arXiv subjects

Tadashi Nakano

Publications and source records attributed to Tadashi Nakano.

5 recordsLinked to original sources

arXiv2026

Transparent Identity Verification Approach Using MPC and Efficient Credential Status Handling

A secure and privacy-preserving identity verification process is essential for digital ecosys- tems. Current eKYC frameworks that rely on Zero-Knowledge Proofs (ZKPs) face high computational cost, rigid circuit design, complex integration, and expensive on-chain verification. The W3C 2021 BitString- based credential status mechanism also suffers from inefficient updates and poor scalability in large- scale deployments. We propose a transparent and cost-effective identity verification framework based on Multi-Party Computation (MPC). It enables private off-chain code execution and produces runtime proofs anchored to a blockchain. The framework introduces a multidimensional bit-matrix model with efficient compression. Using ZSTD, the credential data is reduced to 76 bytes compared to 140 bytes with GZIP, cutting storage and bandwidth costs. The system also supports fine-grained status updates and Layer-2 blockchain anchoring for tamper-evident, low-cost verification. The system employs reusable verifiable presentations (VPs) with unique access tokens, enabling cost-free verification and stronger access control. Selective disclosure preserves user control and strengthens privacy. Finally, the system integrates SHA3 hashing and Falcon post-quantum signatures. This guarantees robustness against quantum attacks, transparency, and scalability. It is a future-proof solution for national-scale identity verification, as demonstrated by experimental findings and security studies that validate its robustness and applicability.

cs.CR↗

arXiv2026

Continual Learning of Feedback-based Molecular Communication

This paper proposes and evaluates a new performance estimation method that leverages continual learning (CL) algorithms to carry out sequential simulation experiments for a feedback-based molecular communication protocol. As the protocol is sequentially examined in various experimental settings, the proposed CL-based performance estimators incrementally learn a series of unexperienced estimation tasks without compromising those that have been learned in the past. They are designed to work on a standard neural network architecture by customizing regularization and replay strategies in the loss function. Experimental results demonstrate that the proposed estimators can effectively learn on a continuous stream of simulation results and enhance the baseline neural network by improving estimation accuracy at a variety of computational costs. This paper's contribution is to establish the implications of CL in the field of molecular communication.

cs.LG↗

arXiv2018

Molecular Communications at the Macroscale: A Novel Framework for Modeling Epidemic Spreading and Mitigation

Using the notion of effective distance proposed by Brockmann and Helbing, complex spatiotemporal processes of epidemic spreading can be reduced to circular wave propagation patterns with well-defined wavefronts. This hidden homogeneity of contagion phenomena enables the mapping of virtual mobility networks to physical propagation channels. Subsequently, we propose a novel communications-inspired model of epidemic spreading and mitigation by establishing the one-to-one correspondence between the essential components comprising information and disease transmissions. The epidemic processes can be regarded as macroscale molecular communications, in which individuals are macroscale information molecules carrying messages (epidemiological states). We then present the notions of normalized ensemble-average prevalence (NEAP) and prevalence delay profile (PDP) to characterize the relative impact and time difference of all the spreading paths, which are analogous to the classical description methods of path loss and power delay profile in communications. Furthermore, we introduce the metric of root mean square (RMS) delay spread to measure the distortion of early contagion dynamics caused by multiple infection transmission routes. In addition, we show how social and medical interventions can be understood from the perspectives of various communication modules. The proposed framework provides an intuitive, coherent, and efficient approach for characterization of the disease outbreaks by applying the deep-rooted communications theories as the analytical lens.

physics.soc-ph↗

arXiv2016

RNA as a Nanoscale Data Transmission Medium: Error Analysis

RNA can be used as a high-density medium for data storage and transmission; however, an important RNA process -- replication -- is noisy. This paper presents an error analysis for RNA as a data transmission medium, analyzing how deletion errors increase in a collection of replicated DNA strands over time.

cs.ET↗

arXiv2014

TCP-like molecular communications

In this paper, we present a communication protocol between a pair of biological nanomachines, transmitter and receiver, built upon molecular communications in an aqueous environment. In our proposal, the receiver, acting as a control node, sends a connection setup signal to the transmitter, which stokes molecules, to start molecule transmission. The molecules transmitted by the transmitter propagate in the environment and are absorbed by the receiver through its receptors. When the receiver absorbs the desired quantity of molecules, it releases a tear-down signal to notify the transmitter to stop the transmission. The proposed protocol implements a bidirectional communication by using a number of techniques originally designed for the TCP. In fact, the proposed protocol is connection-oriented, and uses the TCP-like probing to find a suitable transmission rate between transmitter and receiver so as to avoid receiver congestion. Unlike the TCP, however, explicit acknowledgments are not used, since they would degrade the communication throughput due to the large delay, a characteristic feature of molecular communications. Thus, the proposed protocol uses implicit acknowledgments, and feedback signals are sent by the receiver to throttle the transmission rate at the transmitter, i.e., explicit negative feedbacks. We also present the results of an extensive simulation campaign, used to validate the proposed protocol and to properly dimension the main protocol parameters.

cs.ET↗