Pub Date : 2019-07-01DOI: 10.1109/blockchain.2019.00009
D. Niyato, Peter Müller, Z. Cai, Sachiko Yoshihama, Victor C. M. Leung, W. Lou, Chonggang Wang, Xueqin Liang, Wei Li, Dan Lo, Albert Cabellos-Aparicio, A. Sorniotti, D. Hogrefe, Dilip Krishnaswamy, Elena Ferrari, Fei Chen, F. Kargl, G. Piliouras
Steering Committee Elisa Bertino, Purdue University, USA Jinjun Chen, Swinburne University of Technology, Australia Robert H. Deng, Singapore Management University, Singapore Victor C. M. Leung, University of British Columbia, Canada Fenghua Li, Chinese Academy of Sciences, China Wenjing Lou, Virginia Polytechnic Institute and State University, USA Vijay Varadharajan, University of Newcastle, Australia Chonggang Wang, InterDigital, USA Yang Xiang, Swinburne University of Technology, Australia Zheng Yan (Chair), Xidian University, China and Aalto University, Finland Laurence T. Yang (Chair), St. Francis Xavier University, Canada Qinghua Zheng, Xi’an Jiaotong University, China Pierangela Samarati, Università degli Studi di Milano, Italy
指导委员会Elisa Bertino，普渡大学，美国陈劲军，斯威本科技大学，澳大利亚Robert H. Deng，新加坡管理大学，新加坡Victor C. M. Leung，加拿大英属哥伦比亚大学，加拿大李凤华，中国科学院，中国楼文静，弗吉尼亚理工学院和州立大学，美国Vijay Varadharajan，纽卡斯尔大学，澳大利亚王崇刚，InterDigital，美国向阳，斯威本科技大学，澳大利亚郑岩(主席)，中国西安电子科技大学，芬兰阿尔托大学，Laurence T. Yang(主席)，加拿大圣弗朗西斯泽维尔大学，中国西安交通大学郑清华，意大利米兰理工大学Pierangela Samarati
{"title":"Blockchain 2019 Organizing and Program Committees","authors":"D. Niyato, Peter Müller, Z. Cai, Sachiko Yoshihama, Victor C. M. Leung, W. Lou, Chonggang Wang, Xueqin Liang, Wei Li, Dan Lo, Albert Cabellos-Aparicio, A. Sorniotti, D. Hogrefe, Dilip Krishnaswamy, Elena Ferrari, Fei Chen, F. Kargl, G. Piliouras","doi":"10.1109/blockchain.2019.00009","DOIUrl":"https://doi.org/10.1109/blockchain.2019.00009","url":null,"abstract":"Steering Committee Elisa Bertino, Purdue University, USA Jinjun Chen, Swinburne University of Technology, Australia Robert H. Deng, Singapore Management University, Singapore Victor C. M. Leung, University of British Columbia, Canada Fenghua Li, Chinese Academy of Sciences, China Wenjing Lou, Virginia Polytechnic Institute and State University, USA Vijay Varadharajan, University of Newcastle, Australia Chonggang Wang, InterDigital, USA Yang Xiang, Swinburne University of Technology, Australia Zheng Yan (Chair), Xidian University, China and Aalto University, Finland Laurence T. Yang (Chair), St. Francis Xavier University, Canada Qinghua Zheng, Xi’an Jiaotong University, China Pierangela Samarati, Università degli Studi di Milano, Italy","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116698030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/blockchain.2019.00007
IEEE Blockchain 2019 conference is the second edition of the highly successful International Conference on Blockchain (Blockchain). It provides a forum for engineers and scientists in academia, industry, and government to address the resulting profound challenges and to present and discuss their new ideas, research results, applications and experience on all aspects of blockchain. IEEE Blockchain 2019 is sponsored by IEEE, IEEE Computer Society, IEEE Technical Committee on Scalable Computing (TCSC) and IEEE Future Direction Committee.
{"title":"Message from the Blockchain 2019 General Chairs","authors":"","doi":"10.1109/blockchain.2019.00007","DOIUrl":"https://doi.org/10.1109/blockchain.2019.00007","url":null,"abstract":"IEEE Blockchain 2019 conference is the second edition of the highly successful International Conference on Blockchain (Blockchain). It provides a forum for engineers and scientists in academia, industry, and government to address the resulting profound challenges and to present and discuss their new ideas, research results, applications and experience on all aspects of blockchain. IEEE Blockchain 2019 is sponsored by IEEE, IEEE Computer Society, IEEE Technical Committee on Scalable Computing (TCSC) and IEEE Future Direction Committee.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127526888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00020
Z. Wan, Zhangshuang Guan, Yan Zhou, K. Ren
The emerging blockchain technology, powered by the smart contract functionality, is expected to revolutionize traditional systems by decentralization and autonomy. When the blockchain technology is applied in real-life systems, a smart contract may need to take in sensitive data to execute its code. For example, a decentralized medical insurance smart contract needs access to personal health data. Therefore, it is crucial to guarantee both privacy and authenticity of data sent to the smart contract, so that everyone can verify data without leaking sensitive information. Currently, only few works have tried to achieve privacy and authenticity at the same time. In this work, we first propose zk-DASNARK, a zero-knowledge SNARK scheme for authenticated data. It is designed by combining the zk-SNARK technique with digital signature in an effective way. Based on zk-DASNARK, we design zk-AuthFeed, a zero-knowledge authenticated data feed scheme to achieve both data privacy and authenticity for smart contract. We implement zk-AuthFeed and conduct comprehensive experiments on Ethereum. The experiments show that zk-AuthFeed is highly efficient: key generation takes about 7 seconds only, proof generation takes less than 2 seconds, and proof verification takes less than 40 ms.
{"title":"zk-AuthFeed: How to Feed Authenticated Data into Smart Contract with Zero Knowledge","authors":"Z. Wan, Zhangshuang Guan, Yan Zhou, K. Ren","doi":"10.1109/Blockchain.2019.00020","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00020","url":null,"abstract":"The emerging blockchain technology, powered by the smart contract functionality, is expected to revolutionize traditional systems by decentralization and autonomy. When the blockchain technology is applied in real-life systems, a smart contract may need to take in sensitive data to execute its code. For example, a decentralized medical insurance smart contract needs access to personal health data. Therefore, it is crucial to guarantee both privacy and authenticity of data sent to the smart contract, so that everyone can verify data without leaking sensitive information. Currently, only few works have tried to achieve privacy and authenticity at the same time. In this work, we first propose zk-DASNARK, a zero-knowledge SNARK scheme for authenticated data. It is designed by combining the zk-SNARK technique with digital signature in an effective way. Based on zk-DASNARK, we design zk-AuthFeed, a zero-knowledge authenticated data feed scheme to achieve both data privacy and authenticity for smart contract. We implement zk-AuthFeed and conduct comprehensive experiments on Ethereum. The experiments show that zk-AuthFeed is highly efficient: key generation takes about 7 seconds only, proof generation takes less than 2 seconds, and proof verification takes less than 40 ms.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124934813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00002
S. Latifi, Yunpeng Zhang, Liang-Chieh Cheng
Global real estate (RE) investments account more than twice the size of the stock market. Yet the number of investors in RE are much lower, because of the liquidity and global access. Tenants, owners, and investors are barely satisfied in the current system. In this paper, the goal is to try out the employment of blockchain in RE market and represent the facilities it can give to the RE market. The research to date leads to the following conclusions: Blockchain technology and smart contracts can sort out the classical issues that RE is facing with, and they offer much more meaningful tools for a game theoretic stable-priced market.
{"title":"Blockchain-Based Real Estate Market: One Method for Applying Blockchain Technology in Commercial Real Estate Market","authors":"S. Latifi, Yunpeng Zhang, Liang-Chieh Cheng","doi":"10.1109/Blockchain.2019.00002","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00002","url":null,"abstract":"Global real estate (RE) investments account more than twice the size of the stock market. Yet the number of investors in RE are much lower, because of the liquidity and global access. Tenants, owners, and investors are barely satisfied in the current system. In this paper, the goal is to try out the employment of blockchain in RE market and represent the facilities it can give to the RE market. The research to date leads to the following conclusions: Blockchain technology and smart contracts can sort out the classical issues that RE is facing with, and they offer much more meaningful tools for a game theoretic stable-priced market.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116519066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00012
Emmanuel Nyaletey, R. Parizi, Qi Zhang, Kim-Kwang Raymond Choo
The Interplanetary File System (IPFS) is a distributed file system that seeks to decentralize the web and to make it faster and more efficient. It incorporates well-known technologies, including BitTorrent and Git, to create a swarm of computing systems that share information. Since its introduction in 2016, IPFS has seen great improvements and adoption from both individuals and enterprise organizations. Its distributed network allows users to share files and information across the globe. IPFS works well with large files that may consume or require large bandwidth to upload and/or download over the Internet. The rapid adoption of this distributed file system is in part because IPFS is designed to operate on top of different protocols, such as FTP and HTTP. However, there are underpinning concerns relating to security and access control, for example lack of traceability on how the files are accessed. The aim of this paper is to complement IPFS with blockchain technology, by proposing a new approach (BlockIPFS) to create a clear audit trail. BlockIPFS allows us to achieve improved trustworthiness of the data and authorship protection, and provide a clear route to trace back all activities associated with a given file using blockchain as a service.
{"title":"BlockIPFS - Blockchain-Enabled Interplanetary File System for Forensic and Trusted Data Traceability","authors":"Emmanuel Nyaletey, R. Parizi, Qi Zhang, Kim-Kwang Raymond Choo","doi":"10.1109/Blockchain.2019.00012","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00012","url":null,"abstract":"The Interplanetary File System (IPFS) is a distributed file system that seeks to decentralize the web and to make it faster and more efficient. It incorporates well-known technologies, including BitTorrent and Git, to create a swarm of computing systems that share information. Since its introduction in 2016, IPFS has seen great improvements and adoption from both individuals and enterprise organizations. Its distributed network allows users to share files and information across the globe. IPFS works well with large files that may consume or require large bandwidth to upload and/or download over the Internet. The rapid adoption of this distributed file system is in part because IPFS is designed to operate on top of different protocols, such as FTP and HTTP. However, there are underpinning concerns relating to security and access control, for example lack of traceability on how the files are accessed. The aim of this paper is to complement IPFS with blockchain technology, by proposing a new approach (BlockIPFS) to create a clear audit trail. BlockIPFS allows us to achieve improved trustworthiness of the data and authorship protection, and provide a clear route to trace back all activities associated with a given file using blockchain as a service.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134410292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00013
Saide Zhu, Huafu Hu, Yingshu Li, Wei Li
Blockchain has been treated as one of the most promising technologies to promote crowdsourcing by providing new nice features, such as decentralization and accountability. Unfortunately, some inherent limitations of blockchain have been rarely addressed by the most existing works when applying blockchain into crowdsourcing, which becomes the performance bottleneck of crowdsourcing systems. In this paper, we propose a novel hybrid blockchain crowdsourcing platform to achieve decentralization and privacy preservation. Our platform integrates with a hybrid blockchain structure, dual-ledgers, and dual consensus algorithms to ensure secure communication between the requesters and the workers. Moreover, the smart contract and zero-knowledge proof are employed to ensure automatic operation of the tasks and the protection users' privacy, respectively. Finally, we conduct experiments to confirm the efficiency of the adopted consensus algorithm on our platform by comparing it with the state-of-the-art.
{"title":"Hybrid Blockchain Design for Privacy Preserving Crowdsourcing Platform","authors":"Saide Zhu, Huafu Hu, Yingshu Li, Wei Li","doi":"10.1109/Blockchain.2019.00013","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00013","url":null,"abstract":"Blockchain has been treated as one of the most promising technologies to promote crowdsourcing by providing new nice features, such as decentralization and accountability. Unfortunately, some inherent limitations of blockchain have been rarely addressed by the most existing works when applying blockchain into crowdsourcing, which becomes the performance bottleneck of crowdsourcing systems. In this paper, we propose a novel hybrid blockchain crowdsourcing platform to achieve decentralization and privacy preservation. Our platform integrates with a hybrid blockchain structure, dual-ledgers, and dual consensus algorithms to ensure secure communication between the requesters and the workers. Moreover, the smart contract and zero-knowledge proof are employed to ensure automatic operation of the tasks and the protection users' privacy, respectively. Finally, we conduct experiments to confirm the efficiency of the adopted consensus algorithm on our platform by comparing it with the state-of-the-art.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114591593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00004
A. Davenport, S. Shetty
In this paper we consider the threat surface and security of air gapped wallet schemes for permissioned blockchains as preparation for a Markov based mathematical model, and quantify the risk associated with private key leakage. We identify existing threats to the wallet scheme and existing work done to both attack and secure the scheme. We provide an overview the proposed model and outline justification for our methods. We follow with next steps in our remaining work and the overarching goals and motivation for our methods.
{"title":"Air Gapped Wallet Schemes and Private Key Leakage in Permissioned Blockchain Platforms","authors":"A. Davenport, S. Shetty","doi":"10.1109/Blockchain.2019.00004","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00004","url":null,"abstract":"In this paper we consider the threat surface and security of air gapped wallet schemes for permissioned blockchains as preparation for a Markov based mathematical model, and quantify the risk associated with private key leakage. We identify existing threats to the wallet scheme and existing work done to both attack and secure the scheme. We provide an overview the proposed model and outline justification for our methods. We follow with next steps in our remaining work and the overarching goals and motivation for our methods.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"193 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122127627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00033
Luming Wan, D. Eyers, Haibo Zhang
Blockchain came to prominence as the distributed ledger underneath Bitcoin, which protects the transaction histories in a fully-connected, peer-to-peer network. For safety against double-spending, a bitcoin transaction is only considered to be unrevokable after it is within a chain of at least six mined blocks on the blockchain-termed "six confirmations" for short. Besides the use for securing financial activity, blockchain technology is now also merged with various emerging applications, including Internet of Things (IoT) and vehicular ad-hoc networks (VANET). However, such emerging applications may have comparatively low Internet connectivity due to incorporating mobile devices, that may range away from network infrastructure. This paper investigates the impact of network latency on blockchain forking behavior and possible violations of the aforementioned six confirmations convention for transaction approval. To speed up our simulations, we simplify the lockchain's data structure, and avoid the extensive computation required in proof-of-work (PoW). Through simulation, we show that the six confirmations convention is sensitive to the peer-to-peer network latency, and also show how quickly it is violated with an easier difficulty of PoW mining. Unsurprisingly, the speed at which all nodes on the blockchain converge is shown to be severely affected by the latency of the underlying peer-to-peer network. It is also shown the extent to which nodes with more frequent Internet connectivity can gain an unfair advantage in terms of proof-ofwork mining rewards. We thus recommend that networks with heterogeneous latency profiles across nodes monitor fairness, and potentially preclude some nodes from being miners.
{"title":"Evaluating the Impact of Network Latency on the Safety of Blockchain Transactions","authors":"Luming Wan, D. Eyers, Haibo Zhang","doi":"10.1109/Blockchain.2019.00033","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00033","url":null,"abstract":"Blockchain came to prominence as the distributed ledger underneath Bitcoin, which protects the transaction histories in a fully-connected, peer-to-peer network. For safety against double-spending, a bitcoin transaction is only considered to be unrevokable after it is within a chain of at least six mined blocks on the blockchain-termed \"six confirmations\" for short. Besides the use for securing financial activity, blockchain technology is now also merged with various emerging applications, including Internet of Things (IoT) and vehicular ad-hoc networks (VANET). However, such emerging applications may have comparatively low Internet connectivity due to incorporating mobile devices, that may range away from network infrastructure. This paper investigates the impact of network latency on blockchain forking behavior and possible violations of the aforementioned six confirmations convention for transaction approval. To speed up our simulations, we simplify the lockchain's data structure, and avoid the extensive computation required in proof-of-work (PoW). Through simulation, we show that the six confirmations convention is sensitive to the peer-to-peer network latency, and also show how quickly it is violated with an easier difficulty of PoW mining. Unsurprisingly, the speed at which all nodes on the blockchain converge is shown to be severely affected by the latency of the underlying peer-to-peer network. It is also shown the extent to which nodes with more frequent Internet connectivity can gain an unfair advantage in terms of proof-ofwork mining rewards. We thus recommend that networks with heterogeneous latency profiles across nodes monitor fairness, and potentially preclude some nodes from being miners.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125418783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00024
Saulo dos Santos, Chukwuka Chukwuocha, Shahin Kamali, R. Thulasiram
Cryptocurrencies like Bitcoin use the blockchain technology to record transactions in a distributed and secure way. Each block contains a cryptographic hash of the previous block in addition to a set of transactions that it records. The first step for a miner to add a new block to the blockchain is to select a set of pending transactions from a mempool. The total size of selected transactions should not exceed the fixed capacity of blocks. If a miner completes the computationally-hard task of finding the cryptographic hash of the formed block, the block can be added to the blockchain in which case the transactions in that block will become complete. Transaction might have a fee that is granted to the miner upon being complete. As such, when forming a new block, miners tend to select transactions that offer the best fees. Finding a set of transactions with maximum total fee that fit into a block translates to the classic knapsack problem, which is an NP-hard problem. Meanwhile, miners are in fierce competition for mining blocks and hence cannot dedicate too much computational power for selecting the best set of transactions. Most existing solutions to tackle this problem are based on sorting the set of pending transactions by the ratio between their fee and their size. While the sorting step is not a bottleneck in normal situations, transaction can grow explosively in case of a market turbulence like that of 2017. Meanwhile, the total number of transactions increases over time. As such, it is desirable to have an efficient strategy that does not rely on sorting transactions before forming a block. In this paper, we review some of the existing strategies for miners to select transactions from the mempool. We also introduce a robust solution called Size-Density Table (SDT) for selecting transactions that does not use sorting. We perform a theoretical and experimental analysis of our solutions to compare it with other strategies. Our results indicate that our algorithm runs faster than previous approaches while the quality of its solutions (the total fees collected in its blocks) is also slightly better than the best existing strategies.
{"title":"An Efficient Miner Strategy for Selecting Cryptocurrency Transactions","authors":"Saulo dos Santos, Chukwuka Chukwuocha, Shahin Kamali, R. Thulasiram","doi":"10.1109/Blockchain.2019.00024","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00024","url":null,"abstract":"Cryptocurrencies like Bitcoin use the blockchain technology to record transactions in a distributed and secure way. Each block contains a cryptographic hash of the previous block in addition to a set of transactions that it records. The first step for a miner to add a new block to the blockchain is to select a set of pending transactions from a mempool. The total size of selected transactions should not exceed the fixed capacity of blocks. If a miner completes the computationally-hard task of finding the cryptographic hash of the formed block, the block can be added to the blockchain in which case the transactions in that block will become complete. Transaction might have a fee that is granted to the miner upon being complete. As such, when forming a new block, miners tend to select transactions that offer the best fees. Finding a set of transactions with maximum total fee that fit into a block translates to the classic knapsack problem, which is an NP-hard problem. Meanwhile, miners are in fierce competition for mining blocks and hence cannot dedicate too much computational power for selecting the best set of transactions. Most existing solutions to tackle this problem are based on sorting the set of pending transactions by the ratio between their fee and their size. While the sorting step is not a bottleneck in normal situations, transaction can grow explosively in case of a market turbulence like that of 2017. Meanwhile, the total number of transactions increases over time. As such, it is desirable to have an efficient strategy that does not rely on sorting transactions before forming a block. In this paper, we review some of the existing strategies for miners to select transactions from the mempool. We also introduce a robust solution called Size-Density Table (SDT) for selecting transactions that does not use sorting. We perform a theoretical and experimental analysis of our solutions to compare it with other strategies. Our results indicate that our algorithm runs faster than previous approaches while the quality of its solutions (the total fees collected in its blocks) is also slightly better than the best existing strategies.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122417580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/Blockchain.2019.00074
L. Lu, Jianhai Chen, Zijun Tian, Qinming He, Butian Huang, Yang Xiang, Zhenguang Liu
Nowadays, the rise in popularity of massive open online courses (MOOCs) is significant. However, current online education service heavily relies on a third-party platform, which acts as a middleman to process transactions occurred among system participants. On the one hand, this centralized business model is based on database management system, once compromised, the data consistency and safety of transaction records can no longer be guaranteed. On the other hand, it's more expensive to resolve disputes and possible fraud transactions via a mediator than a direct peer-to-peer trusted payment. Aiming at solving issues regarding security and inefficiencies, we propose a crypto-asset EduCoin which is designed for secure and efficient payment in MOOC environment. Specially, we present a multi-party business model based on permissioned blockchain, Composer smart contracts and network topologies that utilize the three-tiered functional architecture of Fabric to achieve fast payment and trusted audit. By leveraging benchmark tools Caliper and Hitchhiker, we develop typical workloads based on transaction scenarios applying EduCoin. The experimental results demonstrate the practicality of EduCoin and offer insights into the design trade-offs and performance bottlenecks in production. We have released EduCoin for public use.
{"title":"EduCoin: a Secure and Efficient Payment Solution for MOOC Environment","authors":"L. Lu, Jianhai Chen, Zijun Tian, Qinming He, Butian Huang, Yang Xiang, Zhenguang Liu","doi":"10.1109/Blockchain.2019.00074","DOIUrl":"https://doi.org/10.1109/Blockchain.2019.00074","url":null,"abstract":"Nowadays, the rise in popularity of massive open online courses (MOOCs) is significant. However, current online education service heavily relies on a third-party platform, which acts as a middleman to process transactions occurred among system participants. On the one hand, this centralized business model is based on database management system, once compromised, the data consistency and safety of transaction records can no longer be guaranteed. On the other hand, it's more expensive to resolve disputes and possible fraud transactions via a mediator than a direct peer-to-peer trusted payment. Aiming at solving issues regarding security and inefficiencies, we propose a crypto-asset EduCoin which is designed for secure and efficient payment in MOOC environment. Specially, we present a multi-party business model based on permissioned blockchain, Composer smart contracts and network topologies that utilize the three-tiered functional architecture of Fabric to achieve fast payment and trusted audit. By leveraging benchmark tools Caliper and Hitchhiker, we develop typical workloads based on transaction scenarios applying EduCoin. The experimental results demonstrate the practicality of EduCoin and offer insights into the design trade-offs and performance bottlenecks in production. We have released EduCoin for public use.","PeriodicalId":221068,"journal":{"name":"2019 IEEE International Conference on Blockchain (Blockchain)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127626088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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