Mobile devices have penetrated our daily life, and so have the fast chargers. However, while improving users' charging efficiency, fast chargers may pose severe security threats. In this work, we present a novel side-channel attack called ChargerWhisper, which exploits the acoustic signals generated by fast chargers to infer users' private information in an on-charging mobile device. In particular, when users perform different activities on the charging device, the fast charger will supply distinct amounts of power outputs to the mobile device. By conducting a deep investigation of the fast charger circuits, we find that the electronic components, i.e., inductors, capacitors, and transformers, vibrate at certain frequencies and generate high-frequency inaudible sounds. Meanwhile, the leaked sound frequencies are highly correlated with electric intensity flowing through these electronic components (charger's output power). To demonstrate the acoustic side-channel attack leveraging fast chargers, we present two specific exploitation scenarios: a website fingerprinting attack to identify users' on-browsing websites, and a PIN inference attack to infers the device's unlock PIN. Extensive evaluations are performed on off-the-shelf devices. The results show that both attacks are robust under diverse usage settings and achieve good performance in inferring users' privacy information. These findings highlight the essential need to address unnoticed privacy leakage risks associated with fast chargers.

Large language models (LLMs) demonstrate remarkable capabilities in understanding complex tasks and have achieved commendable performance in graph-related tasks, such as node classification, link prediction, and subgraph classification.These tasks primarily depend on the local reasoning capabilities of the graph structure.However, research has yet to address the graph partitioning task that requires global perception abilities.Our preliminary findings reveal that vanilla LLMs can only handle graph partitioning on extremely small-scale graphs.To overcome this limitation, we propose a three-phase pipeline to empower LLMs for large-scale graph partitioning: coarsening, reasoning, and refining.The coarsening phase reduces graph complexity.The reasoning phase captures both global and local patterns to generate a coarse partition.The refining phase ensures topological consistency by projecting the coarse-grained partitioning results back to the original graph structure.Extensive experiments demonstrate that our framework enables LLMs to perform graph partitioning across varying graph scales, validating both the effectiveness of LLMs for partitioning tasks and the practical utility of our proposed methodology.

With an increasing amount of data produced by pervasive and ubiquitous smart devices, many Internet of Things (IoT) applications adopt the cloud platform to store and process data. To protect data security and privacy, attribute-based encryption (ABE) has been widely used in cloud-assisted IoT systems. However, most ABE schemes usually require a central authority to distribute decryption keys for all users, which may raise security and efficiency concerns; in addition, the exposure of decryption keys would severely damage the data privacy. In this article, we introduce a novel notion of decentralized attribute-based puncturable encryption (DABPE). DABPE allows data owner to generate public and secret keys by himself, without relying on any central authority. When outsourcing data to the cloud, the data owner can encrypt data with an access policy; moreover, the data owner could issue particular keys for different data users and only those users whose keys satisfy the access policy can access the data. To achieve a flexible forward security, the data owner and data user can update their keys with some tags such that the data specified by the tags would not be revealed even if the keys are disclosed. We design a concrete DABPE scheme and prove its security in the standard model, and also conduct extensive experiments to show the efficiency of the proposed scheme.

RDF (Resource Description Framework) is a model widely used to construct knowledge bases, while SPARQL (SPARQL Protocol and RDF Query Language) is the standardized structured query language to manipulate RDF data. Recently, many data providers have published their RDF datasets in their own autonomous sites and provided SPARQL query interfaces, calledRDF sources. In order to integrate multiple RDF sources, researchers put forward the federated RDF system to support the federated SPARQL queries. However, existing studies can only support efficient basic queries but not top-k queries. Toward this end, we propose a cost-driven top-k queries optimization approach in federated RDF systems, which can support both top-k queries for single variable ordering and expression ordering. Firstly, we propose an optimized query decomposition method to decompose the federated query into multiple subqueries. Secondly, while considering the top-k operator, we propose a cost model to evaluate the query cost and join cost of subqueries. The optimal query plan can be obtained by the costed-based query plan generation algorithm. Finally, combined with the characteristics of top-k queries, an incremental query plan execution strategy is developed to minimize the total query cost. Experimental results show that the proposed method is effective, efficient and scalable.