In this paper, we propose a new secure data integrity verification scheme for mobile edge computing (MEC), named IntactEdge, which provides an efficient method for end users in MEC to verify that the edge servers correctly maintain their stored data. Particularly, IntactEdge is designed using lightweight cryptographic mechanisms, such as message authentication codes and hash functions, to ensure efficiency in generating and verifying data integrity proofs. Batch verification is also supported to further enhance computational efficiency for end users during integrity checks. In addition, IntactEdge offers the desirable feature of multi-replica secure storage, allowing user data to be distributed across multiple edge servers to enhance data availability. To prevent edge nodes from exploiting data replicas stored on other nodes to falsely satisfy integrity verification requests, IntactEdge generates distinct data replicas for different edge nodes, while still enabling each replica to support proof generation using the same authentication tag. Finally, we demonstrate that IntactEdge is secure against potential data integrity attacks on edge servers and highly efficient in both tag generation and integrity verification.

Split federated learning (SFL) is a recently proposed distributed collaborative learning architecture that integrates federated learning (FL) with split learning (SL), offering an ingenious solution for safeguarding privacy in resource-limited environments. Despite the compelling potential of SFL and its appealing attributes, its robustness remains uncharted territory. In this paper, we investigate the security and robustness of SFL, with a specific focus on its susceptibility to malicious client-driven poisoning attacks. Specifically, we study the weaknesses of SFL against the well-known poisoning attacks designed for FL, like dataset poisoning, weight poisoning, and label poisoning. We also introduce a novel type of poisoning attacks tailored for SFL, named smash poisoning, and evaluate the robustness against smash poisoning attacks and advanced hybrid attacks (DatasetSmash, LabelSmash, and WeightSmash) that amalgamate smash poisoning with the other three methods for FL. By simulating these attacks across diverse domains over four datasets, we find that most of these attacks (including weight, WeightSmash, and LabelSmash poisoning) can disrupt the converged models with straightforward poisoning actions or have persistent negative influence on the model accuracy even after the termination of the attacks. Furthermore, our findings reveal that the robustness of SFL can be augmented by strategically adjusting the system parameters, such as client quantity, bottleneck size or split type. Finally, we verify the effectiveness of the typical defense mechanisms of poisoning attacks intended for FL and design a new defense strategy that filters out malicious smashed data to improve the robustness of SFL. We observe that the adoption of properly chosen defense mechanisms is beneficial in decreasing the security risks of SFL, but entirely eliminating the impacts of poisoning attacks in SFL is still challenging.

Secure data deletion enables data owners to have full control over the erasure of their data stored on local or cloud data centers, and it is essential for preventing data leakage, especially in cloud storage. However, traditional data deletion methods based on unlinking, overwriting, and cryptographic key management are either ineffective in cloud storage or rely on impractical assumptions. In this paper, we introduce SevDel, a secure and verifiable data deletion scheme that utilizes zero-knowledge proofs to achieve verification of the encryption of outsourced data without retrieving the ciphertexts. Meanwhile, the deletion of encryption keys is guaranteed based on Intel SGX. SevDel implements secure interfaces for performing data encryption and decryption in secure cloud storage. It also utilizes smart contracts to enforce the operations of the cloud service provider, ensuring compliance with service level agreements with data owners and imposing penalties on the service provider for disclosing cloud data on its servers. Evaluation using real-world workloads demonstrates that SevDel efficiently achieves data deletion verification and maintains high bandwidth savings.

In this paper, we propose a novel verifiable and privacy-preserving ad exchange scheme (VPAE) for smart targeted advertising that enables an ad exchange to deliver promotional advertisements to Internet users according to their specific interests, traits, and preferences. VPAE achieves the distinguished feature to preserve private information of both user profiles and advertisers, while allowing users to verify why they receive specific advertisements for adverting transparency. By utilizing homomorphic proxy re-encryption, VPAE addresses the challenge that the ad exchange has the ability to select advertisements for users, but they cannot know more than what they should. Meanwhile, VPAE integrates polynomial evaluations to achieve that the user is capable of verifying why she receives the advertisement, without learning any information of other advertisements that she does not receive. The privacy of both user profiles and advertisers are protected without sacrificing the efficiency of profile matching. We show the computational and communication overhead of VPAE through extensive analysis to demonstrate practicality and resource needs in implementation.1

E-petition has played an important role in health and politics that collects public opinions and requests a superior or an authority to take actions towards a health or political problem. However, this activity exposes the privacy of the signers who participate to express opinions. In this paper, we propose a privacy-preserving fine-grained e-petition system that supports attribute-based identity verification for signers, while protecting their privacy. By considering the target groups of signers in a specific health or political petition, an attribute policy is defined to ensure that only the signers with the attributes that satisfy the attribute policy can sign the petition. The fine-grained petition is better than the traditional e-petitions because it can improve the trustworthiness of the petition results via proactive signer selection. Moreover, the new petition system protects the identities of the signers by using the non-interactive zero-knowledge proof system, such that the signers are anonymous in signing petitions. In addition, the proposed petition system supports the tracing of double-signing, a cheating behavior that an anonymous signer can submit more than one signature in a petition without being detected. Finally, we prove that the proposed petition system achieves the desirable security properties, including anonymity, unforgeability, and traceability, and demonstrate that the system is efficient to be implemented on the mobile devices.

In this paper, we investigate the efficiency of network access control with the co-existence of multiple network operators and propose an efficient and secure network access control architecture (ESNAC) that offers fast identity authentication and access authorization in space-air-ground integrated networks. The major challenge lies in enabling multiple independent network operators to authorize and authenticate mobile users for network access in a secure and efficient way, even they are not mutually trusted. To address this challenge, we introduce an aggregate anonymous credential mechanism to enable a mobile user to present network access authorization of a group of network operators based on the consolidated anonymous credential that is aggregated from the partial anonymous credentials of the network operators. In addition, the efficient authentication of packet delivery is provided based on a sequential aggregate signature that allows each network operator to sign network packets for authentication and sequentially aggregate signatures for communication efficiency. Finally, we discuss the desired security properties of ESNAC and demonstrate its computational and communication efficiency by comparing with the conventional scheme without aggregation.