Pub Date : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350834
Lei Lei, Ping Ma, C. Lan, L. Lin
VSS (Verifiable Secret Sharing) protocols are used in a number of block-chain systems, such as Dfinity and Ouroboros to generate unpredicted random number flow, they can be used to determine the proposer list and the voting powers of the voters at each height. To prevent random numbers from being predicted and attackers from corrupting a sufficient number of participants to violate the underlying trust assumptions, updatable VSS protocol in distributed protocols is important. The updatable VSS universal setup is also a hot topic in zkSNARKS protocols such as Sonic [19]. The way that we make it updatable is to execute the share exchange process repeatedly on chain, this process is challenging to be implemented in asynchronous network model, because it involves the wrong shares and the complaints, it requires the participant has the same view towards the qualified key generators, we take this process on chain and rely on BFT consensus mechanism to solve this. The group secret is thus updatable on chain. This is an enhancement to Dfinity. Therefore, even if all the coefficients of the random polynomials of epoch n are leaked, the attacker can use them only in epoch n+2. And the threshold group members of the DKG protocol can be updated along with the updates of the staked accounts and nodes.
{"title":"Continuous Distributed Key Generation on Blockchain Based on BFT Consensus","authors":"Lei Lei, Ping Ma, C. Lan, L. Lin","doi":"10.1109/HotICN50779.2020.9350834","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350834","url":null,"abstract":"VSS (Verifiable Secret Sharing) protocols are used in a number of block-chain systems, such as Dfinity and Ouroboros to generate unpredicted random number flow, they can be used to determine the proposer list and the voting powers of the voters at each height. To prevent random numbers from being predicted and attackers from corrupting a sufficient number of participants to violate the underlying trust assumptions, updatable VSS protocol in distributed protocols is important. The updatable VSS universal setup is also a hot topic in zkSNARKS protocols such as Sonic [19]. The way that we make it updatable is to execute the share exchange process repeatedly on chain, this process is challenging to be implemented in asynchronous network model, because it involves the wrong shares and the complaints, it requires the participant has the same view towards the qualified key generators, we take this process on chain and rely on BFT consensus mechanism to solve this. The group secret is thus updatable on chain. This is an enhancement to Dfinity. Therefore, even if all the coefficients of the random polynomials of epoch n are leaked, the attacker can use them only in epoch n+2. And the threshold group members of the DKG protocol can be updated along with the updates of the staked accounts and nodes.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123043435","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350856
Afnan M. Alniamy, Hang Liu
Research teams or institutions in different countries need an effective and secure online platform for collaboration and data sharing. It is essential to build such a collaboration platform with strong data security and privacy. In this paper, we propose a platform for researchers to collaborate and share their data by leveraging attribute-based access control (ABAC) and blockchain technologies. ABAC provides an access control paradigm whereby access rights are granted to users through attribute-based policies, instead of user identities and roles. Hyperledger fabric permission blockchain is used to enable a decentralized secure data sharing environment and preserves user’s privacy. The proposed platform allows researchers to fully control their data, manage access to the data at a fine-grained level, keep file updates with proof of authorship, and ensure data integrity and privacy.
{"title":"Blockchain-Based Secure Collaboration Platform for Sharing and Accessing Scientific Research Data","authors":"Afnan M. Alniamy, Hang Liu","doi":"10.1109/HotICN50779.2020.9350856","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350856","url":null,"abstract":"Research teams or institutions in different countries need an effective and secure online platform for collaboration and data sharing. It is essential to build such a collaboration platform with strong data security and privacy. In this paper, we propose a platform for researchers to collaborate and share their data by leveraging attribute-based access control (ABAC) and blockchain technologies. ABAC provides an access control paradigm whereby access rights are granted to users through attribute-based policies, instead of user identities and roles. Hyperledger fabric permission blockchain is used to enable a decentralized secure data sharing environment and preserves user’s privacy. The proposed platform allows researchers to fully control their data, manage access to the data at a fine-grained level, keep file updates with proof of authorship, and ensure data integrity and privacy.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127098239","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350830
Lin Yao, Z. Li, Wenyu Peng, Bin Wu, Weifeng Sun
Vehicular Content Centric Network (VCCN) enjoys advantages in effectiveness and convenience for content distribu- tion among vehicles, by adopting features of Content Centric Net- works into Vehicular Ad-Hoc Networks. However, the dynamic topology makes it difficult to establish stable connections. To get a better network performance and user experience, we exploit the user mobility to achieve efficient content distribution in VCCN. In this paper, we propose a mechanism for pre-caching chunks of large content objects such as videos among RSUs. First, we adopt Hidden Markov Model (HMM) to predict a user’ s moving trajectory. Based on the time gap from the current location to the predicted location of the mobile user, the corresponding RSU can pre-cache the required video chunks and provide them to the user as soon as he arrives at the predicted location. Simulation results show that our scheme is effective with higher cache hit, lower deliver latency, lower deliver overhead and lower average hops compared to other pre-caching schemes.
{"title":"A Pre-caching Mechanism of Video Stream Based on Hidden Markov Model in Vehicular Content Centric Network","authors":"Lin Yao, Z. Li, Wenyu Peng, Bin Wu, Weifeng Sun","doi":"10.1109/HotICN50779.2020.9350830","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350830","url":null,"abstract":"Vehicular Content Centric Network (VCCN) enjoys advantages in effectiveness and convenience for content distribu- tion among vehicles, by adopting features of Content Centric Net- works into Vehicular Ad-Hoc Networks. However, the dynamic topology makes it difficult to establish stable connections. To get a better network performance and user experience, we exploit the user mobility to achieve efficient content distribution in VCCN. In this paper, we propose a mechanism for pre-caching chunks of large content objects such as videos among RSUs. First, we adopt Hidden Markov Model (HMM) to predict a user’ s moving trajectory. Based on the time gap from the current location to the predicted location of the mobile user, the corresponding RSU can pre-cache the required video chunks and provide them to the user as soon as he arrives at the predicted location. Simulation results show that our scheme is effective with higher cache hit, lower deliver latency, lower deliver overhead and lower average hops compared to other pre-caching schemes.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123724587","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 : 2020-12-12DOI: 10.1109/hoticn50779.2020.9350783
{"title":"HotICN 2020 Table of Contents","authors":"","doi":"10.1109/hoticn50779.2020.9350783","DOIUrl":"https://doi.org/10.1109/hoticn50779.2020.9350783","url":null,"abstract":"","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"186 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125168400","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350821
Bing Li, M. Ma, Rong Xia
Named Data Networking (NDN) with the data-centric design has been viewed as a promising future Internet architecture. It requires a new security model orienting data but not host. In this paper, a Hierarchical Identity-based Security Mechanism by Blockchain (HISM-B) is to be proposed for NDN networks. It could satisfy the two assumptions specified in the NDN testbed to maintain the data-oriented authentication. At one hand, the hierarchical identity-based cryptology is used to bind the data name with the public key and then two signatures are encapsulated in the data packet so that the data source authentication and the integrity of data packet can be supported. At the other hand, a blockchain is employed to manage public keys for different domains to avoid catastrophes due to a single node failure. The validation result shows that the proposed HISM-B is safe.
{"title":"Hierarchical Identity-Based Security Mechanism Using Blockchain in Named Data Networking","authors":"Bing Li, M. Ma, Rong Xia","doi":"10.1109/HotICN50779.2020.9350821","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350821","url":null,"abstract":"Named Data Networking (NDN) with the data-centric design has been viewed as a promising future Internet architecture. It requires a new security model orienting data but not host. In this paper, a Hierarchical Identity-based Security Mechanism by Blockchain (HISM-B) is to be proposed for NDN networks. It could satisfy the two assumptions specified in the NDN testbed to maintain the data-oriented authentication. At one hand, the hierarchical identity-based cryptology is used to bind the data name with the public key and then two signatures are encapsulated in the data packet so that the data source authentication and the integrity of data packet can be supported. At the other hand, a blockchain is employed to manage public keys for different domains to avoid catastrophes due to a single node failure. The validation result shows that the proposed HISM-B is safe.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121080525","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350757
Quan Zheng, Yulin Bao, Zixuan Gao, Liu Yuan, Jian Yang, Xiaobin Tan
Most research on NDMANET cache strategy does not take the priority of content into consideration, which will affect the usability of important content in the mobile environment. Aiming at solving this problem, this paper proposes a cache replacement strategy based on content priority. First, the content is prioritized according to the different needs for the availability of different content. Then, the priority of the content is used as a reference factor for cache replacement to make a cache replacement decision, and the goal is to improve the hit rate and availability of important content. At the same time, the simulation results of ndnSIM show that the strategy can significantly increase the number of cached important content without affecting the global hit rate and response delay, thereby improving the availability of important content.
{"title":"Research on Content Priority-Based Caching Strategy in NDMANET","authors":"Quan Zheng, Yulin Bao, Zixuan Gao, Liu Yuan, Jian Yang, Xiaobin Tan","doi":"10.1109/HotICN50779.2020.9350757","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350757","url":null,"abstract":"Most research on NDMANET cache strategy does not take the priority of content into consideration, which will affect the usability of important content in the mobile environment. Aiming at solving this problem, this paper proposes a cache replacement strategy based on content priority. First, the content is prioritized according to the different needs for the availability of different content. Then, the priority of the content is used as a reference factor for cache replacement to make a cache replacement decision, and the goal is to improve the hit rate and availability of important content. At the same time, the simulation results of ndnSIM show that the strategy can significantly increase the number of cached important content without affecting the global hit rate and response delay, thereby improving the availability of important content.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127255599","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350758
Qian Xie, Duo Guo, Tong Wang, Xiaoping Yang, Xinghua Liu
In this paper, the finite-time synchronization and identification problem is investigated for Markovian switching delayed networks with multiple weighs, where the effects of nonlinear coupling and stochastic disturbances on the networks are considered. In the process of finite-time synchronization, the stability of the networks will be affected by a large number of controlled nodes, and then an effective control method is necessary to design and adopt. Under this control strategy, the finite-time synchronization of the networks is realized, and at the same time, the unknown parameter vector of the networks can also be identified in a finite time. Finally, a representative numerical simulation is provided to further prove the feasibility and applicability of the research content.
{"title":"Finite-Time Synchronization and Identification of Markovian Switching Delayed Networks with Multiple Weights","authors":"Qian Xie, Duo Guo, Tong Wang, Xiaoping Yang, Xinghua Liu","doi":"10.1109/HotICN50779.2020.9350758","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350758","url":null,"abstract":"In this paper, the finite-time synchronization and identification problem is investigated for Markovian switching delayed networks with multiple weighs, where the effects of nonlinear coupling and stochastic disturbances on the networks are considered. In the process of finite-time synchronization, the stability of the networks will be affected by a large number of controlled nodes, and then an effective control method is necessary to design and adopt. Under this control strategy, the finite-time synchronization of the networks is realized, and at the same time, the unknown parameter vector of the networks can also be identified in a finite time. Finally, a representative numerical simulation is provided to further prove the feasibility and applicability of the research content.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133071854","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350754
Christos Nasis, Christos-Alexandros Sarros, V. Tsaoussidis
Internet usage has evolved during the years towards accessing content, regardless of its location. The Named Data Networking architecture was designed to satisfy that need and replace today’s host-centric TCP/IP stack by placing named content at the core of the architecture. In this paper, we provide the first evaluation specifically targeting the impact of packet size in NDN performance. Our results show the impact of chunk sizes is far from negligible; it clearly affects NDN performance as measured by metrics such as throughput, delay, cache hits and cache entry lifetime. Attention should, therefore, be given to the selection of an appropriate chunk size in NDN deployments.
{"title":"The Impact of Chunk Size on Named Data Networking Performance","authors":"Christos Nasis, Christos-Alexandros Sarros, V. Tsaoussidis","doi":"10.1109/HotICN50779.2020.9350754","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350754","url":null,"abstract":"Internet usage has evolved during the years towards accessing content, regardless of its location. The Named Data Networking architecture was designed to satisfy that need and replace today’s host-centric TCP/IP stack by placing named content at the core of the architecture. In this paper, we provide the first evaluation specifically targeting the impact of packet size in NDN performance. Our results show the impact of chunk sizes is far from negligible; it clearly affects NDN performance as measured by metrics such as throughput, delay, cache hits and cache entry lifetime. Attention should, therefore, be given to the selection of an appropriate chunk size in NDN deployments.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115153514","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350854
Chengyuan Huang, Jiao Zhang, Tao Huang
The most important benefit introduced by multi-path TCP (MPTCP) is its ability of resource pooling. The congestion control algorithm and the packet scheduler in MPTCP work together to consume the pooled network resource of different sub-paths. However, the objectives of a MPTCP congestion control algorithm and a packet scheduler are not always in agreement with each other, which hinders the enhancement of the applications’ performance. In this paper, we propose Partner, a distributed Deep Reinforcement Learning (DRL)-based congestion control algorithm in MPTCP. By setting the reward function which is in agreement with the corresponding packet scheduler, Partner can accurately shape the decision space utilized by the packet scheduler, thus unleashing its full power. Our results show that Partner significantly outperforms the state-of-the-art congestion control algorithms in terms of meeting various applications’ requirements.
{"title":"Objective-Oriented Resource Pooling in MPTCP: A Deep Reinforcement Learning Approach","authors":"Chengyuan Huang, Jiao Zhang, Tao Huang","doi":"10.1109/HotICN50779.2020.9350854","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350854","url":null,"abstract":"The most important benefit introduced by multi-path TCP (MPTCP) is its ability of resource pooling. The congestion control algorithm and the packet scheduler in MPTCP work together to consume the pooled network resource of different sub-paths. However, the objectives of a MPTCP congestion control algorithm and a packet scheduler are not always in agreement with each other, which hinders the enhancement of the applications’ performance. In this paper, we propose Partner, a distributed Deep Reinforcement Learning (DRL)-based congestion control algorithm in MPTCP. By setting the reward function which is in agreement with the corresponding packet scheduler, Partner can accurately shape the decision space utilized by the packet scheduler, thus unleashing its full power. Our results show that Partner significantly outperforms the state-of-the-art congestion control algorithms in terms of meeting various applications’ requirements.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124808759","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 : 2020-12-12DOI: 10.1109/HotICN50779.2020.9350801
Lei Lei, C. Lan, L. Lin
A number of well-known BFT (Byzantine Fault Tolerant) algorithms, such as Tendermint, Casper, HotStuff, and Grandpa, have been developed in recent years to solve the problem of consensus. Of them, Tendermint can ensure instant finality but needs multiple rounds to commit a block. Casper and HotStuff both need a constraint on the direct parent to commit to a block. Grandpa uses ghost function to extract a common block from a vote set, but it is not based on a chained model and does not use signature aggregation to boost performance. We propose a consensus algorithm based on the theories of Tendermint and HotStuff. It is based on the same network model (each message sent out can reach every replica eventually, the adversary can hold it but not forever) and adversary assumption (the adversary can do Byzantine behavior like not proposing block or sending vote, or sending contradictory votes) as in Tendermint, but does not have the feature of instant finality. The result is an increase in throughput, since the blocks are handled in the chained model, the processes of handling each block can overlap.
{"title":"Chained Tendermint: A Parallel BFT Consensus Mechanism","authors":"Lei Lei, C. Lan, L. Lin","doi":"10.1109/HotICN50779.2020.9350801","DOIUrl":"https://doi.org/10.1109/HotICN50779.2020.9350801","url":null,"abstract":"A number of well-known BFT (Byzantine Fault Tolerant) algorithms, such as Tendermint, Casper, HotStuff, and Grandpa, have been developed in recent years to solve the problem of consensus. Of them, Tendermint can ensure instant finality but needs multiple rounds to commit a block. Casper and HotStuff both need a constraint on the direct parent to commit to a block. Grandpa uses ghost function to extract a common block from a vote set, but it is not based on a chained model and does not use signature aggregation to boost performance. We propose a consensus algorithm based on the theories of Tendermint and HotStuff. It is based on the same network model (each message sent out can reach every replica eventually, the adversary can hold it but not forever) and adversary assumption (the adversary can do Byzantine behavior like not proposing block or sending vote, or sending contradictory votes) as in Tendermint, but does not have the feature of instant finality. The result is an increase in throughput, since the blocks are handled in the chained model, the processes of handling each block can overlap.","PeriodicalId":125282,"journal":{"name":"2020 3rd International Conference on Hot Information-Centric Networking (HotICN)","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124768877","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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