| 中西 瑠海 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, | 松本 健一, | 笹部 昌弘, | 張 元玉 |
|
title: IOTA-Based Access Control Framework for the Internet of Things
abstract: Due to the rapid penetration of IoT into our daily lives, there has been an increasingly urgent demand for effective IoT access control schemes to ensure the safety and privacy of people. Recently, IoT access control schemes based on the blockchain technology have attracted considerable attention. Although these schemes are promising to achieve decentralized and trustworthy access control, the limitations of long access request-processing time and poor scalability may hinder their application to practical IoT systems. To address these limitations, an access control scheme, called DCACI, has been proposed based on the emerging IOTA technology. The idea of the DCACI scheme is to store the access rights of subjects, in the format of tokens, into the IOTA Tangle. However, this scheme suffers from three main drawbacks: 1) providing no implementation of authorization; 2) requiring pre-established secure links between subjects and object owners; and 3) supporting only one-to-one access control. To solve these problems, we propose a novel access control scheme by combining the IOTA technology and the Ciphertext-Policy Attribute-Based Encryption (CP-ABE) technology. The proposed scheme enables access right authorization to a large number of subjects in a smaller number of operations in large-scale IoT networks, alleviating the burden of object owners. Moreover, the scheme also provides channel security between subjects and object owners by encrypting data using CP-ABE. We show the feasibility of our scheme by implementing a proof-of-concept prototype with IoT devices. language of the presentation: Japanese | ||||||
| 藤田 健太郎 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, | 松本 健一, | 笹部 昌弘, | 張 元玉 |
|
title: Pool Selection Problem in the Case of Unobservable BWH Attack
abstract: Mining, the process where multiple miners compete to add blocks to Proof-of-Work (PoW) blockchain, is of great importance to maintain the tamper-resistance feature of blockchain. In current blockchain networks, miners usually form groups, called mining pools, to improve their revenues. When multiple pools exist, a fundamental mining pool selection problem arises: which pool should each miner join to maximize its revenue? Also, the existence of mining pools leads to another critical issue, i.e., Block WithHolding (BWH) attack, where a pool sends some of its miners as spies to another mining pool to gain extra revenues without contributing to the mining of the infiltrated pool. Although the pool selection problem in the presence of BWH attack has been investigated in previous studies, they assume that the BWH attack is observable from miners, which is impractical. This research therefore investigates the mining pool selection issue in the case of unobservable BWH attack. We apply the reinforcement learning (RL) technique to model the dynamic mining pool selection processes of intelligent miners. Simulation results showed that, by using the RL technique, miners can gradually acquire the optimal action policy as the learning process continues. language of the presentation: Japanese | ||||||
| 松永 赳尭 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, | 松本 健一, | 笹部 昌弘, | 張 元玉 |
|
title: An Incentivization Scheme for Participating Nodes in Proof-of-Stake-Based Blockchain
abstract: The Proof of Stake (PoS) protocol is one of consensus algorithms for Blockchain, in which the integrity of a new block is validated according to voting by nodes called validators. Due to validator-oriented voting, however, voting results are likely to be false when the number of validators who wrongly vote increases. In the PoS protocol, validators are motivated to vote correctly by reward and penalty mechanism. With this mechanism, validators who contribute to correct consensuses are rewarded, while those who make incorrect block confirmation are penalized. In this presentation, we consider a reward-penalty mechanism based on the voting profile of a validator, which is estimated from the voting history of the validator. We evaluate the performance of the proposed mechanism by computer simulation, investigating the impact of system parameters on the estimation accuracy of the validator profile and the amount of validator's stake. Numerical results show that the proposed algorithm can estimate the voting profile of a validator accurately even when the voting profile dynamically changes. It is also shown that the proposed mechanism gives more reward to validators with high voting profile. language of the presentation: Japanese | ||||||
| 源 芳朗 | M, 2回目発表 | 大規模システム管理 | 笠原 正治, | 松本 健一, | 笹部 昌弘, | 張 元玉 |
|
title: Reward Distribution Mechanism for Blockchain-Based Scientific and Technical Paper Publish Systems
abstract: In the publishing mechanism of scientific and technical papers, publishing companies serve as intermediaries between authors, reviewers, and readers. The existence of publishing companies usually introduce heavy monetary cost to both readers and authors, and delay the proliferation of new scientific findings. To solve these problems, research efforts have been devoted to seeking alternatives of publishing companies, among which blockchain-based publish systems have attracted considerable attention. One representative blockchain-based publish system is called EUREKA, which relies on a reward system to distribute reward to the participants involved in the publication process. The EUREKA reward system distributes almost constant amounts of reward to reviewers without considering the quality of the reviews and the reputation of reviewers, resulting in poor incentive for reviewers and unfair reward distribution. In this study, we aim to improve the EUREKA reward system by incorporating the reputation of reviewers and the quality of their reviews. To achieve this goal, we first design a reputation evaluation scheme, which calculates the reputation of a reviewer based on several metrics, like number and quality of published papers and number and quality of reviews. We then propose a reward system that enables the reward to be distributed to reviewers based on the quality of their reviews and their reputations. language of the presentation: Japanese | ||||||