Pub Date : 2019-12-19DOI: 10.1109/ICBC48266.2020.9169456
Rene Pickhardt, M. Nowostawski
Making a payment in a privacy-aware payment channel network can be achieved by trying out several payment paths until one succeeds. With a large network, such as the Lightning Network, a completion of a single payment can take up to several minutes. We introduce a network imbalance measure and formulate the optimization problem of improving the balance of the network as a sequence of rebalancing operations of the funds within the channels along circular paths within the network. As the funds and balances of channels are not globally known, we introduce a greedy heuristic that improves every node’s local balance despite the uncertainty. In an empirical simulation on a snapshot of the Lightning Network we demonstrate that the imbalance distribution of the network has a Kolmogorov-Smirnoff distance of 0.74 in comparison to the imbalance distribution after the heuristic is applied. We further show that the success rate of a single unit payment increases from 11.2% on the imbalanced network to 98.3% in the balanced network. Similarly, the median possible payment size across all pairs of participants increases from 0 to 0.5 mBTC for initial routing attempts on the cheapest possible path. Executing 4 different strategies for selecting rebalancing cycles lead to similar results indicating that a collaborative approach within the friend of a friend network might be preferable from a practical point of view.1
{"title":"Imbalance measure and proactive channel rebalancing algorithm for the Lightning Network","authors":"Rene Pickhardt, M. Nowostawski","doi":"10.1109/ICBC48266.2020.9169456","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169456","url":null,"abstract":"Making a payment in a privacy-aware payment channel network can be achieved by trying out several payment paths until one succeeds. With a large network, such as the Lightning Network, a completion of a single payment can take up to several minutes. We introduce a network imbalance measure and formulate the optimization problem of improving the balance of the network as a sequence of rebalancing operations of the funds within the channels along circular paths within the network. As the funds and balances of channels are not globally known, we introduce a greedy heuristic that improves every node’s local balance despite the uncertainty. In an empirical simulation on a snapshot of the Lightning Network we demonstrate that the imbalance distribution of the network has a Kolmogorov-Smirnoff distance of 0.74 in comparison to the imbalance distribution after the heuristic is applied. We further show that the success rate of a single unit payment increases from 11.2% on the imbalanced network to 98.3% in the balanced network. Similarly, the median possible payment size across all pairs of participants increases from 0 to 0.5 mBTC for initial routing attempts on the cheapest possible path. Executing 4 different strategies for selecting rebalancing cycles lead to similar results indicating that a collaborative approach within the friend of a friend network might be preferable from a practical point of view.1","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123578788","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 : 2019-12-14DOI: 10.1109/ICBC48266.2020.9169398
T. Hardjono, A. Pentland
In order for VASPs to fulfill the regulatory requirements from the FATF and the Travel Rule, VASPs need truthful information regarding subjects, such as originators, beneficiaries and other VASPs involved in a virtual asset transfer. However, given that data about subjects are siloed in various organizations and institutions, there needs to be a practical way for VASPs to obtain information from these entities without direct access to the siloed data. In this paper we describe the Open Algorithms approach as a means for data holders to make insights about subjects available to Claims Providers based on vetted algorithms. A Claims Provider delivers signed claims to VASPs regarding the relevant subject, thereby relieving the VASP from having to deal with data, algorithms and analytics. We also propose a consortium arrangement for VASPs to establish a Claims Exchange Network, in which VASPs can deliver signed claims (obtained from their Claims Providers) and public-key information or certificates to other VASPs in a secure and confidential manner.
{"title":"Privacy-Preserving Claims Exchange Networks for Virtual Asset Service Providers","authors":"T. Hardjono, A. Pentland","doi":"10.1109/ICBC48266.2020.9169398","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169398","url":null,"abstract":"In order for VASPs to fulfill the regulatory requirements from the FATF and the Travel Rule, VASPs need truthful information regarding subjects, such as originators, beneficiaries and other VASPs involved in a virtual asset transfer. However, given that data about subjects are siloed in various organizations and institutions, there needs to be a practical way for VASPs to obtain information from these entities without direct access to the siloed data. In this paper we describe the Open Algorithms approach as a means for data holders to make insights about subjects available to Claims Providers based on vetted algorithms. A Claims Provider delivers signed claims to VASPs regarding the relevant subject, thereby relieving the VASP from having to deal with data, algorithms and analytics. We also propose a consortium arrangement for VASPs to establish a Claims Exchange Network, in which VASPs can deliver signed claims (obtained from their Claims Providers) and public-key information or certificates to other VASPs in a secure and confidential manner.","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126659499","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 : 2019-10-16DOI: 10.1109/ICBC48266.2020.9169432
R. Agarwal, Dhruv Kumar, Lukasz Golab, S. Keshav
The increasing amount of personal data is raising serious issues in the context of privacy, security, and data ownership. Entities whose data are being collected can benefit from mechanisms to manage the parties that can access their data and to audit who has accessed their data. Consent management systems address these issues. We present Consentio, a scalable consent management system based on the Hyperledger Fabric permissioned blockchain. The challenge we address is to ensure high throughput and low latency of endorsing data access requests and granting or revoking consent. Experimental results show that our system can handle as many as 6,000 access requests per second, allowing it to scale to very large deployments.
{"title":"Consentio: Managing Consent to Data Access using Permissioned Blockchains","authors":"R. Agarwal, Dhruv Kumar, Lukasz Golab, S. Keshav","doi":"10.1109/ICBC48266.2020.9169432","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169432","url":null,"abstract":"The increasing amount of personal data is raising serious issues in the context of privacy, security, and data ownership. Entities whose data are being collected can benefit from mechanisms to manage the parties that can access their data and to audit who has accessed their data. Consent management systems address these issues. We present Consentio, a scalable consent management system based on the Hyperledger Fabric permissioned blockchain. The challenge we address is to ensure high throughput and low latency of endorsing data access requests and granting or revoking consent. Experimental results show that our system can handle as many as 6,000 access requests per second, allowing it to scale to very large deployments.","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131510546","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 : 2019-07-21DOI: 10.1109/ICBC48266.2020.9169407
A. Mamageishvili, Jan Christoph Schlegel
We study optimal smart contract design for monitoring an exchange of an item performed offline. There are two parties, a seller and a buyer. Exchange happens off-chain, but the status update takes place on-chain. The exchange can be verified but with a cost. To guarantee self-enforcement of the smart contract, both parties make a deposit, and the deposits must cover payments made in all possible final states. Both parties have an (opportunity) cost of making deposits. We discuss two classes of contract: In the first, the mechanism only interacts with the seller, while in the second, the mechanism can also interact with the buyer. In both cases, we derive optimal contracts specifying optimal deposits and verification policies. The gains from trade of the first contract are dominated by the second contract, on the whole domain of parameters. However, the first type of contract has the advantage of less communication and, therefore, more flexibility.
{"title":"Optimal Smart Contracts with Costly Verification","authors":"A. Mamageishvili, Jan Christoph Schlegel","doi":"10.1109/ICBC48266.2020.9169407","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169407","url":null,"abstract":"We study optimal smart contract design for monitoring an exchange of an item performed offline. There are two parties, a seller and a buyer. Exchange happens off-chain, but the status update takes place on-chain. The exchange can be verified but with a cost. To guarantee self-enforcement of the smart contract, both parties make a deposit, and the deposits must cover payments made in all possible final states. Both parties have an (opportunity) cost of making deposits. We discuss two classes of contract: In the first, the mechanism only interacts with the seller, while in the second, the mechanism can also interact with the buyer. In both cases, we derive optimal contracts specifying optimal deposits and verification policies. The gains from trade of the first contract are dominated by the second contract, on the whole domain of parameters. However, the first type of contract has the advantage of less communication and, therefore, more flexibility.","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123476555","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 : 2019-06-26DOI: 10.1109/ICBC48266.2020.9169478
Christian Gorenflo, Lukasz Golab, S. Keshav
Performance and scalability are major concerns for blockchains: permissionless systems are typically limited by slow proof of X consensus algorithms and sequential postorder transaction execution on every node of the network. By introducing a small amount of trust in their participants, permissioned blockchain systems such as Hyperledger Fabric can benefit from more efficient consensus algorithms and make use of parallel pre-order execution on a subset of network nodes. Fabric, in particular, has been shown to handle tens of thousands of transactions per second. However, this performance is only achievable for contention-free transaction workloads. If many transactions compete for a small set of hot keys in the world state, the effective throughput drops drastically. We therefore propose XOX: a novel two-pronged transaction execution approach that both minimizes invalid transactions in the Fabric blockchain and maximizes concurrent execution. Our approach additionally prevents unintentional denial of service attacks by clients resubmitting conflicting transactions. Even under fully contentious workloads, XOX can handle more than 3000 transactions per second, all of which would be discarded by regular Fabric.
{"title":"XOX Fabric: A hybrid approach to blockchain transaction execution","authors":"Christian Gorenflo, Lukasz Golab, S. Keshav","doi":"10.1109/ICBC48266.2020.9169478","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169478","url":null,"abstract":"Performance and scalability are major concerns for blockchains: permissionless systems are typically limited by slow proof of X consensus algorithms and sequential postorder transaction execution on every node of the network. By introducing a small amount of trust in their participants, permissioned blockchain systems such as Hyperledger Fabric can benefit from more efficient consensus algorithms and make use of parallel pre-order execution on a subset of network nodes. Fabric, in particular, has been shown to handle tens of thousands of transactions per second. However, this performance is only achievable for contention-free transaction workloads. If many transactions compete for a small set of hot keys in the world state, the effective throughput drops drastically. We therefore propose XOX: a novel two-pronged transaction execution approach that both minimizes invalid transactions in the Fabric blockchain and maximizes concurrent execution. Our approach additionally prevents unintentional denial of service attacks by clients resubmitting conflicting transactions. Even under fully contentious workloads, XOX can handle more than 3000 transactions per second, all of which would be discarded by regular Fabric.","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116498687","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 : 2019-05-23DOI: 10.1109/ICBC48266.2020.9169394
Hao Hao Tan
All-to-all data transmission is a typical data transmission pattern in both consensus protocols and blockchain systems. Developing an optimization scheme that provides high throughput and low latency data transmission can significantly benefit the performance of those systems. This paper investigates the problem of optimizing all-to-all data transmission in a wide area network (WAN) using overlay multicast. We prove that in a hose network model, using shallow tree overlays with height up to two is sufficient for all-to-all data transmission to achieve the optimal throughput allowed by the available network resources. Upon this foundation, we build ShallowForest, a data plane optimization for consensus protocols and blockchain systems. The goal of ShallowForest is to improve consensus protocols’ resilience to skewed client load distribution. Experiments with skewed client load across replicas in the Amazon cloud demonstrate that ShallowForest can improve the commit throughput of the EPaxos consensus protocol by up to 100% with up to 60% reduction in commit latency.
{"title":"Optimizing All-to-All Data Transmission in WANs","authors":"Hao Hao Tan","doi":"10.1109/ICBC48266.2020.9169394","DOIUrl":"https://doi.org/10.1109/ICBC48266.2020.9169394","url":null,"abstract":"All-to-all data transmission is a typical data transmission pattern in both consensus protocols and blockchain systems. Developing an optimization scheme that provides high throughput and low latency data transmission can significantly benefit the performance of those systems. This paper investigates the problem of optimizing all-to-all data transmission in a wide area network (WAN) using overlay multicast. We prove that in a hose network model, using shallow tree overlays with height up to two is sufficient for all-to-all data transmission to achieve the optimal throughput allowed by the available network resources. Upon this foundation, we build ShallowForest, a data plane optimization for consensus protocols and blockchain systems. The goal of ShallowForest is to improve consensus protocols’ resilience to skewed client load distribution. Experiments with skewed client load across replicas in the Amazon cloud demonstrate that ShallowForest can improve the commit throughput of the EPaxos consensus protocol by up to 100% with up to 60% reduction in commit latency.","PeriodicalId":420845,"journal":{"name":"2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121977368","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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