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Bank run Payment Channel Networks [article]

Zhichun Lu, Runchao Han, Jiangshan Yu
2020 IACR Cryptology ePrint Archive  
Parameter ā is the number of attempts before the attack. 0.001 0.007 0.013 0.019 µ 15.0% 31.8% 31.2% 39.2% ā 1.76 2.59 2.66 3.11 © Zhichun Lu, Runchao Han and Jiangshan Yu; licensed under Creative  ...  Commons License CC-BY 4.0 OpenAccess Series in Informatics Schloss Dagstuhl -Leibniz-Zentrum für Informatik, Dagstuhl Publishing, Germany © Zhichun Lu, Runchao Han and Jiangshan Yu; licensed under  ... 
dblp:journals/iacr/LuHY20 fatcat:qfb6akqmrvh4fd2qlmnu6ntama

Analysing and Improving Shard Allocation Protocols for Sharded Blockchains [article]

Runchao Han, Jiangshan Yu, Ren Zhang
2020 IACR Cryptology ePrint Archive  
Sharding is a promising approach to scale permissionless blockchains. In a sharded blockchain, participants are split into groups, called shards, and each shard only executes part of the workloads. Despite its wide adoption in permissioned systems, transferring such success to permissionless blockchains is still an open problem. In permissionless networks, participants may join and leave the system at any time, making load balancing challenging. In addition, the adversary in such networks can
more » ... unch the single-shard takeover attack by compromising a single shard's consensus. To address these issues, participants should be securely and dynamically allocated into different shards. However, the protocol capturing such functionality -which we call shard allocation -is overlooked. In this paper, we study shard allocation protocols for permissionless blockchains. We formally define the shard allocation protocol and propose an evaluation framework. We apply the framework to evaluate the shard allocation subprotocols of seven state-of-the-art sharded blockchains, and show that none of them is fully correct or achieves satisfactory performance. We attribute these deficiencies to their redundant security assumptions that limit their performance, and their extreme choices between two performance metrics: self-balance and operability. We observe and prove the fundamental trade-off between these two metrics, and identify a new property memory-dependency that enables parametrisation over this trade-off. Based on these insights, we propose WORMHOLE, a correct and efficient shard allocation protocol with minimal security assumptions and parametrisable self-balance and operability. We implement WORMHOLE and evaluate its overhead and performance metrics in a network with 128 shards and 32768 nodes. The results show that WORMHOLE introduces little overhead, achieves consistent self-balance and operability with our theoretical analysis, and allows the system to recover quickly from load imbalance.
dblp:journals/iacr/HanYZ20 fatcat:i6mkmmvzorff7kycwa4pe7uday

RandChain: Decentralised Randomness Beacon from Sequential Proof-of-Work [article]

Runchao Han, Jiangshan Yu, Haoyu Lin
2020 IACR Cryptology ePrint Archive  
We propose RANDCHAIN, a Decentralised Randomness Beacon (DRB) that is the first to achieve both scalability (i.e., a large number of participants can join) and fairness (i.e., each participant controls comparable power on deciding random outputs). Unlike existing DRBs where participants are collaborative, i.e., aggregating their local entropy into a single output, participants in RANDCHAIN are competitive, i.e., competing with each other to generate the next output. The competitive design
more » ... s the communication complexity from at least O(n 2 ) to O(n) without trusted party, breaking the scalability limit in existing DRBs. To build RANDCHAIN, we introduce Sequential Proof-of-Work (SeqPoW), a cryptographic puzzle that takes a random and unpredictable number of sequential steps to solve. We implement RANDCHAIN and evaluate its performance on up to 1024 nodes, demonstrating its superiority (1.3 seconds per output with a constant bandwidth of 200KB/s per node) compared to stateof-the-art DRBs RandHerd (S&P'18) and HydRand (S&P'20).
dblp:journals/iacr/HanYL20 fatcat:i2m7q7prwzgzlctztldwndriqe

On the Security and Performance of Blockchain Sharding [article]

Runchao Han, Jiangshan Yu, Haoyu Lin, Shiping Chen, Paulo Jorge Esteves Veríssimo
2021 IACR Cryptology ePrint Archive  
In this paper, we perform a comprehensive evaluation on blockchain sharding protocols. We deconstruct the blockchain sharding protocol into four foundational layers with orthogonal functionalities, securing some properties. We evaluate each layer of seven state-of-the-art blockchain sharding protocols, and identify a considerable number of new attacks, questionable design trade-offs and some open challenges. The layered evaluation allows us to unveil security and performance problems arising
more » ... m a fundamental design choice, namely the coherence of system settings across layers. In particular, most sharded blockchains use different trust and synchrony assumptions across layers, without corresponding architectural guarantees. Unless a hybrid architecture were used, assuming differentiated system settings across layers can introduce subtle but severe failure syndromes or reduce the system's performance.
dblp:journals/iacr/HanYLCV21 fatcat:i3iqlut63fdofe5xd7r4dnkqri

Effects of transarterial chemoembolization on the immunological function of patients with hepatocellular carcinoma

Jingjing Guo, Saixia Wang, Yujing Han, Zhongyuan Jia, Runchao Wang
2021 Oncology Letters  
The present study aimed to investigate the effects of transarterial chemoembolization (TACE) on the immune function of patients with hepatocellular carcinoma (HCC). A total of 114 patients with HCC were selected and their peripheral blood was collected before and 1 month after TACE treatment. Flow cytometry and reverse transcription-quantitative PCR were performed to analyze the changes in immune function in patients before and after treatment. Kaplan-Meier curves were plotted for survival
more » ... sis. The programmed cell death ligand 1 (PD-L1) and programmed cell death protein 1 (PD1) expression before TACE treatment were significantly higher in patients with poor TACE response compared with those patients with well response. Higher PD-L1 mRNA expression in the peripheral blood mononuclear cells after TACE predicted a superior prognosis. After TACE treatment, the proportion of CD4+/CD8+ cells were decreased while the expression levels of programmed cell death protein 1 (PD1) were significantly increased. To conclude, TACE could reduce the proportion of CD4+/CD8+ cells and improve the mRNA expression levels of PD1 in patients with HCC. The expression levels of PD1 and PD-L1 were closely related to the therapeutic effect of TACE and the prognosis of patients with HCC. TACE combined with immunotherapy may have potential clinical value for patients with HCC.
doi:10.3892/ol.2021.12815 pmid:34084221 pmcid:PMC8161415 fatcat:uayo7sh36rdw3evs43sornn2fu

Demystifying Crypto-Mining: Analysis and Optimizations of Memory-Hard PoW Algorithms

Runchao Han, Nikos Foutris, Christos Kotselidis
2019 2019 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS)  
Blockchain technology has become extremely popular, during the last decade, mainly due to the successful application in the cryptocurrency domain. Following the explosion of Bitcoin and other cryptocurrencies, blockchain solutions are being deployed in almost every aspect of transactional operations as a means to safely exchange digital assets between non-trusted parties. At the heart of every blockchain deployment is the consensus protocol, which maintains the consistency of the blockchain
more » ... satisfying incoming transactions. Although many consensus protocols have been recently introduced, the most prevalent is Proof-of-Work, which scales the blockchain globally by converting the consensus problem to a competition based on cryptographic hash functions; a process called "mining". The Proof-of-Work consensus protocol employs memoryhard algorithms in order to counteract ASIC or FPGA mining that may compromise the decentralization and democratization of the blockchain. Unfortunately, this leads to increased power consumption and scalability challenges since numerous processing units such as GPUs, FPGAs, and ASICs, are required to satisfy the ever-increasing operational requirements of blockchain deployments. In this paper, we perform an in-depth performance analysis and characterization of the most common memory-hard PoW algorithms running on NVIDIA GPUs. Motivated by our experimental findings, we apply a series of optimizations on Ethash algorithm, the consensus protocol of the Ethereum blockchain. The implemented optimizations accelerate performance by 14% and improve energy efficiency by 10% when executing on three NVIDIA GPUs. As a result, the optimized Ethash algorithm outperformed its fastest commercial implementation.
doi:10.1109/ispass.2019.00011 dblp:conf/ispass/HanFK19 fatcat:vydexmzt7jfcrpclkesw2mjnim

General Congestion Attack on HTLC-Based Payment Channel Networks

Zhichun Lu, Runchao Han, Jiangshan Yu, Vincent Gramoli, Hanna Halaburda, Rafael Pass
2022
Han, and J.  ...  Han, and J. Yu 2:9 Algorithm 2 Launching attack.  ... 
doi:10.4230/oasics.tokenomics.2021.2 fatcat:tag3dda5izd7hgvrt3ma3xvf2q

Author Index

2021 2021 13th International Conference on Intelligent Human-Machine Systems and Cybernetics (IHMSC)  
150 Feng, Chen 133 Feng, Shiling 216 Feng, Weiqiang 87 Fu, Hao 227 Gao, Jing 146 Gao, Shangce 39 Ge, Dehui 20 Ge, Genyu 172 Ge, Rui 1 Gui, Qing 216 Guo, Luqing 108 Han  ...  16 Jiang, Qin 172 Jin, Chuchu 103 Jin, Xuan 95 Junkai, Liu 196 Li, Chaoshun 133 Li, Chen 190 Li, Fang 49 Li, Huafeng 29 Li, Jiayi 39 Li, Lin 29 Li, Rui 75, 162 Li, Runchao  ... 
doi:10.1109/ihmsc52134.2021.00060 fatcat:ixooov6axnc45h2bsjaasnepge

Blockchain, Fog and IoT Integrated Framework: Review, Architecture and Evaluation [article]

Tanweer Alam, Mohamed Benaida
2020 arXiv   pre-print
In 2018, Runchao Han et.al. were published an article based on the evaluation of blocks in blockchains network of the internet of things.  ... 
arXiv:2006.03596v1 fatcat:6n54pzajf5h45alodqsegzgyqe

The StakeCube blockchain : Instantiation, Evaluation & Applications

Antoine Durand, Guillaume Hebert, Khalifa Toumi, Gerard Memmi, Emmanuelle Anceaume
2020 2020 Second International Conference on Blockchain Computing and Applications (BCCA)  
Runchao Han et al. evaluated several blockchains specifically with IoT in mind [9] , namely Hyperledger Fabric v0.6 with PBFT, Fabric v1.0 with BFT-SMaRt, Ripple with BFT Ripple consensus, Tendermint  ... 
doi:10.1109/bcca50787.2020.9274084 fatcat:fu3d4ysgsve5rgbk3vyqm7h7ay

Scaling Distributed Ledgers and Privacy-Preserving Applications [article]

Alberto Sonnino
2021 arXiv   pre-print
In International Conference on Very Large Data Bases, 1993. [156] Runchao Han, Gary Shapiro, Vincent Gramoli, and Xiwei Xu.  ...  In sharded systems, some transactions may operate on objects han- dled by different shards, effectively requiring the relevant shards to additionally run a cross-shard consensus protocol to enable agreement  ... 
arXiv:2102.12273v1 fatcat:3twoaysg7rcj7h4yogwsyyzd34