The Internet of Things (IoT) is also known as the Internet of everything. As an important part of the new generation of intelligent information technology, IoT has attracted the attention both of researchers and engineers all over the world. Considering the limited capacity of smart products, IoT mainly uses cloud computing to expand computing and storage resources. The massive data collected by the sensor are stored in the cloud storage server, also the cloud vulnerability will directly threaten the security and reliability of the IoT. In order to ensure data integrity and availability in the cloud and IoT storage system, users need to verify the integrity of remote data. However, existing remote data integrity verification schemes are mostly based on the RSA and BLS signature mechanisms. The RSA-based scheme has too much computational overhead. The BLS signature-based scheme needs to adopt a specific hash function, and the batch signature efficiency in the big data environment is low. Therefore, for the computational overhead and signature efficiency issues of these two signature mechanisms, we propose a scheme of data integrity verification based on a short signature algorithm (ZSS signature), which supports privacy protection and public auditing by introducing a trusted third party (TPA). The computational overhead is effectively reduced by reducing hash function overhead in the signature process. Under the assumption of CDH difficult problem, it can resist adaptive chosen-message attacks. Analysis shows that the scheme has a higher efficiency and safety.

With the rapid development of social networks, spam bots and other anomaly accounts’ malicious behavior has become a critical information security problem threatening the social network platform. In order to reduce this threat, the existing research mainly uses feature-based detection or propagation-based detection, and it applies machine learning or graph mining algorithms to identify anomaly accounts in social networks. However, with the development of technology, spam bots are becoming more advanced, and identifying bots is still an open challenge. This paper proposes a new semi-supervised graph embedding model based on a graph attention network for spam bot detection in social networks. This approach constructs a detection model by aggregating features and neighbor relationships, and learns a complex method to integrate the different neighborhood relationships between nodes to operate the directed social graph. The new model can identify spam bots by capturing user features and two different relationships among users in social networks. We compare our method with other methods on real-world social network datasets, and the experimental results show that our proposed model achieves a significant and consistent improvement.

Since the rapid development of the internet, the emergence of network intrusion has become the focus of studies for scholars and security enterprises. As an important device for detecting and analyzing malicious behaviors in networks, IDS (Intrusion Detection Systems) is widely deployed in enterprises, organizations and plays a very important role in cyberspace security. The massive log data produced by IDS not only contains information about intrusion behaviors but also contains potential intrusion patterns. Through normalizing, correlating, and modeling data, we can obtain the patterns of different intrusion scenarios. Based on the previous works in the area of alert correlation and analyzing, this paper proposed a framework named IACF (Intrusion Action Based Correlation Framework), which improved the process of alert aggregating, action extraction, and scenario discovery, and applied a novel method for extracting intrusion sessions based on temporal metrics. The proposed framework utilized a new grouping method for raw alerts based on the concept of intrinsic strong correlations, rather than the conventional time windows and hyper alerts. For discovering high stable correlations between actions, redundant actions and action link modes are removed from sessions by a pruning algorithm to reduce the impact of false positives, finally, a correlation graph is constructed by fusing the pruned sessions, based on the correlation graph, a prediction method for the future attack is proposed. The experiment result shows that the framework is efficient in alert correlation and intrusion scenario construction.

Vehicle ad-hoc network (VANET) is interconnected through message forwarding and exchanging among vehicle nodes. Due to its highly dynamic topology and its wireless and heterogeneous communication mode, VANET is more vulnerable to security threats from multiple parties. Compared to entity-based security authentication, it is essential to consider how to protect the security of the data itself. Existing studies have evaluated the reliability of interactive data through reputation quantification, but there are still some issues in the design of secure reputation management schemes, such as its low efficiency, poor security, and unreliable management. Aiming at the above-mentioned issues, in this paper we propose an effective VANET model with a secure reputation based on a blockchain, and it is called the double-layer blockchain-based reputation evaluation & management model (DBREMM). In the DBREMM, we design a reputation management model based on two parallel blockchains that work collaboratively, and these are called the event chain and reputation chain. A complete set of reputation evaluation schemes is presented. Our schemes can reduce observation errors and improve evaluation reliability during trust computation by using direct trust calculation based on the multi-factor Bayesian inference. Additionally, we propose an indirect trust calculation based on the historical accumulated reputation value with an attenuation factor, and a secure a reputation fusion scheme based on the number threshold with the fluctuation factor, which can reduce the possibility of attacks, such as collusive attacks and false information injection. Theoretical analysis and extensive simulation experiments reflect the DBREMM’s security algorithm effectiveness, accuracy, and ability to resist several attacks.

Trajectory k-anonymity is a prevalent technique for protecting trajectory privacy. However, the existing techniques for generating fake trajectories can be easily broken by an adversary because of the failure to capture the probabilistic features and geographic features of the trajectories. They also reduce data availability. Thus, this paper proposes a location recombination mechanism (LRM) for achieving trajectory k-anonymity privacy protection. First, we propose a metric that measures the location pair similarity between location pairs. Based on this metric, we select sampling locations and divide locations into different equivalent probability classes. Locations in one equivalent probability class have the same probability as one corresponding base location. Then, we also introduce two metrics that measure the probabilistic similarity and geographic similarity between locations. Based on these metrics, we design algorithms to generate fake trajectories. These algorithms can recombine locations sampled from each equivalent probability class into trajectories. All of these trajectories meet the privacy protection requirements for both base trajectories and sampling trajectories. Finally, we evaluate our scheme thoroughly with real-world data. The results show that our method can protect the privacy of base trajectories and sampling trajectories and achieve a better performance of service provider utility and data availability than other schemes.

Today, social networks are becoming increasingly popular and indispensable, where users usually have multiple accounts. It is of considerable significance to conduct user identity linkage across social networks. We can comprehensively depict diversified characteristics of user behaviors, accurately model user profiles, conduct recommendations across social networks, and track cross social network user behaviors by user identity linkage. Existing works mainly focus on a specific type of user profile, user-generated content, and structural information. They have problems of weak data expression ability and ignored potential relationships, resulting in unsatisfactory performances of user identity linkage. Recently, graph neural networks have achieved excellent results in graph embedding, graph representation, and graph classification. As a graph has strong relationship expression ability, we propose a user identity linkage method based on a heterogeneous graph attention network mechanism (UIL-HGAN). Firstly, we represent user profiles, user-generated content, structural information, and their features in a heterogeneous graph. Secondly, we use multiple attention layers to aggregate user information. Finally, we use a multi-layer perceptron to predict user identity linkage. We conduct experiments on two real-world datasets: OSCHINA-Gitee and Facebook-Twitter. The results validate the effectiveness and advancement of UIL-HGAN by comparing different feature combinations and methods.