Earticle

Fully homomorphic encryption (FHE) is a “holy grail” of cryptography. However, it is not yet adopted in practice because no known scheme is efficient. In this paper, we mainly focus on how to reduce the public key sizes in FHE. Based on Dijk et al.’s FHE scheme (DGHV) and Gentry’s fully homomorhpic technology, we propose two schemes with shorter public keys by encrypting with a combination of the public key elements to replace a linear form in DGHV scheme and a quadratic form in Coron et al.’s scheme. Compared with DGHV scheme and Coron et al.’s scheme, our schemes can greatly reduce the public key sizes, which make our schemes more efficient. Furthermore, we prove the security of our schemes based on difficulties of the approximate greatest common divisor (AGCD) problem and the sparse subset sum problem.

Cloud services have become state of the art of resource sharing and interoperability among different service providers. The federated cloud seek to reduce costs and maximize efficiency, provide flexible and reliable services composed of various external cloud service and internal services, but this would introduce a risk of security due to outsourcing. For organization which provide an integrity cloud service must rely on SLA to illustrate the capacity of risk and performance, the various providers involved in the federations or services compositions should effectively distribute the organizational responsibilities and SLA. To solve the fears and deal with the threats associated with outsourcing, new method for selection of outsourcing cloud service providers(CSP) based on assessment of security and performance is urgently needed. This paper presents an approach on how to select the proper CSP to guarantee organizational SLA, which quantify the SLA terms and calculate a security weight, the organization can choose the appropriate CSP based on security weight, meanwhile minimize the business cost. This paper make contribution on modeling the capacity of the CSP, considering the business cost and historical performance. The proposed approach is validated through case study that shows selected CSP through our approach can best meet the organizational security and cost needs.

Proxy Mobile IPv6 is a network-based mobility management protocol. The access authentication security plays the primary role in maintaining network security of proxy mobile IPv6. In this paper, we constructed an authentication framework, which is suitable for proxy mobile IPv6 and has eliminated the interaction between the access network and the home network. We implemented a mutual authentication between users and the access network by using hierarchical identity-based signature (HIBS) schemes and combining the identity-based signature and the real network environment based on proxy mobile IPv6. Also, we have enhanced the function of LMA to make it able to optimize the authentication function of proxy mobile IPv6 protocol by reusing historical authentication information. By results from security analysis, this scheme is secure.

Cloud computing platforms are usually constructed as trusted virtual platforms based on trusted computing technologies. This is one of the most effective approaches to resolve cloud computing security problems. However, the protection of sensitive data in trusted virtual platforms is an important problem needed to be resolved. In this paper, we proposed a novel authorization protocol. The protocol assembled the functions of OIAP, OSAP and AACP protocols, and prevented all known attacks in existing authorization protocols. Moreover, it satisfied the property of exclusivity and was compatible with TCG TPM command formats. The protocol effectively protects the sensitive data from unauthorized accesses in trusted cloud computing platforms.

Steganography, the idea of hiding messages and data within other pieces of data, can be useful in many real world applications alongside encryption and other code-writing methods. Data hiding methods are a new kind of technology in secret communication. Multimedia objects like audio are the most used in today’s information hiding systems. Audio file due to its high degree of redundancy and high data transmission rate can create a good hiding medium. Several formats such as MP3 have been used in audio data steganography. Varieties of methods have been established for embedding data in digital audio. In this article, in addition to more emphasis on MPEG-1 layer III (MP3) steganography methods with thorough information about weaknesses and strengths of these techniques, we present a complete study of audio file steganography approaches.