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 new chaos-based secure image encryption scheme using multiple substitution boxes

Abstract: Due to development in Internet and networking technology, multimedia data is broadly transmitted via wired and wireless medium. Thus security is a major concern in modern communication systems. Encryption is one of the pre-eminent ways to guarantee security in many real time applications. In this paper, confusion and diffusion phenomenon is presented for digital images. The proposed scheme provides a secure image encryption/decryption scheme using two chaotic maps and substitution boxes. To confuse the relationship between plaintext and ciphertext images, both chaotic maps play a vital role in the confusion and diffusion process. In confusion process, the plaintext image is permuted row-wise and column-wise via two random sequences generated by Henon map. The pixel values diffusion is carried out by unimodel Skew tent map through XOR operation. Furthermore, in last step of the proposed scheme, image is divided into four blocks. To get a highly diffused ciphertext, four different Substitution Boxes (S-Boxes) are applied on each block. Extensive security analysis show that the proposed scheme provides an efficient security for digital images.

A Timed-Release Proxy Re-Encryption Scheme

Abstract: Timed-Release Encryption (TRE) is a kind of time-dependent encryption, where the time of decryption can be controlled. More precisely, TRE prevents even a legitimate recipient decrypting a ciphertext before a semi-trusted Time Server (TS) sends trapdoor sT assigned with a release time T of the encryptor's choice. Cathalo et al. (ICICS2005) and Chalkias et al. (ESORICS2007) have already considered encrypting a message intended for multiple recipients with the same release time. One drawback of these schemes is the ciphertext size and computational complexity, which depend on the number of recipients N. Ideally, it is desirable that any factor (ciphertext size, computational complexity of encryption/decryption, and public/secret key size) does not depend on N. In this paper, to achieve TRE with such fully constant costs from the encryptor's/decryptor's point of view, by borrowing the technique of Proxy Re-Encryption (PRE), we propose a cryptosystem in which even if the proxy transformation is applied to a TRE ciphertext, the release time is still effective. By sending a TRE ciphertext to the proxy, an encryptor can foist N-dependent computation costs on the proxy. We call this cryptosystem Timed-Release PRE (TR-PRE). This function can be applied to efficient multicast communication with a release time indication.

Scheme for fast realization of encryption, decryption and authentication

Abstract: A new scheme for fast realization of encryption, decryption and authentication which can overcome the problems of the RSA cryptosystem is disclosed. The encryption obtains a ciphertext C from a plaintext M according to C ~ M e (mod n) using a first secret key given by N (~ 2) prime numbers p1, p2, ~, p N, a first public key n given by a product p1 k1p2 k2 ~ p N kN where k1, k2, ~, kN are arbitrary positive integers, a second public key a and a second secret key d which satisfy ed ~ 1 (mod L) where L is a least common multiple of p1-1, p2-1, ~, pN-1. The decryption recovers the plaintext M by obtaining residues M p1k1, M p2k2, ~, M pNkN modulo p1k1, p2k2, ~, p NkN, respectively, of the plaintext M using a prescribed loop calculation with respect to the first secret key p1, p2, ~, p N, and by applying the Chinese remainder theorem to the residues M p1k1, M p2k2, ~, M pNkN. This encryption/decryption scheme can be utilized for realizing the authentication.