Web3.0, often cited to drastically shape our lives, is ubiquitous. However, few literatures have discussed the crucial differentiators that separate Web3.0 from the era we are currently living in. Via a thorough analysis of the recent blockchain infrastructure evolution, we capture a key invariant featuring the evolution, based on which we provide the first academic definition for Web3.0. Our definition is not the only way of understanding Web3.0, yet, it captures the fundamental and defining trait of Web3.0, and meanwhile it is has two desirable properties. Under this definition, we articulate three key infrastructural enablers for Web3.0: individual blockchains, federated or centralized platforms capable of publishing verifiable states, and an interoperability platform to hyperconnect those state publishers. While innovations in all categories are necessary to fully enable Web3.0, in this paper, we present a design for the third enabler, namely HyperService, that delivers interoperability and programmability across heterogeneous blockchains and state publishers. HyperService is powered by two innovative designs: a developer-facing programming framework that allows developers to build cross-chain applications in a unified programming model; and a secure blockchain-facing cryptography protocol that provably realizes those applications on blockchains. We implement a prototype of HyperService in 62,000 lines of code to demonstrate its practicality, usability, and scalability.

Volumetric attacks, which overwhelm the bandwidth of a destination, are among the most common distributed denial-of-service (DDoS) attacks today. Despite considerable effort made by both research and industry, our recent interviews with over 100 potential DDoS victims in over 10 industry segments indicate that today's DDoS prevention is far from perfect. On one hand, few academical proposals have ever been deployed in the Internet; on the other hand, solutions offered by existing DDoS prevention vendors are not silver bullet to defend against the entire attack spectrum. Guided by such large-scale study of today's DDoS defense, in this paper, we present MiddlePolice, the first readily deployable and proactive DDoS prevention mechanism. We carefully architect MiddlePolice such that it requires no changes from both the Internet core and the network stack of clients, yielding instant deployability in the current Internet architecture. Further, relying on our novel capability feedback mechanism, MiddlePolice is able to enforce destination-driven traffic control so that it guarantees to deliver victim-desired traffic regardless of the attacker strategies. We implement a prototype of MiddlePolice and demonstrate its feasibility via extensive evaluations in the Internet, hardware testbed, and large-scale simulations.

The state-of-the-art digital signatures incur undesirable delays, hence are impractical for time-stringent Industrial Control Systems (ICSs). The recent revision to IEC 62351–6 standard stepped back from digital signatures in favor of symmetric key based solutions, thereby sacrificing key properties, e.g., scaling well for multiple destinations, easy key distribution and management, public verifiability, and non-repudiation. Inspired by the Online/Offline signatures, this paper presents a new digital signature model to provide the key properties of digital signatures within the delay requirements, hinting that this step back can be avoided. The Online/Offline signatures concept divides the signature generation into two phases; offline (before the message is given), online (using the outputs of the former for faster signing after the message is given). The conventional solutions following this concept potentially reduce the delay, yet do not meet IEC 61850 delay requirements as they still involve expensive operations in the online phase, and their offline phase hinders throughput. This paper introduces Less-online/More-offline Signatures (LoMoS) to enable minimal end-to-end delay and high message throughput. LoMoS entails avoiding expensive operations entirely during the online phase. We present a construction that converts any digital signature scheme into LoMoS, retains its properties, and unlike existing solutions, benefits from shorter messages.

A number of applications in next-generation multi-hop networks impose low-latency requirements on data transmission thereby necessitating the underlying relays to introduce negligible delay when forwarding the packets. While traditional relaying techniques such as amplify-and-forward protocols may help the packets to satisfy latency-constraints, such strategies do not facilitate the destination in learning the provenance of the packets, which in turn could be used for either learning the topology of the network or detecting security threats on the network. With potential applications to vehicular networks, we address the design of provenance embedding algorithms that reduce the delays on the packets and yet assist the destination in determining their provenance. We propose double-edge (DE) embedding techniques, wherein a subset of the relay nodes in the path strategically skip the provenance embedding process to reduce the delays on the packets. Using bloom filters as tools to implement double-edge embedding, first, we derive upper bounds on the error-rates of the DE embedding techniques, and subsequently present experimental results on a test bed to demonstrate the efficacy of the proposed techniques. We show that the DE embedding techniques offer latency benefits up to 17 % along with remarkable reduction in error-rates in comparison with the baselines

In this paper, we propose a new adversarial attack on frequency-hopping-based wireless communication between two users, namely Alice and Bob. In this attack, the adversary referred to as Eve, instantaneously modifies the transmitted signal by Alice before forwarding it to Bob within the symbol period. We show that this attack forces Bob to incorporate Eve's signal in the decoding process; otherwise, treating it as noise would further degrade the performance akin to jamming. Through this attack, we show that Eve can convert a slow-fading channel between Alice and Bob to a rapid-fading one by modifying every transmitted symbol independently. As a result, neither pilot-assisted coherent detection techniques nor blind-detection methods are directly applicable as countermeasures. As potential mitigation strategies, we explore the applicability of frequency hopping along with on-off keying (OOK) and binary frequency-shift keying (BFSK) as modulation schemes. In the case of OOK, the attacker attempts to introduce deep fades on the tone carrying the information bit, whereas in the case of BFSK, the attacker pours comparable energy levels on the tones carrying bit-0 and bit-1, thereby degrading the performance. Based on extensive analyses and experimental results, we show that when using OOK, Bob must be equipped with a large number of receive antennas to reliably detect Alice's signal, and when using BFSK, Alice and Bob must agree upon a secret key to randomize the location of the tones carrying the bits, in addition to randomizing the carrier frequency of communication.

Location-Based Social Network (LBSN) applications that support geo-location-based posting and queries to provide location-relevant information to mobile users are increasingly popular, but pose a location-privacy risk to posts. We investigated existing LBSNs and location privacy mechanisms, and found a powerful potential attack that can accurately locate users with relatively few queries, even when location data is well secured and location noise is applied. Our technique defeats previously proposed solutions including fake-location detection and query rate limits. To protect systems from this attack, we propose a simple, scalable, yet effective defense that quantizes the map into squares using hierarchical subdivision, consistently returns the same random result to multiple queries from the same square for posts from the same user, and responds to queries with different distance thresholds in a correlated manner, limiting the information gained by attackers, and ensuring that an attacker can never accurately know the quantized square containing a user. Finally, we verify the performance of our defense and analyze the trade-offs through comprehensive simulation in realistic settings. Surprisingly, our results show that in many environments, privacy level and user accuracy can be tuned using two independent parameters; in the remaining environments, a single parameter adjusts the tradeoff between privacy level and user accuracy. We also thoroughly explore the parameter space to provide guidance for actual deployments.