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&quot;State machine replication (SMR) allows nodes to jointly maintain a consistent ledger, even when a part of nodes are Byzantine. To defend against and/or limit the impact of attacks launched by Byzantine nodes, there have been blocks that combine reputation mechanisms to SMR, where each node
has a reputation value based on its historical behaviours, and the
node’s voting power will be proportional to its reputation. Despite
the promising features of reputation-based SMR, existing studies
do not provide formal treatment on the reputation mechanism on
SMR protocols, including the types of behaviours affecting the
reputation, the security properties of the reputation mechanism,
and the extra security properties of SMR using reputation
mechanisms.
In this paper, we provide the first formal study on the
reputation-based SMR. We define the security properties of the
reputation mechanism w.r.t. these misbehaviours. Based on the
formalisation of the reputation mechanism, we formally define the
reputation-based SMR, and identify a new property reputationconsistency that is necessary for ensuring reputation-based SMR’s
safety. We then design a simple reputation mechanism that
achieves all security properties in our formal model. To demonstrate the practicality, we combine our reputation mechanism to
the Sync-HotStuff SMR protocol, yielding a simple and efficient
reputation-based SMR at the cost of only an extra ∆ in latency,
where ∆ is the maximum delay in synchronous networks.&quot;

IEEE NCA 2022

Reputation-based state machine replication

blockchain.

state machine replication

reputation

### Welcome to IEEE NCA 2022!

NCA 2022, the International Symposium on Network Computing and Applications, is a successful series of conferences that serves as a large international forum for presenting and sharing recent research results and technological developments in the fields of Network and Cloud Computing. NCA, which is sponsored by the IEEE Computer Society, reaches out to both researchers and practitioners, and to both academia and industry. The conference features keynotes, technical presentations, and workshops.

All papers presented at the main conference and the workshops will be submitted to IEEE Xplore for publication and indexing.

[More about NCA](https://www.nca-ieee.org/2022/index.html)

**Organization**

* Steering Committee Chair: Dimiter R. Avresky, *IRIANC, Boston/Munich, USA/Germany*
* General Chair: Michele Colajanni, *University of Bologna, Italy*
* Program Chair: Miguel Pardal, *INESC-ID, Lisboa, Portugal*
* Program Chair: Luca Ferretti, *University of Modena and Reggio Emilia, Italy*
* Financial Chair: Mauro Andreolini, *University of Modena and Reggio Emilia, Italy*

**The topics of interest include, but are not limited to:**

* Theory of Network Computing
* Autonomic Network Computing
* Content Delivery Network (CDN)
* High Speed Networks/Protocols and Middleware
* Routing Mechanisms
* Overlay Networks/Peer-to-Peer Systems
* System Area Networks (SAN)/Clusters
* Performance Modeling/Quality of Services (QoS) Issues
* Web Caching and Switching
* Dependable Wide, Local, and System Area Networks
* Network Security
* Intrusion-Tolerant Networked Systems
* Scalable and Dependable Servers and Data Centers
* Middleware for Dependable Network Computing
* Self* (Configuring, Healing, Optimizing, Protecting, Organizing, Aware)
* Platforms for Network Computing
* Network Protocols: Verification and Validation
* Autonomic Network Computing for Achieving Self* Properties and Applications Availability
* Seamless and Virtual Capabilities for Implementing Self* Properties
* Software Defined Networking (SDN): Principles and Implementation
* Designing Highly-Available and Secure SDN
* Network Functions Virtualization (NFV): Design and Optimization
* Network Cloud Computing
* Machine Learning Techniques for Cloud Resources Management
* Big Data in Clouds for IoT
* Future Internet and Communicating Objects
* Mobile Ad-Hoc Networks (MANET)
* Sensor Networks
* Fog/Edge Computing
* Energy-Efficient Computation and Communication
* Applications to Real and/or Complex Problems, Practical Experiences and Prototypes
* Programming Environments for Distributed Systems
* Blockchain
* Byzantine Fault Tolerance
* Web and Mobile Security
* Security of Networked Applications (including Automotive, Industrial and Cyberphysical Systems)


To access the IEEE NCA 2022 content, [please register here ](https://www.nca-ieee.org/2022/registration.html)

NCA 2022, the International Symposium on Network Computing and Applications, is a successful series of conferences that serves as a large international forum for presenting and sharing recent research results and technological developments in the fields of Network and Cloud Computing.

"State machine replication (SMR) allows nodes to jointly maintain a consistent ledger, even when a part of nodes are Byzantine. To defend against and/or limit the impact of attacks launched by Byzantine nodes, there have been blocks that combine reputation mechanisms to SMR, where each node
has a reputation value based on its historical behaviours, and the
node’s voting power will be proportional to its reputation. Despite
the promising features of reputation-based SMR, existing studies
do not provide formal treatment on the reputation mechanism on
SMR protocols, including the types of behaviours affecting the
reputation, the security properties of the reputation mechanism,
and the extra security properties of SMR using reputation
mechanisms.
In this paper, we provide the first formal study on the
reputation-based SMR. We define the security properties of the
reputation mechanism w.r.t. these misbehaviours. Based on the
formalisation of the reputation mechanism, we formally define the
reputation-based SMR, and identify a new property reputationconsistency that is necessary for ensuring reputation-based SMR’s
safety. We then design a simple reputation mechanism that
achieves all security properties in our formal model. To demonstrate the practicality, we combine our reputation mechanism to
the Sync-HotStuff SMR protocol, yielding a simple and efficient
reputation-based SMR at the cost of only an extra ∆ in latency,
where ∆ is the maximum delay in synchronous networks."

technical paper

"In this paper, we examine the inherent properties
of the Byzantine Reliable Broadcast (BRB) primitive as pertain
to the ability to provide causal ordering. We prove the following
results. First, we analyze Bracha’s BRB algorithm and show
that under the failure-free model, safety is guaranteed across
broadcasts. Second, we also prove that Bracha’s BRB algorithm
guarantees safety across broadcasts under the crash failure model
tolerating any number of crash failures. Third, we prove that
Bracha’s BRB algorithm cannot provide weak or strong safety
under the Byzantine failure model. Fourth, we prove that neither
the Imbs-Raynal BRB protocol nor any (2,*)-round BRB protocol
can provide causal order even if all processes are correct, and
they must incur additional latency to causally order messages at a
higher layer. The inherent causal ordering properties of Bracha’s
BRB can be of use under favourable circumstances in practical
applications, given the widespread adoption of the protocol."

Causal Ordering Properties of Byzantine Reliable Broadcast Primitives

Gossip-based dissemination protocols are important building blocks of large-scale distributed systems as they may impact both the systems' efficiency and fault tolerance. There exist many flavors of gossip dissemination protocols. IDA-Gossip is one of the gossip dissemination protocols proposed in the context of blockchains to efficiently disseminate large messages. It relies on multi-chunk gossip dissemination, erasure coding, and Merkle hash trees. However, despite its claimed efficiency, there is no in-depth analysis of this protocol to understand its behavior under different conditions (e.g., with injected faults). In this work, we evaluate the behavior of IDA-Gossip by relying on extensive experiments and simulations. Specifically, we evaluate IDA-Gossip both in terms of performance and resilience to faults by varying its configuration parameters and the number of faulty nodes, respectively. This study results in several takeaways. First, IDA-Gossip provides excellent dissemination latency compared to classic gossip. Second, it provides excellent coverage even with 40 percent of faulty nodes in the system. Finally, the use of erasure coding provides an important advantage to IDA-Gossip compared to classic multi-chunk gossip dissemination protocols.

In-depth analysis of the IDA-Gossip protocol

"Byzantine fault tolerant (BFT) consensus allows the construction of robust, distributed systems via the state-machine replication (SMR) approach. Still, after more than 40 years of research, limitations on performance and scalability for practical systems remain. A large corpus of existing work improves on consensus complexity, performance and introduces a multitude of optimization techniques. The state-of-the-art is complex. On the other hand, many protocols designed for practical deployments are built on strong, common assumptions about underlying communication and authentication primitives. To fulfill these assumptions, often, commodity tools and libraries are employed without further analysis and caution for negative interplay.
Instead of contributing to the existing complexity, we choose a different approach. In this work, we outline the feasibility and potential impact of the optimization of common building blocks of BFT-SMR systems. We systemize existing work in terms of common model assumptions and identify optimization potential.  Finally, we choose the building block of networking transport as a representative example and analyze its optimization space, both in context of general BFT-SMR systems and a case study of the HotStuff protocol. We describe behavior, challenges, and desired configuration of network transports for use in byzantine agreement, and identify lossy links as the main catalyst for significant performance differences between protocols and configurations."

BFT-Blocks: The Case for Analyzing Networking in Byzantine Fault Tolerant Consensus

Most of today's online services (e.g. social networks, search engines, marketplace places) are centralized, which most users recognize as unsatisfactory for various reasons (e.g. centralized governance, censorship, loss of control over personal data). Blockchain technologies promise a new Web revolution (Web 3.0) through the decentralization of online services. However, one of the fundamental limitations for this revolution to happen at a planetary scale is the poor performance of today's permissionless blockchains. In this paper, we propose ALDER, a generic construction that multiplexes off-the-shelf permissionless blockchain protocols to address the performance bottleneck due to store-validate-forward block dissemination techniques in blockchain protocols.
We apply ALDER to two representative blockchains, namely Algorand (Proof-of-Stake) and Bitcoin (Proof-of-Work), to illustrate the benefits it brings to blockchain performance. Our evaluations show that ALDER can drastically improve the throughput of blockchains when bottlenecks exist. 

ALDER: Unlocking blockchain performance by multiplexing consensus protocols

Causal ordering of broadcasts is a widely used
requirement in collaborative distributed software systems. We
consider Byzantine-tolerant causal ordering of broadcasts in a
replicated data store implemented over an incomplete graph
network topology, wherein messages of the broadcast are sent
via flooding. We propose two protocols to achieve this. The
incomplete graph topology also occurs naturally in wireless
networks and in overlay peer-to-peer networks. We identify four
properties – safety, liveness, no impersonation, and no avatars
– that a Byzantine-tolerant causal broadcast algorithm for a
replicated data store over an incomplete graph must satisfy. We
also reformulate the traditional properties – validity, integrity,
self-delivery, and reliability (or termination) – specified for a
complete graph in the literature for a replicated data store system
over an incomplete graph topology. We then analyze whether
Byzantine processes can mount attacks on these properties in our
two protocols. We show results for the classical communication
model and the local broadcast model.

Byzantine Fault-Tolerant Causal Broadcast on Incomplete Graphs

Nowadays, tourists turn to digital platforms to discover new places to explore. CROSS City is a smart tourism mobile application that enhances the user experience of tourists visiting points of interest in a route by rewarding them in the end, if they actually visited all locations. From a technical standpoint, the user location is certified resorting to strategies that take advantage of both the diversity of the existing Wi-Fi network infrastructure throughout the city, as well as the presence of other users at the same site using Bluetooth. This work developed a new, peer-to-peer location certification strategy and added gamification elements to encourage users to keep the wireless radios turned on and use the app more. This work was evaluated both in laboratory experiments and with users in a real-world scenario which demonstrated that the new Bluetooth peer-based strategy is both feasible and resistant to collusion attacks.

Bluetooth Peer-to-Peer Location Certification with a Gamified Mobile Application

In this work we present a set of issues affecting the research topic of cybersecurity on in-vehicle networks and we publicly address them by comparing three selected works against the same attack scenarios available in public datasets.

Comparison of Machine Learning-based anomaly detectors for Controller Area Network

Industrial plants are adopting an increasing number of digital interconnected technologies that are enriched by several software applications. The IT/OT convergence offers several benefits in terms of efficiency and flexibility but it opens as many issues in terms of cyber vulnerabilities because industrial plants were not designed to be open to Internet. The frequency of successful cyber attacks shows that typical security solutions are inadequate to the novel complexity of industrial contexts. This novel scenario requires original approaches differing from tradi- tional multi-layer networking solutions that are applicable just to rigid and stable infrastructures. We explore the applicability of Zero Trust Architecture (ZTA) principles to the industrial context by designing, implementing and testing an integrated defensive solution. The results obtained through a working prototype show that it is possible to implement a Zero Trust identity-centric approach in an industrial context to increase the security and flexibility of the system while providing complete visibility over the entire network. The proposed approach can be used to strengthen legacy industrial systems that were designed for offline use, and to allow the adoption of innovative technologies that minimize the cyber risk for the overall infrastructure.

A Zero Trust approach for the cybersecurity of Industrial Control Systems

A new CRT-based secret-sharing scheme with perfect information-theoretic (PIT) security and multiplicative homomorphism is presented. Given some background and references to related works.

Multiplicative Partially Homomorphic CRT Secret Sharing

This paper demonstrates and proves that the coordination of actions in a distributed swarm can be enhanced by using quantum entanglement. In particular, we focus on
• Global and local simultaneous random walks, using entangled qubits that collapse into the same (or opposite) direction, either random direction or totally controlled simultaneous movements.
• Identifying eavesdropping from malicious eavesdroppers aimed at disturbing the simultaneous random walks by using entangled qubits that were sent at random or with predefined bases

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Causal Ordering Properties of Byzantine Reliable Broadcast Primitives

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