Improved diffractive-imaging based image encryption scheme in 3D space

Abstract

In this paper, we present an improved diffractive-imaging-based image encryption scheme in 3D space. In this cryptosystem, the plaintext is divided into several sub-images by binary amplitude masks and then diffused into 3D space at different axial positions for encryption, which confuses the relation between the plaintext and the ciphertext to make the chosen-plaintext attack no longer work. For the decryption, we develop a modified iterative retrieval algorithm to retrieve a decrypted image with high quality. Additionally, this cryptosystem obtains higher security without increasing the amount of the ciphertext. Compared with previous diffractive-imaging-based image encryption schemes, the key space is enlarged so greatly that this cryptosystem can resist the brute force attack. Furthermore, this scheme can significantly reduce the computation and retrieve a decrypted image with high-quality.