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Reversible data hiding with contrast enhancement (RDH-CE) is proposed to aim at improving the contrast of images while embedding data. After deeply analyzing and studying the RDH-CE method proposed by Jafar et al., it is found that there are three main problems in their method. Firstly, their method ignores the fact that the left-bottom neighbors of a pixel contribute to increasing the accuracy of the local-complexity evaluation. Secondly, Jafar et al.’s method employs K-means clustering in combination with one single feature to split pixels into five classes, leading to a weak clustering performance. Finally, Jafar et al.’s method uniformly embedded 1 bit into each pixel irrespective of the local complexity, and thus, the embedding capacity is limited. To this end, an improved RDH-CE method is proposed in this paper. Considering that the complexity evaluation plays a vital role in both contrast enhancement and payload increase, we improve embedding performance by including left-bottom neighbors of a pixel into complexity evaluation. Compared with one single feature in Jafar et al.’s method, we extract multiple features to assist K-means clustering such that a better cluster performance is obtained. In addition, our method provides an adaptive pixel modification strategy based on the local complexity, in which we can adaptively embed 1 or 2 bits into a pixel according to the corresponding complexity. By these three improvements, our method is capable of achieving high capacity while enhancing contrast. The experimental results also show that our method achieves higher accuracy of the complexity evaluation, larger payload, and better local contrast enhancement than those existing RDH-CE related methods. [ABSTRACT FROM AUTHOR]

Secret sharing is a useful method which divides a secret message into several shares for security. During the recovery procedure, only when sufficient shares are obtained, the secret message can be recovered. This paper proposes two novel reversible data hiding schemes in encrypted image via secret sharing over Galois fields ${{GF}}{({p})}$ and ${{GF}}{(}{{2}^{{8}}}{)}$. The content owner first applies a specific encryption method through block and pixel permutation and Shamir’s secret sharing. Then, the theoretical demonstration is introduced to explain that the generated shares are suitable for data embedding over ${{GF}}{({p})}$ and ${{GF}}{(}{{2}^{{8}}}{)}$. Finally, two embedding algorithms over ${{GF}}{({p})}$ and ${{GF}}{(}{{2}^{{8}}}{)}$ are presented, and on the receiver side, with different keys, additional data can be extracted correctly and original image can be recovered losslessly. Experimental results show that our schemes can achieve better rate-distortion performance than some state-of-the-art schemes. [ABSTRACT FROM AUTHOR]

The Intelligent Transportation System (ITS) provides more possibilities for the realization of smart cities by integrating the Internet of Things (IoT) and cloud computing. However, how to ensure security of IoT data stored in the cloud has become one of the biggest challenges at present. As a promising solution for realizing fine-grained access control, Ciphertext-Policy Attribute-Based Encryption (CP-ABE) can be used to ensure data security. However, the traditional CP-ABE schemes may leak privacy of ITS users. Moreover, due to their high computational overheads, the current privacy-preserving techniques are not suitable for IoT lightweight devices. To fill this gap, this article presents ABE-FPP, a lightweight attribute-based access control scheme with full privacy protection (FPP), which can achieve full privacy protection in the three key stages (i.e., key generation, access control, and partial decryption), while reducing consumption overhead on the user side. Specifically, to protect privacy during key generation, a lightweight two-party secure computing protocol between the user and the authority is designed to generate secret keys; to protect privacy during the access control policy setting, we present an efficient policy hidden strategy, which only reveals attribute names and efficiently hides attribute values; to protect privacy during partial decryption, we propose a hybrid authentication method that does not need to submit attribute values to the cloud. Moreover, to achieve lightweight computation for IoT devices, online/offline encryption and outsourced decryption are employed in ABE-FPP. Finally, formal security proofs show that our scheme is secure in the standard model. The asymptotic complexity analyses and experimental results demonstrate that the presented scheme achieves higher computation efficiency than the state-of-the-art ones. [ABSTRACT FROM AUTHOR]

With the technology of data storage and shared services in the cloud, users can easily share data or revoke from their groups. To ensure the accuracy of the shared data, the key is used for group users to calculate the authenticators of the shared data and audit the data's integrity remotely. However, high-speed mobile terminals have posed challenges to key management in Vehicle Ad-hoc networks (VANETs). Besides, to maintain the integrity of the shared data, the computation and communication overheads must be increased in the revocation process when a vehicle user is removed from a group. For such, a new shared data auditing scheme is proposed in this paper, which supports user revocation by combining the existing certificateless signcryption method with a fog architecture. This scheme improves the efficiency of auditing and user revocation since it reduces many time-consuming operations, as well as features such as public auditing, mutual authentication, efficient and secure revocation are presented. Security analysis and experimental results demonstrate that the proposed scheme is both correct and safe, has more comprehensive functions and better efficiency than other existing ones. [ABSTRACT FROM AUTHOR]

As a critical parameter in evaluating the reliability of a multiprocessor system when processors malfunction, the \boldsymbol $h$ -extra connectivity ($h$ -EC) of a multiprocessor system modeled by a graph $G$ , denoted by $\kappa ^{(h)}_{o}(G)$ , is an $h$ -extra vertex-cut with minimum cardinality. Both of the $h$ -extra conditional diagnosability ($h$ -ECD) and the $t/h$ -diagnosability of the multiprocessor system are vital to tolerate and diagnose faulty processors. These two parameters rely on the resolving of $h$ -EC. For the multiprocessor system based on star graph $S_{n}$ , we show that the 5-EC $\kappa ^{(5)}_{o}(S_{n})$ of $S_{n}$ ($n\geq 5$) is $6n-18$. As a by-product, we present a novel proof of $\kappa ^{(2)}_{o}(S_{n})=3n-7$ (resp., $\kappa ^{(4)}_{o}(S_{n})=5n-14$) by relaxing the restriction $n\geq 10$ (resp., $n\geq 7$) to $n\geq 5$ (resp., $n\geq 5$). Furthermore, we determine that the $h$ -ECD of $S_{n}$ $(n\geq 5)$ under the preparata, metze, and chien (PMC) model is $(h+1)n-2h-1$ for $1\leq h\leq 3$ and $(h+1)n-3h+2$ for $4\leq h\leq 5$. In addition, we show that $S_{n}$ is $[(h+1)n-4h+2]/h$ -diagnosable for $4\leq h\leq 5$ , which extends the result that $S_{n}$ is $[(h+1)n-3h-1]/h$ -diagnosable for $1\leq h\leq 3$ by [Zhou et al. “The t/k-diagnosability of star graph networks,” IEEE Trans. Comput., vol. 64, no. 2, pp. 547–555, Feb. 2015]. [ABSTRACT FROM AUTHOR]

The rapid development of network technology and the advent of various smart devices can cause the rapid growth of network data traffic in the hot areas. However, the existing cellular network capacity cannot meet the needs of network users. Therefore, the small cellular base stations (SCBSs) are proposed and widely used. Nevertheless, the physical cell identifications (PCI) are extremely limited, thus it is difficult to reasonably allocate the limited PCIs to the massive SCBSs, which greatly affect the quality of service (QoS) for users in hot areas. In this paper, a PCI allocation and reuse scheme based on the maximum degree first coloring (MDFC) algorithm is proposed to allocate the limited PCIs for SCBSs in hot areas. Moreover, the K-means clustering algorithm is adopted to divide and identify different hot areas with the mobility data of massive users, which also contributes to the allocation of PCIs. The proposed scheme reduces the rate of PCI conflict and confusion, and improves the users’ QoS. Simulation results show that the MDFC algorithm has better PCI allocation efficiency, and shorter PCI allocation time. Thus, it is more suitable for the deployment of cellular networks in hot areas. [ABSTRACT FROM AUTHOR]

Outsourcing of encrypted smart body sensor network data to the edge or the cloud is now an entrenched practice within organizations, for example to reduce cost and enhance productivity (to some extent), while ensuring data is not accessible to misbehaving cloud service providers. Although there are a large number of searchable symmetric encryption schemes designed to support searching operations on encrypted data, a fully functional and memory leakage-resilient scheme for smart body sensor network data is lacking. This security property is highly desirable as the resource-sharing environment may be prone to various kinds of memory leakage. In this paper, a memory leakage-resilient dynamic and verifiable multi-keyword ranked search scheme (MLR-DVMRS) on encrypted smart body sensor network data is proposed. As each sensor device has inherent characteristics to identify itself, this property can be used to authenticate the device. The proposed scheme utilizes physically unclonable functions and fuzzy extractors to achieve memory leakage-resilience. Meanwhile the vector space model, TF-IDF measure method, and order-preserving encryption, are used to achieve dynamic and multi-keyword ranked search functionalities. A formal security analysis is given to prove the security of MLR-DVMRS. Besides the comprehensive functionalities of MLR-DVMRS, experimental results demonstrate that the efficiency of MLR-DVMRS is superior to MRSE (a multi-keyword ranked search over encrypted cloud data scheme) for large data collection. [ABSTRACT FROM AUTHOR]

Steganography based on bitrate modulation is a new type of information hiding approach for Voice over IP (VoIP), which can naturally resist state-of-the-art steganalysis schemes, due to inducing no modifications on the involved protocols and payloads of VoIP packets. To fill this gap, this letter presents a new corresponding detection scheme. Specifically, for the existing three methods based on bitrate modulation, we first reveal obvious regularities for the change intervals of bitrates in steganographic frame streams, which are totally different from the normal streams. Furthermore, exploiting the statistical properties of change intervals, we design a support-vector-machine-based steganalysis scheme. We evaluate the detection performance of the proposed scheme, respectively, with three state-of-the-art rate adaptation algorithms as the generators of normal VoIP streams. The results demonstrate that the proposed scheme can effectively detect the existing three bitrate modulation-based steganographic methods, even at relatively low covert bandwidths. [ABSTRACT FROM AUTHOR]

With the rapid popularity of social network applications and advanced digital devices, we have witnessed the explosive growth of multimedia big data in terms of both scale and variety over the last few years. Yet at the same time, security issues related to multimedia big data have arisen. An urgent demand has emerged for novel technologies that deal with copyright protection, multimedia forgery detection, and cybersecurity—especially for cyber-enabled multimedia applications. This special issue brings together research efforts in cybersecurity for cyber-enabled multimedia applications. [ABSTRACT FROM AUTHOR]

Cloud storage is an increasingly popular application of cloud computing, which can provide on-demand outsourcing data services for both organizations and individuals. However, users may not fully trust the cloud service providers (CSPs) in that it is difficult to determine whether the CSPs meet their legal expectations for data security. Therefore, it is critical to develop efficient auditing techniques to strengthen data owners’ trust and confidence in cloud storage. In this paper, we present a novel public auditing scheme for secure cloud storage based on dynamic hash table (DHT), which is a new two-dimensional data structure located at a third parity auditor (TPA) to record the data property information for dynamic auditing. Differing from the existing works, the proposed scheme migrates the authorized information from the CSP to the TPA, and thereby significantly reduces the computational cost and communication overhead. Meanwhile, exploiting the structural advantages of the DHT, our scheme can also achieve higher updating efficiency than the state-of-the-art schemes. In addition, we extend our scheme to support privacy preservation by combining the homomorphic authenticator based on the public key with the random masking generated by the TPA, and achieve batch auditing by employing the aggregate BLS signature technique. We formally prove the security of the proposed scheme, and evaluate the auditing performance by detailed experiments and comparisons with the existing ones. The results demonstrate that the proposed scheme can effectively achieve secure auditing for cloud storage, and outperforms the previous schemes in computation complexity, storage costs and communication overhead. [ABSTRACT FROM PUBLISHER]

Information hiding based on bitrate switching is a novel steganographic scheme for voice over IP, which can resist traditional steganalysis methods. However, the state-of-the-art method has not achieved its best embedding performance. Thus, in this letter, we present two adaptive bitrate modulating-based steganographic methods introducing Hamming matrix encoding (HME) strategy. The first one can conceal \lfloor \log 2(n+1)\rfloor bits of secret data into n speech frames with at most one bitrate switching by applying the HME strategy to each frame group, while the second one, compared with the state-of-the-art method, can embed (1+\lfloor \log 2(n+1)\rfloor)/2 bits of secret data into n speech frames without increasing the number of bitrate switches by only employing the HME strategy for the frame groups with bitrate switching. The theoretical analysis and experimental evaluation demonstrate that the proposed methods are feasible, and outperform the existing one on both covert bandwidth and embedding efficiency while achieving the comparably good steganographic transparency. [ABSTRACT FROM PUBLISHER]

Iris recognition has gained increasing popularity over the last few decades; however, the stand-off distance in a conventional iris recognition system is too short, which limits its application. In this paper, we propose a novel hardware–software hybrid method to increase the stand-off distance in an iris recognition system. When designing the system hardware, we use an optimized wavefront coding technique to extend the depth of field. To compensate for the blurring of the image caused by wavefront coding, on the software side, the proposed system uses a local patch-based super-resolution method to restore the blurred image to its clear version. The collaborative effect of the new hardware design and software post-processing showed great potential in our experiment. The experimental results showed that such improvement cannot be achieved by using a hardware-or software-only design. The proposed system can increase the capture volume of a conventional iris recognition system by three times and maintain the system’s high recognition rate. [ABSTRACT FROM PUBLISHER]

In 2014, Turkanovic et al. proposed a smart card-based authentication scheme for heterogeneous ad hoc wireless sensor network. This scheme is very efficient since it employs only hash function and XOR operation. However, we found that Turkanovic et al.’s scheme is vulnerable to impersonation attack with node capture, stolen smart card attack, sensor node spoofing attack, stolen verifier attack, and fails to ensure backward secrecy. We propose an efficient scheme to overcome all those weaknesses. Moreover, we also propose an advanced scheme, which provides perfect forward secrecy without much modification from the first proposed scheme. [ABSTRACT FROM PUBLISHER]