Plaintext-aware encryption

About: Plaintext-aware encryption is a research topic. Over the lifetime, 1980 publications have been published within this topic receiving 101775 citations. The topic is also known as: Plaintext awareness.

A Complete Public-Key Cryptosystem

Abstract: We present a cryptosystem which is complete for the class of probabilistic public-key cryp- tosystems with bounded error. Besides traditional encryption schemes such as RSA and El Gamal, this class contains probabilistic encryption of Goldwasser-Micali as well as Ajtai-Dwork and NTRU cryptosystems. The latter two are known to make errors with some small positive probability. To our best knowledge, no complete public-key cryptosystem has been known before, whether encryp- tion/decryption errors are allowed or not. At the same time, other complete primitives such as Levin's universal one-way function (1) have been known for a long time.

Matrix based cryptographic procedure for efficient image encryption

Abstract: In this paper we propose a cryptographic transformation based on matrix manipulations for image encryption. Substitution and diffusion operations, based on the matrix, facilitate fast conversion of plaintext and images into ciphertext and cipher images. The paper describes the encryption algorithm, discusses the simulation results and compares with results obtained from Advanced Encryption Standard (AES). It is shown that the proposed algorithm is capable of encrypting images eight times faster than AES.

On black-box reductions between predicate encryption schemes

Abstract: We prove that there is no black-box construction of a threshold predicate encryption system from identity-based encryption. Our result signifies nontrivial progress in a line of research suggested by Boneh, Sahai and Waters (TCC '11), where they proposed a study of the relative power of predicate encryption for different functionalities. We rely on and extend the techniques of Boneh et al. (FOCS '08), where they give a black-box separation of identity-based encryption from trapdoor permutations. In contrast to previous results where only trapdoor permutations were used, our starting point is a more powerful primitive, namely identity-based encryption, which allows planting exponentially many trapdoors in the public-key by only planting a single master public-key of an identity-based encryption system. This makes the combinatorial aspect of our black-box separation result much more challenging. Our work gives the first impossibility result on black-box constructions of any cryptographic primitive from identity-based encryption. We also study the more general question of constructing predicate encryption for a complexity class F, given predicate encryption for a (potentially less powerful) complexity class G. Toward that end, we rule out certain natural black-box constructions of predicate encryption for NC1 from predicate encryption for AC0 assuming a widely believed conjecture in communication complexity.

Secure and noise-free nonlinear optical cryptosystem based on phase-truncated Fresnel diffraction and QR code

Abstract: A novel secure and noise-free nonlinear optical cryptosystem based on phase-truncated Fresnel diffraction (PTFD) and QR code is proposed. In this paper, we introduce QR code to resist the noise which contaminates the retrievals of normal optical cryptosystems. The plaintext is transformed into a QR code and then the code is encrypted into a real-valued noise-like ciphertext by employing the PTFD-based cryptosystem. The two private encryption keys (EKs) are generated by the PTFD of a random amplitude mask with the two public keys. In the process of generating the EKs, just the amplitude in the Fresnel and output planes need to be recorded. There are no iterative calculations in the whole encryption and decryption process. Moreover, owing to the nonlinear operation of PTFD and the two generated private EKs, the proposed scheme is supposed to against existing attacks. Numerical simulations are carried out to demonstrate the validity and security of the proposed cryptosystem.