{"title":"Bridging Functional Encryption and Secure Function Evaluation: Toward Efficient and Coercion-Resistant Multi-Party Systems","authors":"Rahat Naz, Jaydeep Howlader, Shahnawaz Ahmad","doi":"10.1002/cpe.70949","DOIUrl":"https://doi.org/10.1002/cpe.70949","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, a hybrid FE–SFE framework that combines distributed key generation, input masking, authenticated secret sharing, active verification, GPU acceleration, batching, compression and asynchronous communication was developed. The implementation was tested on a 10-node CPU-GPU cluster with Adult, MNIST and controlled benchmark vectors, 1000–10,000 records, and various security levels, with 2–10 parties. The framework maintained exact functional correctness across 287,000 valid evaluations, and all 80,000 injected malicious deviations were incorrectly evaluated without producing invalid output. The end-to-end latency was reduced by 41.06%–41.81% compared to sequential execution, and four-stream GPU encryption achieved 18,234 records/s. The overhead of the active verification and coercion protection was moderate. The communication volume decreased by 62.70% when the security metadata was added. The strong scaling efficiency remained above 81% up to 8 nodes, but dropped below the desired 75% at 10 nodes. The proposed framework provides a viable basis for secure multi-party analytics under controlled, security-aligned experimental conditions that can be used for rigorous and reproducible evaluations, while also being functional, verified, coercion-resistant, distributed, and performant.</p>\u0000 </div>","PeriodicalId":55214,"journal":{"name":"Concurrency and Computation-Practice & Experience","volume":"38 18","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148871948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"DIBOS: Dynamic Identity-Based Ordered Signatures With Timeout-Skip for Blockchain Document Approval","authors":"Zhanlin Wang, Ping Zhang","doi":"10.1002/cpe.70937","DOIUrl":"https://doi.org/10.1002/cpe.70937","url":null,"abstract":"<div>\u0000 \u0000 <p>In a document approval system, multiple signers must approve a document in strict chronological order. We propose a blockchain-based document approval system that integrates a dynamic identity-based ordered signature (DIBOS) scheme built on Sakai's identity-based signature. The DIBOS scheme supports two critical real-world features: (i) <i>dynamic signer updates</i> (insertion, deletion, or replacement of signers mid-approval while preserving prior signature validity) and (ii) <i>timeout-skip with backup signers</i> (automatic skipping of unresponsive signers with immutable audit logging). We formalize a strengthened <i>Order-Unforgeability with Skip</i> (OUf-S) security model and prove our scheme secure under it. Three smart contracts handle signer registration, document request delivery, and batch verification. We implement the off-chain signing on both Intel X64 and ARM64 platforms; dynamic operations add less than 12% overhead, making the system suitable for resource-constrained IoT devices. A full cost analysis on the Ethereum Goerli testnet demonstrates the practicality of the approach.</p>\u0000 </div>","PeriodicalId":55214,"journal":{"name":"Concurrency and Computation-Practice & Experience","volume":"38 18","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148872021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"TK-SMF: Top-K Semantic Mask Fusion With Dynamic Budget and Recovery Against Adversarial Patch Attacks Under Semantic Fragmentation in Vision Models","authors":"İbrahim Yaylalı, Alper Kılıç","doi":"10.1002/cpe.70908","DOIUrl":"https://doi.org/10.1002/cpe.70908","url":null,"abstract":"<div>\u0000 \u0000 <p>Deep learning-based vision models have severe security vulnerabilities against physical adversarial patch attacks. Previous studies propose explainability-based defense mechanisms (e.g., PatchOut and SALIUITL). These methods aim to recover the system by masking the regions that affect model decisions the most. However, these approaches generally assume that the adversarial effect is located in a single, continuous region (single mask selection). In this study, we empirically demonstrate the “Semantic Fragmentation” and saliency bleeding problems caused by multiple scattered patches in explainability maps. To overcome this issue, we propose the “Top-K Semantic Mask Fusion with Dynamic Budget (TK-SMF)” system. The proposed framework initially extracts explainability maps using LayerGradCAM, subsequently constructs a pool of candidate semantic segments via the Fast Segment Anything Model (FastSAM), and ultimately fuses the Top-K highest-risk masks within a strictly fixed area budget. This budget is anchored to a predefined worst-case threat assumption, eliminating the need to know the attacker's actual patch count during inference. We then restore the selected masked areas using OpenCV Inpainting to achieve model recovery. We evaluated the proposed framework on 38 distinct and challenging physical-world scenarios, encompassing diverse tactical vehicle categories under single- and multipatch attacks. Experimental results prove that TK-SMF breaks the targeted attack illusion with a 100% success rate. The results show that dynamic and flexible defense architectures exceed the limits of the single-mask assumption. They significantly improve model accuracy and reliability against complex physical world threats.</p>\u0000 </div>","PeriodicalId":55214,"journal":{"name":"Concurrency and Computation-Practice & Experience","volume":"38 17","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PDCFL: Prototype-Driven Decoupled Clustered Federated Learning for Non-IID Data","authors":"Yazhi Liu, Bo Hong, Zhigang Yang, Wei Li","doi":"10.1002/cpe.70922","DOIUrl":"https://doi.org/10.1002/cpe.70922","url":null,"abstract":"<div>\u0000 \u0000 <p>Federated Learning (FL) is prone to convergence instability and degraded personalization capability under non-independent and identically distributed (non-IID) data conditions. This article proposes a prototype-driven decoupled clustered federated learning (PDCFL) framework to address the limitations of existing prototype-based methods in terms of clustering robustness, prototype discriminability, and cluster-level personalization. Hybrid clustering based on the prototype method is proposed, which combines DBSCAN to filter out low-density client prototypes and leverages spectral clustering to capture nonlinear relationships in the prototype space, thereby achieving robust client clustering. However, to mitigate the suboptimal global knowledge caused by prototype discrimination degradation, we devise a prototype space optimization mechanism based on NT-Xent that alleviates insufficient prototype discriminability by promoting intra-cluster aggregation and increasing intercluster distance. Furthermore, an adaptive model decoupling strategy is introduced to address the remaining intra-cluster heterogeneity. This strategy dynamically adjusts the ratio of shared parameters to personalized parameters according to the similarity between client prototypes and cluster center prototypes, thereby constructing a fine-grained personalized model for each client. On the Digits-5 dataset under the feature & label shift setting, PDCFL achieves an accuracy improvement of 3.52%; under the label shift setting, the method achieves an average improvement of 9.05% across five domains.</p>\u0000 </div>","PeriodicalId":55214,"journal":{"name":"Concurrency and Computation-Practice & Experience","volume":"38 17","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"DAV-Diff: A Diffusion Model for High-Quality Remote Sensing Image Reconstruction Based on Multi-Level Attention and \u0000 \u0000 \u0000 v\u0000 \u0000 $$ v $$\u0000 -Prediction","authors":"Shanxu Wu, Lihua Tian, Chen Li","doi":"10.1002/cpe.70913","DOIUrl":"https://doi.org/10.1002/cpe.70913","url":null,"abstract":"<div>\u0000 \u0000 <p>With the advancement of deep learning, diffusion models have gained prominence as a powerful method for high-fidelity image generation by progressively removing noise to restore structural and textural details. In remote sensing image super-resolution (RSISR), which typically utilizes paired high-resolution (HR) and low-resolution (LR) images for supervised training, applying diffusion models directly faces three persistent challenges. First, common preprocessing techniques such as bicubic interpolation lose substantial prior information, resulting in a lack of high-frequency details and weakened spatial structural features. Second, existing denoising networks often exhibit insufficient global modeling capability, performing poorly in capturing long-range spatial relationships and evaluating channel-wise feature importance. Third, traditional noise prediction (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ϵ</mi>\u0000 </mrow>\u0000 <annotation>$$ epsilon $$</annotation>\u0000 </semantics></math>-prediction) struggles to restore fine details under high-noise conditions, frequently failing to preserve the complex structures of ground objects in remote sensing scenes. To address these issues, this paper proposes DAV-Diff, a fast-sampling conditional diffusion model for RSISR. DAV-Diff coordinates three task-oriented components to improve conditional prior representation, long-range dependency modeling, and high-noise detail recovery in RSISR. The first is a multi-dilated residual attention block (MD-RAB), which enhances the extraction of prior information from LR images and compensates for detail loss caused by interpolation. The second component is a dual-attention mechanism embedded within the denoising network to strengthen long-range spatial dependency modeling and adaptive channel feature weighting. The third is a residual-domain <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>v</mi>\u0000 </mrow>\u0000 <annotation>$$ v $$</annotation>\u0000 </semantics></math>-prediction strategy that replaces traditional noise prediction, mitigating detail degradation in high-noise environments while preserving structural features of complex ground objects. Experimental results show the effectiveness of DAV-Diff against state-of-the-art methods; ablation studies, computational complexity analysis, and sampling-step sensitivity experiments further quantify the contribution and efficiency of each component.</p>\u0000 </div>","PeriodicalId":55214,"journal":{"name":"Concurrency and Computation-Practice & Experience","volume":"38 17","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}