A framework for analyzing RFID distance bounding protocols

Many distance bounding protocols appropriate for the RFID technology have been proposed recently. Unfortunately, they are commonly designed without any formal approach, which leads to inaccurate analyzes and unfair comparisons. Motivated by this need, we introduce a unied framework that aims to improve analysis and design of distance bounding protocols. Our framework includes a thorough terminology about the frauds, adversary, and prover, thus disambiguating many misleading terms. It also explores the adversary's capabilities and strategies, and addresses the impact of the prover's ability to tamper with his device. It thus introduces some new concepts in the distance bounding domain as the black-box and white-box models, and the relation between the frauds with respect to these models. The relevancy and impact of the framework is nally demonstrated on a study case: Munilla-Peinado distance bounding protocol

Formal Computational Unlinkability Proofs of RFID Protocols

We set up a framework for the formal proofs of RFID protocols in the computational model. We rely on the so-called computationally complete symbolic attacker model. Our contributions are: i) To design (and prove sound) axioms reflecting the properties of hash functions (Collision-Resistance, PRF); ii) To formalize computational unlinkability in the model; iii) To illustrate the method, providing the first formal proofs of unlinkability of RFID protocols, in the computational model

InversOS: Efficient Control-Flow Protection for AArch64 Applications with Privilege Inversion

With the increasing popularity of AArch64 processors in general-purpose computing, securing software running on AArch64 systems against control-flow hijacking attacks has become a critical part toward secure computation. Shadow stacks keep shadow copies of function return addresses and, when protected from illegal modifications and coupled with forward-edge control-flow integrity, form an effective and proven defense against such attacks. However, AArch64 lacks native support for write-protected shadow stacks, while software alternatives either incur prohibitive performance overhead or provide weak security guarantees. We present InversOS, the first hardware-assisted write-protected shadow stacks for AArch64 user-space applications, utilizing commonly available features of AArch64 to achieve efficient intra-address space isolation (called Privilege Inversion) required to protect shadow stacks. Privilege Inversion adopts unconventional design choices that run protected applications in the kernel mode and mark operating system (OS) kernel memory as user-accessible; InversOS therefore uses a novel combination of OS kernel modifications, compiler transformations, and another AArch64 feature to ensure the safety of doing so and to support legacy applications. We show that InversOS is secure by design, effective against various control-flow hijacking attacks, and performant on selected benchmarks and applications (incurring overhead of 7.0% on LMBench, 7.1% on SPEC CPU 2017, and 3.0% on Nginx web server).Comment: 18 pages, 9 figures, 4 table

Efficient and expressive keyword search over encrypted data in the cloud

National Research Foundation (NRF) Singapor

Adaptive conflict-free optimization of rule sets for network security packet filtering devices

Packet filtering and processing rules management in firewalls and security gateways has become commonplace in increasingly complex networks. On one side there is a need to maintain the logic of high level policies, which requires administrators to implement and update a large amount of filtering rules while keeping them conflict-free, that is, avoiding security inconsistencies. On the other side, traffic adaptive optimization of large rule lists is useful for general purpose computers used as filtering devices, without specific designed hardware, to face growing link speeds and to harden filtering devices against DoS and DDoS attacks. Our work joins the two issues in an innovative way and defines a traffic adaptive algorithm to find conflict-free optimized rule sets, by relying on information gathered with traffic logs. The proposed approach suits current technology architectures and exploits available features, like traffic log databases, to minimize the impact of ACO development on the packet filtering devices. We demonstrate the benefit entailed by the proposed algorithm through measurements on a test bed made up of real-life, commercial packet filtering devices