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 secure and efficient Ciphertext-Policy Attribute-Based Proxy Re-Encryption for cloud data sharing

Abstract: Proxy Re-Encryption (PRE) is a useful cryptographic primitive that allows a data owner to delegate the access rights of the encrypted data stored on a cloud storage system to others without leaking the information of the data to the honest-but-curious cloud server. It provides effectiveness for data sharing as the data owner even using limited resource devices (e.g. mobile devices) can offload most of the computational operations to the cloud. Since its introduction many variants of PRE have been proposed. A Ciphertext-Policy Attribute-Based Proxy Re-Encryption (CP-ABPRE), which is regarded as a general notion for PRE, employs the PRE technology in the attribute-based encryption cryptographic setting such that the proxy is allowed to convert an encryption under an access policy to another encryption under a new access policy. CP-ABPRE is applicable to many network applications, such as network data sharing. The existing CP-ABPRE systems, however, leave how to achieve adaptive CCA security as an interesting open problem. This paper, for the first time, proposes a new CP-ABPRE to tackle the problem by integrating the dual system encryption technology with selective proof technique. Although the new scheme supporting any monotonic access structures is built in the composite order bilinear group, it is proven adaptively CCA secure in the standard model without jeopardizing the expressiveness of access policy. We further make an improvement for the scheme to achieve more efficiency in the re-encryption key generation and re-encryption phases. This paper proposes a new Ciphertext-Policy Attribute-Based Proxy Re-Encryption scheme.The scheme is proved adaptively chosen ciphertext secure by leveraging dual system encryption technology and selective proof technique.The paper also proposes an improvement for re-encryption key generation and re-encryption phases so as to reduce computational and communication cost.

Fast RSA-Type Cryptosystem Modulo pkq

Abstract: We propose a cryptosystem modulo p k q based on the RSA cryptosystem. We choose an appropriate modulus p k q which resists two of the fastest factoring algorithms, namely the number field sieve and the elliptic curve method. We also apply the fast decryption algorithm modulo p k proposed in [22]. The decryption process of the proposed cryptosystems is faster than the RSA cryptosystem using Chinese remainder theorem, known as the Quisquater-Couvreur method [17]. For example, if we choose the 768-bit modulus p 2 q for 256-bit primes p and q, then the decryption process of the proposed cryptosystem is about 3 times faster than that of RSA cryptosystem using Quisquater-Couvreur method.

Answering aggregation queries in a secure system model

Abstract: As more sensitive data is captured in electronic form, security becomes more and more important. Data encryption is the main technique for achieving security. While in the past enterprises were hesitant to implement database encryption because of the very high cost, complexity, and performance degradation, they now have to face the ever-growing risk of data theft as well as emerging legislative requirements. Data encryption can be done at multiple tiers within the enterprise. Different choices on where to encrypt the data offer different security features that protect against different attacks. One class of attack that needs to be taken seriously is the compromise of the database server, its software or administrator. A secure way to address this threat is for a DBMS to directly process queries on the ciphertext, without decryption. We conduct a comprehensive study on answering SUM and AVG aggregation queries in such a system model by using a secure homomorphic encryption scheme in a novel way. We demonstrate that the performance of such a solution is comparable to a traditional symmetric encryption scheme (e.g., DES) in which each value is decrypted and the computation is performed on the plaintext. Clearly this traditional encryption scheme is not a viable solution to the problem because the server must have access to the secret key and the plaintext, which violates our system model and security requirements. We study the problem in the setting of a read-optimized DBMS for data warehousing applications, in which SUM and AVG are frequent and crucial.

On the Achievability of Simulation-Based Security for Functional Encryption

Abstract: This work attempts to clarify to what extent simulation-based security (SIM-security) is achievable for functional encryption (FE) and its relation to the weaker indistinguishability-based security (IND-security). Our main result is a compiler that transforms any FE scheme for the general circuit functionality (which we denote by Circuit-FE) meeting indistinguishability-based security (IND-security) to a Circuit-FE scheme meeting SIM-security, where: