Hardware security has recently re-surfaced as a first-order concern to the confidentiality protections of computing systems. Meltdown and Spectre introduced a new class of microarchitectural exploits ...which leverage transient state as an attack vector, revealing fundamental security vulnerabilities of speculative execution in high-performance processors. These attacks profit from the fact that, during speculative execution, programs may execute instructions outside their legal control flows. This is used to gain access to restricted data, which is then exfiltrated through a covert channel. This paper proposes SpecShield, a family of microarchitectural mitigation techniques for shielding speculative data from covert channels used in transient execution attacks. Unlike prior work that has focused on closing individual covert channels used to leak sensitive information, SpecShield prevents the use of speculative data by downstream instructions until doing so is determined to be safe, thus isolating it from any covert channel. The most secure version of SpecShield eliminates transient execution attacks at a cost of 21% average performance degradation. A more aggressive version of SpecShield, which prevents the propagation of speculative data to known or probable covert channels provides only slightly relaxed security guarantees with an average of 10% performance impact.
Parallel and Asynchronous Smart Contract Execution Liu, Jian; Li, Peilun; Cheng, Raymond ...
IEEE transactions on parallel and distributed systems,
2022-May-1, 2022-5-1, Volume:
33, Issue:
5
Journal Article
Peer reviewed
Open access
Today's blockchains suffer from low throughput and high latency, which impedes their widespread adoption of more complex applications like smart contracts. In this article, we propose a novel ...paradigm for smart contract execution. It distinguishes between consensus nodes and execution nodes: different groups of execution nodes can execute transactions in parallel; meanwhile, consensus nodes can asynchronously order transactions and process execution results. Moreover, it requires no coordination among execution nodes and can effectively prevent livelocks. We show two ways of applying this paradigm to blockchains. First, we show how we can make Ethereum support parallel and asynchronous contract execution without hard-forks . Then, we propose a new public, permissionless blockchain. Our benchmark shows that, with a fast consensus layer, it can provide a high throughput even for complex transactions like Cryptokitties gene mixing. It can also protect simple transactions from being starved by complex transactions.
Federated Learning (FL) allows multiple clients to collaboratively train machine learning models while preserving the model privacy of the clients. However, when generating a global model during the ...aggregation process, a malicious FL server could derive clients’ local model weights. Such a threat cannot be completely eliminated, even if model aggregation is performed in the Trusted Execution Environment of the server, due to memory access pattern attacks. To tackle this challenge, our paper focuses on the top-k model aggregation algorithm in FL and introduces a space efficient and oblivious sparsified model aggregation algorithm named Sort-Then-Insert (STI), which removes the dependency of the memory access pattern on the model input, thus protecting the confidentiality of clients’ models. Compared with Path ORAM, STI is over 100 times faster, and compared with the state-of-the-art solution for the same problem, Olive, our theoretical analysis and experiments demonstrate that STI can achieve comparable performance overhead (O(nklog2(nk))+O(dlog2(d)) for STI vs. O((nk+d)log2(nk+d)) for Olive) and reduced space overhead (max(O(nk),O(d)) for STI vs. O(nk+d) for Olive).
•A top-k model aggregation algorithm for FL achieving memory access obliviousness.•Similar time complexity and reduced space complexity, compared with existing works.•Evaluated through experiments using two sorting networks and different parameters.
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In the design of robot skills, the focus generally lies on increasing the flexibility and reliability of the robot execution process; however, typical skill representations are not designed for ...analysing execution failures if they occur or for explicitly learning from failures. In this paper, we describe a learning-based hybrid representation for skill parameterisation called an execution model, which considers execution failures to be a natural part of the execution process. We then (i) demonstrate how execution contexts can be included in execution models, (ii) introduce a technique for generalising models between object categories by combining generalisation attempts performed by a robot with knowledge about object similarities represented in an ontology, and (iii) describe a procedure that uses an execution model for identifying a likely hypothesis of a parameterisation failure. The feasibility of the proposed methods is evaluated in multiple experiments performed with a physical robot in the context of handle grasping, object grasping, and object pulling. The experimental results suggest that execution models contribute towards avoiding execution failures, but also represent a first step towards more introspective robots that are able to analyse some of their execution failures in an explicit manner.
•Design of execution models, a hybrid representation for skill parameterisation that makes it possible to analyse execution failures and learn from them.•Description of a procedure for learning how to generalise execution models between object categories.•Development of algorithms for identifying a likely cause of a parameterisation failure and proposing a parameter correction.
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Divorce or the breaking up of a marriage between husband and wife through a court decision has legal consequences for both parties' rights and obligations, including children. In Indonesia, cases ...that are often problematic in divorce cases are the failure to achieve the execution of decisions, especially in the context of the right to support the wife and children and child custody. However, in this paper, the author is interested in examining more deeply the obstacles that occur in implementing the execution of child custody decisions that are seen from several legal perspectives, including the compilation of Islamic law, the Marriage Law, the Child Protection Law, and the regulation of the execution process of decisions. in Herziene Inlandsch Reglement (HIR). The legal research method used is Normative Law with a statutory approach or called the statute approach. This paper also uses secondary legal data sources, such as: scientific journals, books, related laws and regulations. The purpose of this paper is to provide solutions related to the obstacles that occur in the implementation of decisions on the execution of child custody rights, which until now often occur and still provide polemics both in society and within the scope of religious and state courts.
To fill the reference model gaps in the Manufacturing Execution System (MES) platform software field, the definitions for platform software and reference model are put forward, and a reference model ...for MES platform conforming to Industrie 4.0 specification is proposed. The MES platform was characterized by the reference model from three dimensions of problem space, lifetime and infrastructure, in which, each dimension was represented by a view that consists of a number of viewpoints. In building the reference model, the viewpoints selection processes were discussed based on the current standards in each area corresponding to each dimension, and then a concept of reference model building block was defined. Furthermore, in order to explain how the reference model can be applied in use, some examples were performed for a representative application scenario in Industrie 4.0 and illustrating the reference model in combination with the application of specific technologies. A conclusion and expectation for the reference model research were summarized in the end of the paper.
The culmination of a civil case in court is marked by the crucial step of decision implementation, commonly known as execution. Execution can only proceed when the decision attains permanent legal ...force ('inkracht van gewijsde'). While the losing party may voluntarily execute the decision, failure to fulfill stipulated obligations empowers the winning party, the plaintiff, to seek forced execution. Despite the irrevocable legal status of a decision, as signified by its permanent legal force, Indonesian civil procedural law affords opportunities for litigants and third parties to reassess such decisions. This reassessment is facilitated through challenges or rebuttals, as outlined in Article 195 paragraph (6) HIR, Article 206 paragraph (6) Rbg, Article 378 RV, Article 279 RV, and is guided by the Ius Curia Novit principle, as affirmed in Article 10 of Law Number 48 of 2009 concerning Power Justice. Utilizing a normative juridical approach, this study relies on secondary data to explore the nuances of execution and post-decision challenges, drawing on primary legal materials, secondary legal materials, and tertiary legal materials.
Processing large scientific applications generates a huge amount of data, which makes running experiments in the cloud computing environment very expensive and energy-consuming. To find an optimal ...solution to the workflow scheduling problem, several approaches have been presented for scheduling workflow on cloud resources. However, more efficient approaches are needed to improve cloud service delivery. In this paper, an energy-efficient virtual machine mapping algorithm (EViMA) is proposed to improve resource management in the cloud computing environment to achieve effective scheduling that reduces cloud data center energy consumption, execution makespan, and execution cost. This ensures that the requirements of cloud users are met, and improves the quality of services offered by cloud providers. Our proposed mechanism considers the heterogeneity of scheduling from both cloud users’ and workflow applications’ perspectives. Through simulation experiments on real workflow datasets, the proposed EViMA can provide better solutions for both cloud users and cloud providers by reducing energy consumption, execution makespan, and execution cost better than the state-of-the-art.
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We introduce a method of reversing the execution of imperative concurrent programs. Given an irreversible program, we describe the process of producing two versions. The first performs forward ...execution and saves information necessary for reversal. The second uses this saved information to simulate reversal. We propose using identifiers to capture statement execution order, and to use this to correctly undo data races via backtracking reversibility. We prove this reversibility to be correct, showing that the initial program state is restored and that all saved information is used (garbage-clean).
•Reversal of a concurrent imperative programming language that stores minimal data to undo irreversible steps•Identifiers assigned to statements as they execute that determines reverse control flow and ensures correct reversibility•Proof of correctness confirms the method of reversal restores program states and does not produce garbage•Reversibility illustrated on an implementation of a parallel sorting algorithm, with forward and reverse execution described
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Seamless application execution is vital for the usability of various delay-sensitive mobile cloud applications. However, the resource-intensive migration process and intrinsic limitations of the ...wireless medium impede the realization of seamless execution in mobile cloud computing (MCC) environment. This work is the first comprehensive survey that studies the state-of-the-art cloud-based mobile application execution frameworks (CMAEFs) in perspective of seamless application execution in MCC and investigates the frameworks suitability for the seamless execution. The seamless execution enabling approaches for the CMAEFs are identified and classified based on the implementation locations. We also investigate the seamless application execution enabling approaches to identify advantages and disadvantages of employing such approaches for attaining the seamless application execution in MCC. The existing frameworks are compared based on the significant parameters derived from the taxonomy of the seamless application execution enabling approaches. The principles for enabling the seamless application execution within the MCC are also highlighted. Finally, open research challenges in realizing the seamless application execution are discussed.
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