As mixing services are increasingly being exploited by malicious actors for illicit transactions, mixing address association has emerged as a critical research task. A range of approaches have been explored, with graph-based models standing out for their ability to capture structural patterns in transaction networks. However, these approaches face two main challenges: label noise and label scarcity, leading to suboptimal performance and limited generalization. To address these, we propose HiLoMix, a graph-based learning framework specifically designed for mixing address association. First, we construct the Heterogeneous Attributed Mixing Interaction Graph (HAMIG) to enrich the topological structure. Second, we introduce frequency-aware graph contrastive learning that captures complementary structural signals from high- and low-frequency graph views. Third, we employ weak supervised learning that assigns confidence-based weights to noisy labels. Then, we jointly train high-pass and low-pass GNNs using both unsupervised contrastive signals and confidence-based supervision to learn robust node representations. Finally, we adopt a stacking framework to fuse predictions from multiple heterogeneous models, further improving generalization and robustness. Experimental results demonstrate that HiLoMix outperforms existing methods in mixing address association.

Cross-chain swaps are a crucial application that facilitates the transfer of digital assets across different blockchains, thereby enhancing the flexibility and availability of asset circulation. Ensuring atomicity is a fundamental objective for cross-chain swaps. The Hashed TimeLock Contract (HTLC) protocol is one of the primary solutions for cross-chain swaps. It ensures atomicity by statically partitioning execution actions for swap submission and asset refund along the time dimension. Such designs rely on a predictable upper bound on transaction confirmation time. However, this assumption does not hold in practical blockchain environments, leading to atomicity violations. To address this limitation, we propose Chuchu, a hashlock group protocol for cross-chain swaps. Chuchu abandons static partitioning along the time dimension and instead distinguishes swap submission and asset refund through explicitly defined asset locking states and their dynamic transitions. To cope with divergent execution progress across blockchains, Chuchu bounds execution progress divergence and introduces an exit-proof mechanism, ensuring that locked assets always have well-defined and consistent unlocking paths under all execution scenarios. The effectiveness and feasibility of Chuchu are demonstrated through theoretical analysis and formal verification using TLA+. Meanwhile, experiment results show that Chuchu reduces execution time by over 98% compared to the HTLC protocol in the case of swap rollbacks.

With the development of blockchain applications, demand for cross-chain technology has been increasing. Relay chain mode is the state-of-the-art and mainstream solution nowadays. However, the relay chain mode suffers from poor performance, which stems from its core facility – the relay chain. Therefore, guiding its improvement and parameters configuration is vital. Currently, there is no specialized performance model of the relay chain. The cross-chain scenario involves receiving transactions from blockchains and uniformly verifying them, while general blockchain models are not applicable for it. Relay chains are characterized by the following features: transaction arrival in batches with uncertain sizes, updating block headers for simplified payment verification (SPV), Byzantine fault tolerance (BFT) type protocol, and different packaging rules. This work first proposes an analytical framework for relay chain performance. It captures the mentioned features by constructing a batch-arrival and bulk-service model. We give a concrete calculation of the relay chain with practical BFT (PBFT) consensus and develop a method to arrive at the computational forms of two essential performance descriptors: system throughput and cross-chain transaction confirmation delay. Through this model, we can judge accurately whether the relay chain is overloaded, and eliminate the overload state by tuning the parameters; and we can evaluate the system performance under different traffic and design parameters. Finally, we verify the model through experiments. With our study, operators can configure the system parameters effectively and improve the relay chain to meet the requirements of practical use.

As the requirements of different application scenarios vary, numerous blockchains have been developed. Among them, chains using Byzantine Fault Tolerance consensus (BFT chains for short) occupy a dominant position. Performance modeling is the most common method for guiding chain design and configuration. However, many lack specific models due to the large number of BFT chains. Providing a general framework for them is promising and should demonstrate two important features that BFT chains may differ in: different consensus stages and different packaging rules. This paper is the first to propose a general framework applicable to various BFT chains. We use the bulk-service model in queuing theory to reflect the above two features of various BFT chains and provide calculation methods for them. We give an expression for the confirmation delay of transactions (TXs for short) in the chain and verify it through experiments on various BFT chains. We also use the model for a brief analysis to assist designers in configuring and designing BFT chains.

With the emergence of various application scenarios, various chains have been developed to meet their requirements. Among them, chains with fixed block intervals (fixed chains for short) occupy an increasingly significant position. Performance has always been a key bottleneck of blockchains and modeling for them is the most common method for performance analysis. But til now, few models for fixed chains exist and they are not precise and applicable enough. This paper proposes a model for fixed chains via the bulk-service queuing theory, which can reflect the real scenario more precisely and apply to the high load. We consider the continuous time and the transaction (TX for short) pool with limited capacity and reflect the chains’ features of fixed intervals and empty blocks to improve accuracy and applicability. We give an expression for three significant measurements: the average confirmation delay of TXs, the blockchain throughput, and the TX rejection rate. We use Ethereum to validate our model. And moreover, we use the model for analysis to assist designers in operating chains.

Hashed Timelock Contract (HTLC) is a widely-used protocol for cross-chain asset swaps. However, it relies on serial asset-locking to guarantee atomicity, which causes high latency and poor fairness. Aiming at the drawbacks of HTLC, we propose Lilac, a cross-chain asset swap protocol that supports parallel asset-locking. Lilac replaces the unique asset-unlocking credential in HTLC with multiple sub-credentials generated by all participating users, and the sequence of sub-credentials is used as the complete asset-unlocking credential. Users obtain the complete credential only when all assets have been locked, and the credential construction process is independent of the order in which assets are locked, so atomicity can be guaranteed when users lock their assets in parallel. Experiments show when a swap involves 2 to 4 blockchains, Lilac reduces the swap latency by 36.75% to 62.20%. Moreover, Lilac reduces the waiting time gap between different users so the fairness of a swap is improved.

Wi-Fi Protected Access II Pre-Shared Key (WPA2-PSK) is a hot way to wireless security in public Wi-Fi networks. It works on a pre-configured passphrase shared with all stations in the same Wi-Fi network. Session keys (e.g., Pairwise Transient Key, PTK) between stations and the access point (AP) are derived from the passphrase. The WPA2-PSK networks can authenticate external stations, however, they fail to guarantee confidential communication if internal attackers own the passphrase in the network since all stations derive their PTK using the same passphrase. To prevent internal stations from eavesdropping the PTK, a secure session key negotiation scheme in WPA2-PSK Networks (SSKNS) is proposed. We introduce a temporary session key (TSK), which is encrypted using elliptic curve cryptography (ECC) and exchanged securely between the station and the AP in the Wi-Fi association process. Through AES algorithm with TSK, the station encrypts its own nonce used to generate the unique PTK in the 4-way process. Our scheme neither modifies the legacy process related to PTK generation nor adds plethoric overhead on excessive protection of all messages. Security analysis and simulations performed in NS-3 demonstrate that by consuming a few computation overheads, SSKNS can effectively provide security level, compared with the existing schemes.

Blockchain can be used to ensure trust in a decentralized environment in which no trusted authority is available. Its original idea is to collect transactions in a block, and to chain the blocks together in such a way that attackers cannot forge the chain if the majority of the network is honest. Since its creation in 2008, blockchain technology has been used broadly in Internet to support decentralized payments, cloud computing, publishing, etc. This work focuses on public permissionless blockchain which neither guards against bad actors nor enforces access control. Named data networking (NDN) uses name-based routing and in-networking caching to support efficient content delivery, making it a promising future Internet architecture as well as a great network technology which can improve blockchain data delivery. Therefore, it is a very necessary task to enable deployment of blockchain applications over NDN. However, NDN is not immediately compatible with typical blockchain, since (permissionless) blockchain applications usually require broadcasting transactions and blocks in real time, which is not supported by the “pull” design of NDN. In this work, we propose BoNDN which enables blockchain applications over NDN. Unlike previous work, BoNDN follows the core design of NDN. We treat each type of blockchain data needed to be broadcast individually. Specifically, we rely on Interest broadcasting to support real-time broadcasting of blockchain transactions, which is small in size and can be brought by an Interest packet. In addition, we propose a subscription-push approach to support broadcasting of blockchain blocks, in which each miner performs subscription, and once a block is generated, the subscribed miner will receive the block.

Full-duplex (FD) wireless is an attractive PHY technology with high potential to improve the throughput of WLAN due to bidirectional transmissions. However, existing FD MACs fail to fully take advantage of bidirectional transmissions because of neglecting a feature of FD wireless that whether to build bidirectional transmissions relies on the queuing state of peers. In this paper, we design PQ-MAC, the first FD MAC which exploits more bidirectional transmission opportunities by leveraging peers' queuing information. Since PQ-MAC seizes the neglected but important feature, PQ-MAC can improve the performance with a slight transmission overhead. Simulations show that, in a 1-cell FD WLAN, PQ-MAC can achieve higher throughput than existing MACs when the buffer of AP is relatively small (≤200 frames). When the buffer of AP is relatively large (>200 frames), PQ-MAC can reduce the queuing delay without the loss of throughput.

This paper is concerned with the adaptation to multi-feature preferences on personalized search. In the existing work, the personalized search mainly leverages semantic features extracted from user history and ignores other non-semantic latent features, lets alone adapt to preference distribution on non-semantic features. To tackle this problem, we propose an adaptive model for multi-feature preferences, in which we adapt latent non-semantic features extracted from visited pages to reflect diverse aspects of user preferences. We also utilize a novel algorithm in our model to improve the adaptation for diverse preference distribution on these features for different users. Our experimental results demonstrate that our model can improve personalized search performance by enhanced adaptation to diverse user preferences.

The home agent can be a single point of failure in mobile IPv6 networks. Fault tolerance can be used to provide reliable home agent service. This paper proposes a home agent fault-tolerant method for mobile IPv6 networks. All home agents are formed into the structure of ring detection & backup chain by sorting them using a deterministic sorting algorithm, in which each home agent backups its bindings on the next adjacent home agent and its validation is monitored by the adjacent home agents. Each home agent is not only an active home agent, but also a standby one. Service takeover is fleetly implemented by the single replica of mobility bindings. Simulation results show that our method has less service break time and less global signal cost.

Recently, the IETF MIPSHOP working group proposes Fast PMIPv6 (FPMIPv6) and Transient Binding PMIPv6 (TPMIPv6) to reduce the handover latency and packets loss of PMIPv6. The research and standardization of FPMIPv6 and TPMIPv6 are just in the initial stage. The system performance analysis of them is benefit to the protocol design and deployment. In this paper, through the theoretical analysis and system simulation, we evaluate the handover latency of PMIPv6, FPMIPv6 and TPMIPv6 in vertical handover environment. Furthermore, in order to reflect handover performance more comprehensively, in system simulation, we also evaluate the UDP packets loss rate and the TCP throughput declining degree of such protocols. The results of theoretical analysis and simulation show that: (1) in vertical handover, the handover latency of FPMIPv6 is much larger than TPMIPv6 and PMIPv6. But the UDP packet loss rate of FPMIPv6 is smaller than TPMIPv6 and PMIPv6; (2) the handover performance of FPMIPv6-pre and TPMIPv6 much depend on MN's residence time in signal overlapped area.

Trust relationship among multiple domains is the basis for inter-domain fast authentication. This paper proposes a fast authentication method combining inter-domain trust relationship for wireless mobile IPv6 networks. In order to implement inter-domain trust relationship, a dynamic trust maintenance mechanism is designed. Based on Combined Public Key (CPK) algorithm, a new signature and verification scheme is applied to accelerate the authentication process. This scheme supports the proposed trust-based mutual authentication between mobile node and the access network. Theoretical analysis and numerical results show that the proposed method is more effective in reducing authentication delay and signaling overhead. Additionally, the proposed method is proven to be tolerant of existential forgery and man-in-the-middle attacks.

In MIPv6, the home agent (HA) is the key entity to ensure a mobile nodepsilas (MN) reachability. A single HA on the home link will become a performance bottleneck. In order to enhance service availability and improve system performance, it is necessary to configure multiple HAs on the home link and efficiently balance load among these HAs. This paper proposes a dynamic multiple HA load balancing mechanism based on active overload prevention (DHALAOP). The solution actively prevents HA from overloading in advance, rather than just passively transferring excess load among HAs as previous load balancing mechanisms do. A novel dynamic weight load evaluation algorithm is introduced to provide the basis for optimal load balancing decision. In addition, DHALAOP utilizes single HA mirror image and load slicing scheme to achieve the transparency of load balancing and eliminate unnecessary additional overhead. The theoretical analysis results show that DHALAOP can be more efficient in enhancing service availability and improving system performance as compared with the previous mechanisms. At the same time it introduces a lower signaling cost.

Access authentication is very important for deploying mobile IPv6 networks. In this paper, we design a two-level hierarchical identity-based signature scheme, based on which we propose a new hierarchical authentication scheme for mobile IPv6 networks. Our solution adopts multi-level network access identifier (NAI) as public key, which simplifies key management in wireless mobile environment. The handover procedure integrating authentication is also cut down by our hierarchical solution. And our solution accomplishes mutual authentication between terminal and network. We propose the handover latency analytical model to evaluate handover latency. The results show that our solution is more efficient than others, especially when a terminal is far away from its home domain and moves frequently. Security analysis shows that the proposed scheme is sufficient for privacy and unforgeability. An extended version for access authentication in multi-hierarchical mobile IPv6 networks is discussed.