The rise of Web3 social ecosystems signifies the dawn of a new chapter in digital interaction, offering significant prospects for user engagement and financial advancement. Nonetheless, this progress is shadowed by potential privacy concessions, especially as these platforms frequently merge with existing Web2.0 social media accounts, amplifying data privacy risks for users. In this study, we investigate the nuanced dynamics between user engagement on Web3 social platforms and the consequent privacy concerns. We scrutinize the widespread phenomenon of fabricated activities, which encompasses the establishment of bogus accounts aimed at mimicking popularity and the deliberate distortion of social interactions by some individuals to gain financial rewards. Such deceptive maneuvers not only distort the true measure of the active user base but also amplify privacy threats for all members of the user community. We also find that, notwithstanding their attempts to limit social exposure, users remain entangled in privacy vulnerabilities. The actions of those highly engaged users, albeit often a minority group, can inadvertently breach the privacy of the larger collective. By casting light on the delicate interplay between user engagement, financial motives, and privacy issues, we offer a comprehensive examination of the intrinsic challenges and hazards present in the Web3 social milieu. We highlight the urgent need for more stringent privacy measures and ethical protocols to navigate the complex web of social exchanges and financial ambitions in the rapidly evolving Web3.
The InterPlanetary File System (IPFS) has recently gained considerable attention. While prior research has focused on understanding its performance characterization and application support, it remains unclear: (1) what kind of files/content are stored in IPFS, (2) who are providing these files, (3) are these files always accessible, and (4) what affects the file access performance. To answer these questions, in this paper, we perform measurement and analysis on over 4 million files associated with CIDs (content IDs) that appeared in publicly available IPFS datasets. Our results reveal the following key findings: (1) Mixed file accessibility: while IPFS is not designed for a permanent storage, accessing a non-trivial portion of files, such as those of NFTs and video streams, often requires multiple retrieval attempts, potentially blocking NFT transactions and negatively affecting the user experience. (2) Dominance of NFT (non-fungible token) and video files: about 50% of stored files are NFT-related, followed by a large portion of video files, among which about half are pirated movies and adult content. (3) Centralization of content providers: a small number of peers (top-50), mostly cloud nodes hosted by tech companies, serve a large portion (95%) of files, deviating from IPFS's intended design goal. (4) High variation of downloading throughput and lookup time: large file retrievals experience lower average throughput due to more overhead for resolving file chunk CIDs, and looking up files hosted by non-cloud nodes takes longer. We hope that our findings can offer valuable insights for (1) IPFS application developers to take into consideration these characteristics when building applications on top of IPFS, and (2) IPFS system developers to improve IPFS and similar systems to be developed for Web3.
Melanie Swan, Takashi Kido, Eric Roland, Renato P. dos Santos
Health Agents are introduced as the concept of a personalized AI health advisor overlay for continuous health monitoring (e.g. 1000x/minute) medical-grade smartwatches and wearables for “healthcare by app” instead of “sickcare by appointment.” Individuals can customize the level of detail in the information they view. Health Agents “speak” natural language to humans and formal language to the computational infrastructure, possibly outputting the mathematics of personalized homeostatic health as part of their reinforcement learning agent behavior. As an AI health interface, the agent facilitates the management of precision medicine as a service. Healthy longevity is a high-profile area characterized by the increasing acceptance of medical intervention, longevity biotech venture capital investment, and global priority as 2 billion people will be over 65 in 2050. Aging hallmarks, biomarkers, and clocks provide a quantitative measure for intervention. Some of the leading interventions include metformin, rapamycin, spermidine, NAD+/sirtuins, alpha-ketoglutarate, and taurine. AI-driven digital biology, longevity medicine, and Web3 personalized healthcare come together in the idea of Health Agents. This Web3 genAI tool for automated health management, specifically via digital-biological twins and pathway2vec approaches, demonstrates human-AI intelligence amplification and works towards healthy longevity for global well-being.
This study proposes a framework to enhance privacy in Blockchain-based Internet of Things (BIoT) systems used in the healthcare sector. The framework addresses the challenge of leveraging health data for analytics while protecting patient privacy. To achieve this, the study integrates Differential Privacy (DP) with Federated Learning (FL) to protect sensitive health data collected by IoT nodes. The proposed framework utilizes dynamic personalization and adaptive noise distribution strategies to balance privacy and data utility. Additionally, blockchain technology ensures secure and transparent aggregation and storage of model updates. Experimental results on the SVHN dataset demonstrate that the proposed framework achieves strong privacy guarantees against various attack scenarios while maintaining high accuracy in health analytics tasks. For 15 rounds of federated learning with an epsilon value of 8.0, the model obtains an accuracy of 64.50%. The blockchain integration, utilizing Ethereum, Ganache, Web3.py, and IPFS, exhibits an average transaction latency of around 6 seconds and consistent gas consumption across rounds, validating the practicality and feasibility of the proposed approach.
Penelitian ini bertujuan mengimplementasikan "NFT Pack" dalam ekosistem game Web3 di blockchain Solana dengan menggunakan teknologi State Compression untuk meningkatkan efisiensi dan keamanan transaksi NFT. Melalui integrasi paket NFT yang mendukung lebih dari satu NFT, penelitian ini bertujuan memberikan inovasi baru bagi pemain game Web3. Dengan penerapan State Compression, biaya transaksi dapat dikurangi dan efisiensi penyimpanan data ditingkatkan. Hasil penelitian menunjukkan bahwa implementasi NFT Pack dengan State Compression berhasil, dengan smart contract yang memfasilitasi pembelian, penjualan, dan interaksi NFT dalam paket. Pengujian menunjukkan pengaruh positif terhadap biaya transaksi dan efisiensi tanpa mengurangi keamanan system yang ada sebelumnya. Kesimpulan menghasilkan bahwa studi kasus NFT Pack berhasil dan terbukti aman, serta menyoroti potensi besar implementasi ini dalam meningkatkan efisiensi transaksi dan pengalaman pengguna di ekosistem game Web3. Penggunaan State Compression pada Compressed NFT menghasilkan penghematan biaya yang signifikan kurang lebih 95,3% dibandingkan NFT biasa dan potensi skalabilitas lebih tinggi. Saran untuk penelitian mendatang meliputi penelitian lebih lanjut mengenai keamanan dan skalabilitas, serta pengembangan fitur inovatif untuk meningkatkan interaksi pengguna dengan NFT. Kata Kunci— Blockchain, Non-Fungible Token, Smart Contract, Solana, Compressed NFT.
The advent of Web3 technologies promises unprecedented levels of user control and autonomy. However, this decentralization shifts the burden of security onto the users, making it crucial to understand their security behaviors and perceptions. To address this, our study introduces a comprehensive framework that identifies four core components of user interaction within the Web3 ecosystem: blockchain infrastructures, Web3-based Decentralized Applications (DApps), online communities, and off-chain cryptocurrency platforms. We delve into the security concerns perceived by users in each of these components and analyze the mitigation strategies they employ, ranging from risk assessment and aversion to diversification and acceptance. We further discuss the landscape of both technical and human-induced security risks in the Web3 ecosystem, identify the unique security differences between Web2 and Web3, and highlight key challenges that render users vulnerable, to provide implications for security design in Web3.
Litao Ye, Bin Chen, Shrivastava Shivanshu, Chen Sun · 7 authors
Centralized Dynamic Spectrum Sharing (DSS) faces challenges like data security, high management costs, and limited scalability. To address these issues, a blockchain-based DSS scheme has been proposed in this paper. First, we utilize the ERC4907 standard to mint Non-Fungible Spectrum Tokens (NFSTs) that serve as unique identifiers for spectrum resources and facilitate renting. Next, we develop a smart contract for NFST auctions, ensuring secure spectrum transactions through the auction process. Lastly, we create a Web3 spectrum auction platform where users can access idle spectrum data and participate in auctions for NFST leases corresponding to the available spectrum. Experimental results demonstrate that our NFST, designed according to the ERC4907 standard, effectively meets users' secure and efficient DSS requirements, making it a feasible solution.
Blockchain and NFT tokens will play an important role in the technology sector in the near future, and this process may help us to prevent scams in online exchange products as well as generate worthy trust in society. Hundreds of complaints have been filed in which the buyer or seller claimed to be defense personnel and displayed fake ID proofs to gain trust. Because Traditional Marketplace currently lacks a feature for reviewing sellers, users who want to buy products have little doubt about whether the seller can be trusted with the items they sell. Users can use it to determine whether a seller is reliable or not. Also, as a reference for purchasing items from the seller using NFT tokens. The Web3 is advancing more quickly in our society. Hopefully, it will have the widest possible audience for its reliable exchange, ownership transparency, and certified products. An NFT marketplace is a gateway to trade digital assets.The latest web assets, from simple artwork to expensive asset exchange, are available for purchase and sale on the NFT marketplace. Non-fungible tokens' ownership verification capabilities are their main advantage. Given that they are on a blockchain network, NFTs can help to link ownership to a single account. Since the blockchain can permanently store information about the product, checking for rarity and authenticity will soon be a thing on physical products too. In the rapidly evolving landscape of online marketplaces, the emergence of NFT (Non-Fungible Token) technology has ushered in a new era for both the sale of new and used products. This abstract delves into the dynamics of an NFT marketplace that caters to a diverse range of commodities, offering a seamless platform for buyers and sellers alike. This innovative marketplace leverages blockchain technology to tokenize both new and used products, providing each item with a unique digital identity that is securely stored on the blockchain. The use of NFTs ensures authenticity and provenance, instilling trust among users and mitigating the risk of counterfeit goods. The platform employs smart contracts to automate transactions, streamlining the buying and selling process while reducing the need for intermediaries.
He Peng, Yao Sun, Jianli Hao, Chunjiang An · 5 authors
Ground transportation, which includes the road and rail sectors, is a major source of greenhouse gas (GHG) emissions. An emissions trading system (ETS) is one of the environmental policies for controlling carbon emissions from fossil fuel combustion during transport activities. To investigate the status of existing ETS interventions on ground transportation emissions, a comprehensive literature review is conducted, including policy evaluation and comparison, scheme optimization and design, and specific transport behavior interventions. The results show that existing upstream policies are insufficient in stringency and effectiveness, while policy implementation for downstream interventions remains limited. To address these shortcomings, this study proposes a downstream ground transportation emissions trading system (GTETS), incorporating the Internet of Things and blockchain technology. As well as road and rail transportation emissions, the system includes the emissions-related activities of individuals and transportation companies, and its Web3-based technologies provide effective and efficient monitoring, reporting, and verification.
This paper closely examines a discussion paper by the National Institution for Transforming India (NITI) Aayog and a strategy paper by the Ministry of Electronics & Information Technology (MeitY) advocating non-financial use cases of blockchain in India. By noting the discursive shift from transparency to trust to adjustably transparent enacted in these two documents, and consequently the Indian state’s re-description of blockchain, the paper foregrounds how blockchain systems are being designated as “decentral” but have recentralizing effects where the state reinvents and re-establishes itself as an intermediary. This paper illustrates how discursive shifts concerning trust, transparency, (de)centralization and (dis)intermediation are crucial sites for investigating re-descriptions of emerging sociotechnical systems.
Primavera De Filippi, Morshed Mannan, Sofia Cossar, Tara Merk · 8 authors
While the evolution of the World Wide Web has taken various turnsaway from its original vision, the advent of Web3 promises a newera focused on user ‘ownership’ and ‘decentralization.’ Theconcept of Web3, introduced in 2014 by Ethereum co-founder andPolkadot creator Gavin Wood, focuses on a new infrastructurebased on decentralized networks and technologies. This newinfrastructure enhances user ownership and autonomy by movingaway from centralized operators and trusted intermediaries.Blockchain technology is a cornerstone of Web3, initiallydeveloped as an innovative means to record transactions digitally.The collective choices of individuals and organizations drive theevolution of blockchain technology and its diverse applications.These entities form what are known as ‘blockchain systems’:complex techno-social structures that operate across multipleintertwined layers. Beyond the capabilities of blockchaintechnology to store data across multiple nodes, the governancedynamics within blockchain systems are complex and nuanced. Tofully grasp the opportunities and challenges of Web3, it is essentialto analyze the governance practices of its fundamentalcomponents, including blockchain networks.This report is a collaborative effort between BlockchainGov andProject Liberty Institute to analyze the governance dynamics ofprominent blockchain networks through an interdisciplinary andcomparative lens. It focuses on eleven blockchain networks:Avalanche, Bitcoin, Cardano, Cosmos, Ethereum, Filecoin,Optimism, Polygon, Polkadot, Tezos, and Zcash. Through acomprehensive empirical analysis built on previous academic workand practitioners’ insights, the report offers six key findings aboutthe governance dynamics of these blockchain systems.
I Gede Agus Krisna Warmayana, Yuichiro Yamashita, Nobuto Oka "Decentralized Materials Data Management using Blockchain, Non-Fungible Tokens, and Interplanetary File System in Web3" Journal of Applied Data Sciences, 2025, Vol.6, No.1, p.742-752 https://doi.org/10.47738/jads.v6i1.380 掲載
The article closely reads a discussion paper by the National Institution for Transforming India (NITI) Aayog and a strategy paper by the Ministry of Electronics and Information Technology (MeitY) advocating non-financial use cases of blockchain in India. By noting the discursive shift from transparency to trust to adjustably transparent enacted in these two documents, and consequently the Indian state's redescription of blockchain, the paper foregrounds how blockchain systems are being designated as "decentral" but have recentralizing effects where the state reinvents and re-establishes itself as an intermediary. The paper illustrates how discursive shifts concerning trust, transparency, (de)centralization and (dis)intermediation are crucial sites for investigating redescriptions of emerging sociotechnical systems.
BACKGROUND: A blockchain can be described as a distributed ledger database where, under a consensus mechanism, data are permanently stored in records, called blocks, linked together with cryptography. Each block contains a cryptographic hash function of the previous block, a timestamp, and transaction data, which are permanently stored in thousands of nodes and never altered. This provides a potential real-world application for generating a permanent, decentralized record of scientific data, taking advantage of blockchain features such as timestamping and immutability. IMPLEMENTATION: Here, we propose INNBC DApp, a Web3 decentralized application providing a simple front-end user interface connected with a smart contract for recording scientific data on a modern, proof-of-stake (POS) blockchain such as BNB Smart Chain. Unlike previously proposed blockchain tools that only store a hash of the data on-chain, here the data are stored fully on-chain within the transaction itself as "transaction input data", with a true decentralized storage solution. In addition to plain text, the DApp can record various types of files, such as documents, images, audio, and video, by using Base64 encoding. In this study, we describe how to use the DApp and perform real-world transactions storing different kinds of data from previously published research articles, describing the advantages and limitations of using such a technology, analyzing the cost in terms of transaction fees, and discussing possible use cases. RESULTS: We have been able to store several different types of data on the BNB Smart Chain: raw text, documents, images, audio, and video. Notably, we stored several complete research articles at a reasonable cost. We found a limit of 95KB for each single file upload. Considering that Base64 encoding increases file size by approximately 33%, this provides us with a theoretical limit of 126KB. We successfully overcome this limitation by splitting larger files into smaller chunks and uploading them as multi-volume archives. Additionally, we propose AES encryption to protect sensitive data. Accordingly, we show that it is possible to include enough data to be useful for storing and sharing scientific documents and images on the blockchain at a reasonable cost for the users. CONCLUSION: INNBC DApp represents a real use case for blockchain technology in decentralizing biomedical data storage and sharing, providing us with features such as immutability, timestamp, and identity that can be used to ensure permanent availability of the data and to provide proof-of-existence as well as to protect authorship, a freely available decentralized science (DeSci) tool aiming to help bring mass adoption of blockchain technology among the scientific community.
Open access
Blockchain Technology Applications and Security
Cryptography and Data Security
Physical Unclonable Functions (PUFs) and Hardware Security
In today’s world almost all hospital uses hardcopy for patient data store and for booking appointment. All patient data is available on paper and user need to manage that all over he goes. Consider ’A’ patient got admitted in City Pune, all his data is stored on paper and what medicines he took. All the info about his health is stored there. After someday ‘A’ patient gone to another city far away without carrying any documents and there he got and health emergency and is not in condition of speaking and need urgently help. But due to lack of info available about patient doctor could not urgently take decisions. So, to reduce this risk our system is developed. The distribution of Health records becomes a time consuming and expensive process when we use the traditional client-server healthcare data management system where each hospital/clinic maintains its own database of patients’ medical records. A patient’s treatment is further delayed if the patient moves from one hospital to another hospital across different regions or countries. Moreover, most of the time a patient must repeat several laboratory and radiology tests. So, to address this the patient’s medical data from different hospitals are stored in a Blockchain based storage making it easily accessible by patients and the hospitals. And the pharma company will be able to store the information of medicines and medicals will be available to verify the medicines if they are from trustworthy companies. Keyword - - Dapp, Web3.Js, CSS.
In the quickly developing landscape of Web3.0, ensuring the security and integrity of digital documents has become paramount. This abstract introduces a groundbreaking solution, "Web3.0 Document Security: Leveraging Blockchain Technology," which harnesses the power of blockchain to revolutionize document transmission and protection. This innovative system leverages the inherent characteristics of blockchain, such as immutability, transparency, and decentralization, to develop a secured and sealed environment for the exchange of digital documents. By utilizing smart contracts, cryptographic hashing, and decentralized storage, this application guarantees the confidentiality, integrity, and authenticity of documents in an interconnected Web3.0 world. This paper provides an overview of the key features, benefits, and implications of adopting a decentralized application as the foundation for secure document transmission in the era of Web3.0 . Keywords— Documents, Data Security, Data Integrity, Secure Transmission, Cryptography, Blockchain, Cloud Technology, Web3
Xavatar is a media, educational, and therapeutic platform specializing in immersive virtual reality (VR) and augmented reality (AR) content, as well as seamless interconnectivity across various devices such as mobiles, tablets, and computers. It is aimed at improving the lives of patients with chronic mobility and communication disorders, including dementia, Alzheimer's, autism, chronic immobility, isolation, and long-term hospitalization. The project represents a fusion of digital technologies including the Metaverse, artificial intelligence (AI), and Web3, all designed to enhance healthcare interactions and patient support. This opinion piece explores the transformative potential of Xavatar, highlighting its role in shaping future healthcare landscapes through innovative, empathetic, and engaging digital solutions.
Open access
Artificial Intelligence in Healthcare and Education
The greatest advantage that Web3 applications offer over Web 2.0 is the evolution of the data access layer. Opaque, centralized services that compelled trust from users are replaced by trustless, decentralized systems of smart contracts. However, the public nature of blockchain-based databases, on which smart contracts transact, has typically presented a challenge for applications that depend on data privacy or that rely on participants having incomplete information. This has changed with the introduction of confidential smart contract networks that encrypt the memory state of active contracts as well as their databases stored on-chain. With confidentiality, contracts can more readily implement novel interaction mechanisms that were previously infeasible. Meanwhile, in both Web 2.0 and Web3 applications the user interface continues to play a crucial role in translating user intent into actionable requests. In many cases, developers have shifted intelligence and autonomy into the client-side, leveraging Web technologies for compute, graphics, and networking. Web3's reliance on such frontends has revealed a pain point though, namely that decentralized applications are not accessible to end users without a persistent host serving the application. Here we introduce the Non-Fungible Program (NFP) model for developing self-contained frontend applications that are distributed via blockchain, powered by Web technology, and backed by private databases persisted in encrypted smart contracts. Access to frontend code, as well as backend services, is controlled and guaranteed by smart contracts according to the NFT ownership model, eliminating the need for a separate host. By extension, NFP applications bring interactivity to token owners and enable new functionalities, such as authorization mechanisms for oracles, supplementary Web services, and overlay networks in a secure manner. In addition...
William Sánchez, Larue Linder, Robert C. Miller, Amelia Hood · 5 authors
Introduction: Scientists use donated biospecimens to create organoids, which are miniature copies of patient tumors that are revolutionizing precision medicine and drug discovery. However, biobanking platforms remove donor identifiers to protect privacy, precluding patients from benefiting from their contributions or sharing information that may be relevant to research outcomes. Decentralized biobanking (de-bi) leverages blockchain technology to empower patient engagement in biospecimen research. We describe the creation of the first de-bi prototype for an organoid biobanking use case. Methods: We designed and developed a proof-of-concept non-fungible tokens (NFTs) framework for an organoid research network of patients, physicians, and scientists within a synthetic dataset modeled on a real-world breast cancer organoid ecosystem. Our implementation deployed multiple smart contracts on Ethereum test networks, minting NFTs representing each stakeholder, biospecimen, and organoid. The system architecture was designed to be composable with established biobanking programs. Results: Our de-bi prototype demonstrated how NFTs representing patients, physicians, scientists, and organoids may be united in a privacy-preserving platform that builds upon relationships and transactions of existing biobank research networks. The mobile application simulated key features, enabling patients to track their biospecimens, view organoid images and research updates from scientists, and allow physicians to participate in peer-to-peer communications with basic scientists and patients alike, all while ensuring compliance with de-identification requirements. Discussion: We demonstrate proof-of-concept for a web3 platform engaging patients, physicians, and scientists in a dynamic research community, unlocking value for a model organoid ecosystem. This initial prototype is a critical first step for advancing paradigm-shifting de-bi technology that provides unprecedented transparency and suggests new standards for equity and inclusion in biobanking. Further research must address feasibility and acceptability considering the ethical, legal, economic, and technical complexities of organoid research and clinical translation.
Chris Elsden, Evan Morgan, Ella Tallyn, Suzanne Black · 8 authors
This paper presents the design, deployment and qualitative study of a large-scale, public, generative art exhibition, through which passers-by could create artworks, and mint a non-fungible-token (NFT). Following the month-long exhibition, during which 229 anonymous participants produced artworks, 69 non-transferable NFTs were minted, we surveyed (33) and interviewed (14) expert and novice participants about their experiences. We explored contemporary challenges of owning digital things, and the extent to which NFTs, and 'Web3' technologies offer meaningful forms of ownership. Our findings describe how the inability to trade this NFT, and its unique circumstances of acquisition, made it meaningful in ways that extended beyond its immediate (limited) utility and offered participants something through which to construct identity. Reflecting on the aspirations, contradictions, and misconceptions of forms of ownership enabled by NFTs, we conclude with proposals for renewed attention in HCI to the nature of digital possessions, and the potential for 'ownership design'.
In this article, Erik Bordeleau presents, as a form of anarchic resistance to the capitalist logic, The Sphere project in which he is involved. For the author, The Sphere can be understood as a virtual space for exchanges between artistic processes and financing practices, whose root comes from a need to give new understanding to the meaning and use of digital media. He also states that the project is specifically interested in promoting the integration of creators, producers and the public, enabling an ecosystem that facilitates the alignment between interests and purposes through a spirit of speculative generosity. Therefore, the author uses reflections from renowned figures in the intellectual world, such as, for example, Deleuze and Guattari, Hito Steyerl, Jean-Luc Nancy, Jacques Rancière and Yuk Hui fundamentally to propose the defense of the need for a new look at crypto and blockchain technology, considering the decentralization provided by DAOs and Web3. Generating new forms of rhizomatic organization, instead of nostalgic notions of mass organization, ends up producing the possibility of codifying relations of equity through vectors of mutual participation.
This chapter explores the evolving legal context surrounding the ownership of digital assets, delving into the ramifications of legal frameworks such as property law, copyright, and data protection for the creative digital industry. We underline the importance of the nexus between ownership technology and legal reform, which will bear profound implications for the digital creative economy. Focusing on the recent consultation and recommendations by the Law Commission of England and Wales on this topic (2022–3), we suggest incremental legal adjustments as alternative strategies. We juxtapose this backdrop with a case study on non-fungible tokens (NFTs), which are envisioned as a “property layer” in the emerging Web3 Internet. The ascent of NFTs, evidenced by eye-catching transactions in the art world, underscores a paradigm shift in digital ownership. However, NFTs and decentralised technologies, while holding substantial promise, do not yet fully align with creatives’ desired rights. In order to provide legal certainty, we emphasise the need for nuanced understanding and collaboration among legal scholars, computer scientists, and creative industry stakeholders in order to reimagine property rights in the digital sphere, shaping the future of digital assets and their place within the creative economy together.
Web services that use a blockchain and crypto-assets (Web3 services) improve user privacy by anonymous logins using wallet addresses. However, since many users list their account identities (IDs) on social networking service (SNS) profile pages and reuse their account IDs for self-branding and curation purposes, which increases the risk of de-anonymization on Web3 services by linking these accounts. If such high-risk SNS accounts hold large amounts of crypto-assets, they are subject to account hijacking and spoofing attacks for financial gain. In this study, we proposed a method to discover highly relevant SNS accounts from a seed account on Web2 and Web3 SNSs and estimate their account ownership. We applied our method to 480 seed accounts of 9 different SNSs and discovered 1,233 new accounts. We found that SNSs with multiple URL input forms on their profile setting pages linked more accounts and revealed that 207 out of 253 (81.8%) users reused their IDs across different SNSs. We identified 26 accounts linked to personal and crypto-asset information that are at risk of de-anonymization. Our user study using crowdsourcing services showed that as many as 232 (40.8%) out of 568 respondents do not understand the traceability of blockchain transaction histories. We examined the security and privacy risks caused by account listing and ID reuse, and made recommendations for service providers and users based on our findings.