605 research outputs found
Isolation Without Taxation: {N}ear-Zero-Cost Transitions for {WebAssembly} and {SFI}
Software sandboxing or software-based fault isolation (SFI) is a lightweight
approach to building secure systems out of untrusted components. Mozilla, for
example, uses SFI to harden the Firefox browser by sandboxing third-party
libraries, and companies like Fastly and Cloudflare use SFI to safely co-locate
untrusted tenants on their edge clouds. While there have been significant
efforts to optimize and verify SFI enforcement, context switching in SFI
systems remains largely unexplored: almost all SFI systems use
\emph{heavyweight transitions} that are not only error-prone but incur
significant performance overhead from saving, clearing, and restoring registers
when context switching. We identify a set of \emph{zero-cost conditions} that
characterize when sandboxed code has sufficient structured to guarantee
security via lightweight \emph{zero-cost} transitions (simple function calls).
We modify the Lucet Wasm compiler and its runtime to use zero-cost transitions,
eliminating the undue performance tax on systems that rely on Lucet for
sandboxing (e.g., we speed up image and font rendering in Firefox by up to
29.7\% and 10\% respectively). To remove the Lucet compiler and its correct
implementation of the Wasm specification from the trusted computing base, we
(1) develop a \emph{static binary verifier}, VeriZero, which (in seconds)
checks that binaries produced by Lucet satisfy our zero-cost conditions, and
(2) prove the soundness of VeriZero by developing a logical relation that
captures when a compiled Wasm function is semantically well-behaved with
respect to our zero-cost conditions. Finally, we show that our model is useful
beyond Wasm by describing a new, purpose-built SFI system, SegmentZero32, that
uses x86 segmentation and LLVM with mostly off-the-shelf passes to enforce our
zero-cost conditions; our prototype performs on-par with the state-of-the-art
Native Client SFI system
Efficient layering for high speed communication: the MPI over Fast Messages (FM) experience
We describe our experience of designing, implementing, and evaluating two generations of high performance communication libraries, Fast Messages (FM) for Myrinet. In FM 1, we designed a simple interface and provided guarantees of reliable and in-order delivery, and flow control. While this was a significant improvement over previous systems, it was not enough. Layering MPI atop FM 1 showed that only about 35 % of the FM 1 bandwidth could be delivered to higher level communication APIs. Our second generation communication layer, FM 2, addresses the identified problems, providing gather-scatter, interlayer scheduling, receiver flow control, as well as some convenient API features which simplify programming. FM 2 can deliver 55–95 % to higher level APIs such as MPI. This is especially impressive as the absolute bandwidths delivered have increased over fourfold to 90 MB/s. We describe general issues encountered in matching two communication layers, and our solutions as embodied in FM 2
A Survey on Wireless Sensor Network Security
Wireless sensor networks (WSNs) have recently attracted a lot of interest in
the research community due their wide range of applications. Due to distributed
nature of these networks and their deployment in remote areas, these networks
are vulnerable to numerous security threats that can adversely affect their
proper functioning. This problem is more critical if the network is deployed
for some mission-critical applications such as in a tactical battlefield.
Random failure of nodes is also very likely in real-life deployment scenarios.
Due to resource constraints in the sensor nodes, traditional security
mechanisms with large overhead of computation and communication are infeasible
in WSNs. Security in sensor networks is, therefore, a particularly challenging
task. This paper discusses the current state of the art in security mechanisms
for WSNs. Various types of attacks are discussed and their countermeasures
presented. A brief discussion on the future direction of research in WSN
security is also included.Comment: 24 pages, 4 figures, 2 table
Multi-Factor Authentication: A Survey
Today, digitalization decisively penetrates all the sides of the modern society. One of the key enablers to maintain this process secure is authentication. It covers many different areas of a hyper-connected world, including online payments, communications, access right management, etc. This work sheds light on the evolution of authentication systems towards Multi-Factor Authentication (MFA) starting from Single-Factor Authentication (SFA) and through Two-Factor Authentication (2FA). Particularly, MFA is expected to be utilized for human-to-everything interactions by enabling fast, user-friendly, and reliable authentication when accessing a service. This paper surveys the already available and emerging sensors (factor providers) that allow for authenticating a user with the system directly or by involving the cloud. The corresponding challenges from the user as well as the service provider perspective are also reviewed. The MFA system based on reversed Lagrange polynomial within Shamir’s Secret Sharing (SSS) scheme is further proposed to enable more flexible authentication. This solution covers the cases of authenticating the user even if some of the factors are mismatched or absent. Our framework allows for qualifying the missing factors by authenticating the user without disclosing sensitive biometric data to the verification entity. Finally, a vision of the future trends in MFA is discussed.Peer reviewe
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