The Reincarnation of Grille Cipher: A Generative Approach
This work addresses the challenge of secure communication by integrating cryptography and steganography, though it appears incremental as it builds on existing concepts like the Cardan grille and generative adversarial networks.
The paper tackled the problem of constructing a cipher that simultaneously ensures both channel and content security for secure communication, presenting a new generative framework for grille cipher that uses a digital Cardan grille for encryption and decryption, with experimental results showing promising performance.
In order to keep the data secret, various techniques have been implemented to encrypt and decrypt the secret data. Cryptography is committed to the security of content, i.e. it cannot be restored with a given ciphertext. Steganography is to hiding the existence of a communication channel within a stego. However, it has been difficult to construct a cipher (cypher) that simultaneously satisfy both channel and content security for secure communication. Inspired by the Cardan grille, this paper presents a new generative framework for grille cipher. A digital cardan grille is used for message encryption and decryption. The ciphertext is directly sampled by a powerful generator without an explicit cover. Message loss and prior loss are proposed for penalizing message extraction error and unrealistic ciphertext. Jensen-Shannon Divergence is introduced as new criteria for channel security. A simple practical data-driven grille cipher is proposed using semantic image inpainting and generative adversarial network. Experimental results demonstrate the promising of the proposed method.