This study proposes a self-adaptive image encryption algorithm based on the quantum logistic map. First, the initial values are substituted into the quantum logistic map based on an iteration process to generate three random sequences. After preprocessing, three new random sequences with better randomicity were obtained from the generated random sequences. In particular, the correlation coefficients for random sequences before and after preprocessing are compared to determine the best model to make the correlation coefficients closer to zero. Second, one random sequence in the scrambling stage is selected with respect to the plain image. The selected random sequence is then used to perform row-column perturbation on the plain image. Finally, the remaining two random sequences are used to perform forward and reverse diffusion to obtain the final cipher image. Because of the dependence on the plain image, the algorithm can frustrate the chosen-plaintext and known-plaintext attacks. Experimental results show that the proposed encryption algorithm can achieve secure communications.

Attribute-based encryption (ABE) provides a mechanism for complex access control over encrypted data. However in most ABE systems, the ciphertext size and the decryption overhead, which grow with the complexity of the access policy, are becoming critical barriers in applications running on resource-limited devices. Outsourcing decryption of ABE ciphertexts to a powerful third party is a reasonable manner to solve this problem. Since the third party is usually believed to be untrusted, the security requirements of ABE with outsourced decryption should include privacy and verifiability. Namely, any adversary including the third party should learn nothing about the encrypted message, and the correctness of the outsourced decryption is supposed to be verified efficiently. We propose generic constructions of CPA-secure and RCCA-secure ABE systems with verifiable outsourced decryption from CPA-secure ABE with outsourced decryption, respectively. We also instantiate our CPA-secure construction in the standard model and then show an implementation of this instantiation. The experimental results show that, compared with the existing scheme, our CPA-secure construction has more compact ciphertext and less computational costs. Moreover, the techniques involved in the RCCA-secure construction can be applied in generally constructing CCA-secure ABE, which we believe to be of independent interest.

We introduce the notion of complementary-witness-soundness for a witness indistinguishable proof system. We then present a new general framework for public key encryption schemes, denoted as CWSWI-type encryption, based on a complementary-witness-sound witness indistinguishable (CWSWI) proof system. The construction of a CWSWI-type encryption scheme is relatively straightforward, while the security thereof against adaptive chosen ciphertext attack (denoted CCA2) can be rigorously proven. Many existing CCA2 public key encryption schemes can be interpreted as being of CWSWI-type, including the schemes of Lindell, Cramer-Shoup and Peikert-Waters. Thus, our CWSWI approach provides a novel means for designing and analysing CCA2 secure public key encryption schemes.

Abstract In Identity‐Based Encryption (IBE) systems, there is a widespread concern over the issue on how to provide an efficient revocation mechanism. We develop a new approach in constructing an efficient revocable IBE scheme. Our approach utilizes recent advances in multilinear maps and combines a two‐level hierarchical IBE scheme with a revocation encryption system. In our revocable IBE scheme, both the public parameters and the private key are constant‐size. Simultaneously, the size of the update key at some time is only proportional to the number of revoked users at the time. Our proposed scheme is proven secure in the selective revocation list model without relying on random oracles. Copyright © 2015 John Wiley & Sons, Ltd.

We describe a new encryption technique that is secure in the standard model against chosen ciphertext attacks. We base our method on two very efficient Identity-Based Encryption (IBE) schemes without random oracles due to Boneh and Boyen, and Waters.Unlike previous CCA2-secure cryptosystems that use IBE as a black box, our approach is very simple and compact. It makes direct use of the underlying IBE structure, and requires no cryptographic primitive other than the IBE scheme itself. This conveys several advantages. We achieve shorter ciphertext size than the best known instantiations of the other methods, and our technique is as efficient as the Boneh and Katz method (and more so than that of Canetti, Halevi, and Katz). Further, our method operates nicely on hierarchical IBE, and since it allows the validity of ciphertexts to be checked publicly, it can be used to construct systems with non-interactive threshold decryption.In this paper we describe two main constructions: a full encryption system based on the Waters adaptive-ID secure IBE, and a KEM based on the Boneh-Boyen selective-ID secure IBE. Both systems are shown CCA2-secure in the standard model, the latter with a tight reduction. We discuss several uses and extensions of our approach, and draw comparisons with other schemes that are provably secure in the standard model.