptosystem and its application for human face recognition via deep learning
This work addresses privacy concerns in face recognition by offering a high-security hardware-based encryption method, though it is incremental as it builds on existing optical cryptosystems with improved efficiency and compatibility.
The authors tackled the problem of securing face images in recognition systems by proposing a speckle-based optical cryptosystem that encrypts images at light speed using gigabit-length physical keys, achieving up to 98% accuracy in face recognition after decryption via a neural network.
Face recognition has recently become ubiquitous in many scenes for authentication or security purposes. Meanwhile, there are increasing concerns about the privacy of face images, which are sensitive biometric data that should be carefully protected. Software-based cryptosystems are widely adopted nowadays to encrypt face images, but the security level is limited by insufficient digital secret key length or computing power. Hardware-based optical cryptosystems can generate enormously longer secret keys and enable encryption at light speed, but most reported optical methods, such as double random phase encryption, are less compatible with other systems due to system complexity. In this study, a plain yet high-efficient speckle-based optical cryptosystem is proposed and implemented. A scattering ground glass is exploited to generate physical secret keys of gigabit length and encrypt face images via seemingly random optical speckles at light speed. Face images can then be decrypted from the random speckles by a well-trained decryption neural network, such that face recognition can be realized with up to 98% accuracy. The proposed cryptosystem has wide applicability, and it may open a new avenue for high-security complex information encryption and decryption by utilizing optical speckles.