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Analysis of LFT2 [article]

Geunwoo Lim, Yujin Kwon, Yongdae Kim
<span title="2020-04-08">2020</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
For a decentralized and transparent society, blockchain technology has been developed. Along with this, quite a few consensus algorithms that are one of core technologies in blockchain have been proposed. Among them, we analyze a consensus algorithm called LFT2, which is used by a blockchain system, ICON. We first formulate the LFT2 consensus algorithm and then analyze safety and liveness, which can be considered as the most important properties in distributed consensus system. We prove that
more &raquo; ... 2 satisfies safety and liveness, where a certain assumption is required to prove liveness. In addition, we compare LFT2 with two similar consensus algorithms, and from the comparison, we show that a trade-off exist among the three consensus algorithms. Finally, we simulate LFT2 to measure a liveness quality.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/2004.04294v1">arXiv:2004.04294v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/jztar6uzxjbsnfvisrtmiu7o64">fatcat:jztar6uzxjbsnfvisrtmiu7o64</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200411004356/https://arxiv.org/pdf/2004.04294v1.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/2004.04294v1" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

Is Stellar As Secure As You Think? [article]

Minjeong Kim, Yujin Kwon, Yongdae Kim
<span title="2019-04-29">2019</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
Stellar is one of the top ten cryptocurrencies in terms of market capitalization. It adopts a variant of Byzantine fault tolerance (BFT), named federated Byzantine agreement (FBA), which generalizes the traditional BFT algorithm to make it more suitable for open-membership blockchains. To this end, FBA introduces a quorum slice concept, which consists of a set of nodes. In FBA, a node can complete one consensus round when it receives specific messages from nodes in a quorum slice appointed by
more &raquo; ... e node. In this study, we analyze FBA, whose security is highly dependent on the structure of quorum slices, and demonstrate that it is not superior to the traditional BFT algorithm in terms of safety and liveness. Then, to analyze the security of the Stellar consensus protocol (SCP), which is a construction for FBA, we investigate the current quorum slices in Stellar. We analyze the structure of quorum slices and measure the influence of each node quantitatively using two metrics, PageRank (PR) and the newly proposed NodeRank (NR). The results show that the Stellar system is significantly centralized. Thereafter, to determine how the centralized structure can have a negative impact on the Stellar system, we study the cascading failure caused by deleting only a few nodes (i.e., validators) in Stellar. We show that all of the nodes in Stellar cannot run SCP if only two nodes fail. To make matters worse, these two nodes are run and controlled by a single organization, the Stellar foundation.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1904.13302v1">arXiv:1904.13302v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/jreemdckojdyrhwtdjpzkw4ouq">fatcat:jreemdckojdyrhwtdjpzkw4ouq</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20191017102600/https://arxiv.org/pdf/1904.13302v1.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/41/37/41375b1c0de654437c0b8dd7cdcca1aa76225dbe.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1904.13302v1" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

BurnFit: Analyzing and Exploiting Wearable Devices [chapter]

Dongkwan Kim, Suwan Park, Kibum Choi, Yongdae Kim
<span title="">2016</span> <i title="Springer International Publishing"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/2w3awgokqne6te4nvlofavy5a4" style="color: black;">Lecture Notes in Computer Science</a> </i> &nbsp;
Wearable devices have recently become popular, and more and more people now buy and wear these devices to obtain health-related services. However, as wearable device technology quickly advances, its security cannot keep up with the speed of its development. As a result, it is highly likely for the devices to have severe vulnerabilities. Moreover, because these wearable devices are usually light-weight, they delegate a large portion of their operations as well as permissions to a software
more &raquo; ... s on computers or smartphones, which put users at high risk if there are vulnerabilities in these gateways. In order to validate this claim, we analyzed three devices as a case study and found a total 17 vulnerabilities in them. We verified that an adversary can utilize these vulnerabilities to compromise the software gateway and take over a victim's computers and smartphones. We also suggest possible mitigation to improve the security of wearable devices.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-319-31875-2_19">doi:10.1007/978-3-319-31875-2_19</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/drt44ue7tjeu3gij2tyn4k5xq4">fatcat:drt44ue7tjeu3gij2tyn4k5xq4</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20190220183233/http://pdfs.semanticscholar.org/27db/c44d671c7dc1ba0bb04fd7b954b458c05033.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/27/db/27dbc44d671c7dc1ba0bb04fd7b954b458c05033.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-319-31875-2_19"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> springer.com </button> </a>

Impossibility of Full Decentralization in Permissionless Blockchains [article]

Yujin Kwon, Jian Liu, Minjeong Kim, Dawn Song, Yongdae Kim
<span title="2019-09-01">2019</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
In addition, Kim et al. analyzed the Stellar system and concluded that the system is significantly centralized [83] . Solutions.  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1905.05158v2">arXiv:1905.05158v2</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/7pm7rm4g4ffrpexctuaziofvke">fatcat:7pm7rm4g4ffrpexctuaziofvke</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200913062331/https://arxiv.org/pdf/1905.05158v2.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/f4/46/f446405a14a3f24d754d4d7bed3f16c0eab4fbcd.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1905.05158v2" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

Be Selfish and Avoid Dilemmas: Fork After Withholding (FAW) Attacks on Bitcoin [article]

Yujin Kwon, Dohyun Kim, Yunmok Son, Eugene Vasserman, Yongdae Kim
<span title="2017-08-31">2017</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
In the Bitcoin system, participants are rewarded for solving cryptographic puzzles. In order to receive more consistent rewards over time, some participants organize mining pools and split the rewards from the pool in proportion to each participant's contribution. However, several attacks threaten the ability to participate in pools. The block withholding (BWH) attack makes the pool reward system unfair by letting malicious participants receive unearned wages while only pretending to contribute
more &raquo; ... work. When two pools launch BWH attacks against each other, they encounter the miner's dilemma: in a Nash equilibrium, the revenue of both pools is diminished. In another attack called selfish mining, an attacker can unfairly earn extra rewards by deliberately generating forks. In this paper, we propose a novel attack called a fork after withholding (FAW) attack. FAW is not just another attack. The reward for an FAW attacker is always equal to or greater than that for a BWH attacker, and it is usable up to four times more often per pool than in BWH attack. When considering multiple pools - the current state of the Bitcoin network - the extra reward for an FAW attack is about 56% more than that for a BWH attack. Furthermore, when two pools execute FAW attacks on each other, the miner's dilemma may not hold: under certain circumstances, the larger pool can consistently win. More importantly, an FAW attack, while using intentional forks, does not suffer from practicality issues, unlike selfish mining. We also discuss partial countermeasures against the FAW attack, but finding a cheap and efficient countermeasure remains an open problem. As a result, we expect to see FAW attacks among mining pools.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1708.09790v1">arXiv:1708.09790v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/4qgtwfyysjaazopzirw4a2pyhi">fatcat:4qgtwfyysjaazopzirw4a2pyhi</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200826002313/https://arxiv.org/pdf/1708.09790v1.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/62/f3/62f309095540687b58babef434834f2969bb7cf9.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1708.09790v1" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

Breaking and Fixing VoLTE

Hongil Kim, Dongkwan Kim, Minhee Kwon, Hyungseok Han, Yeongjin Jang, Dongsu Han, Taesoo Kim, Yongdae Kim
<span title="">2015</span> <i title="ACM Press"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/rau5643b7ncwvh74y6p64hntle" style="color: black;">Proceedings of the 22nd ACM SIGSAC Conference on Computer and Communications Security - CCS &#39;15</a> </i> &nbsp;
Long Term Evolution (LTE) is becoming the dominant cellular networking technology, shifting the cellular network away from its circuit-switched legacy towards a packet-switched network that resembles the Internet. To support voice calls over the LTE network, operators have introduced Voice-over-LTE (VoLTE), which dramatically changes how voice calls are handled, both from user equipment and infrastructure perspectives. We find that this dramatic shift opens up a number of new attack surfaces
more &raquo; ... t have not been previously explored. To call attention to this matter, this paper presents a systematic security analysis. Unlike the traditional call setup, the VoLTE call setup is controlled and performed at the Application Processor (AP), using the SIP over IP. A legitimate user who has control over the AP can potentially control and exploit the call setup process to establish a VoLTE channel. This combined with the legacy accounting policy (e.g., unlimited voice and the separation of data and voice) leads to a number of free data channels. In the process of unveiling the free data channels, we identify a number of additional vulnerabilities of early VoLTE implementations, which lead to serious exploits, such as caller spoofing, over-billing, and denial-of-service attacks. We identify the nature of these vulnerabilities and concrete exploits that directly result from the adoption of VoLTE. We also propose immediate countermeasures that can be employed to alleviate the problems. However, we believe that the nature of the problem calls for a more comprehensive solution that eliminates the root causes at mobile devices, mobile platforms, and the core network.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1145/2810103.2813718">doi:10.1145/2810103.2813718</a> <a target="_blank" rel="external noopener" href="https://dblp.org/rec/conf/ccs/KimKKHJHKK15.html">dblp:conf/ccs/KimKKHJHKK15</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/ysol25urefddzphvu5dt4kx62q">fatcat:ysol25urefddzphvu5dt4kx62q</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170201052926/http://ina.kaist.ac.kr/~dongsuh/paper/kim-ccs15.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/53/73/5373ecf60adadd0d59c20836003d9d967e3b524f.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1145/2810103.2813718"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> acm.org </button> </a>

Privacy Preserving Nearest Neighbor Search [chapter]

Mark Shaneck, Yongdae Kim, Vipin Kumar
<span title="">2009</span> <i title="Springer US"> Machine Learning in Cyber Trust </i> &nbsp;
Data mining is frequently obstructed by privacy concerns. In many cases data is distributed, and bringing the data together in one place for analysis is not possible due to privacy laws (e.g. HIPAA) or policies. Privacy preserving data mining techniques have been developed to address this issue by providing mechanisms to mine the data while giving certain privacy guarantees. In this work we address the issue of privacy preserving nearest neighbor search, which forms the kernel of many data
more &raquo; ... g applications. To this end, we present a novel algorithm based on secure multiparty computation primitives to compute the nearest neighbors of records in horizontally distributed data. We show how this algorithm can be used in three important data mining algorithms, namely LOF outlier detection, SNN clustering, and kNN classification.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-0-387-88735-7_10">doi:10.1007/978-0-387-88735-7_10</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/obtqow5n2rcftgnfquik5jtnji">fatcat:obtqow5n2rcftgnfquik5jtnji</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20160413085249/http://syssec.kaist.ac.kr/~yongdaek/doc/padm2006.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/69/2a/692a0a845c004524813638e939e3dbee3fe6acd8.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-0-387-88735-7_10"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> springer.com </button> </a>

SocialCloud: Using Social Networks for Building Distributed Computing Services [article]

Abedelaziz Mohaisen and Huy Tran and Abhishek Chandra and Yongdae Kim
<span title="2011-12-10">2011</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
In this paper we investigate a new computing paradigm, called SocialCloud, in which computing nodes are governed by social ties driven from a bootstrapping trust-possessing social graph. We investigate how this paradigm differs from existing computing paradigms, such as grid computing and the conventional cloud computing paradigms. We show that incentives to adopt this paradigm are intuitive and natural, and security and trust guarantees provided by it are solid. We propose metrics for
more &raquo; ... the utility and advantage of this computing paradigm, and using real-world social graphs and structures of social traces; we investigate the potential of this paradigm for ordinary users. We study several design options and trade-offs, such as scheduling algorithms, centralization, and straggler handling, and show how they affect the utility of the paradigm. Interestingly, we conclude that whereas graphs known in the literature for high trust properties do not serve distributed trusted computing algorithms, such as Sybil defenses---for their weak algorithmic properties, such graphs are good candidates for our paradigm for their self-load-balancing features.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1112.2254v1">arXiv:1112.2254v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/clbpkvsx5neopmhzr4pb3yibha">fatcat:clbpkvsx5neopmhzr4pb3yibha</a> </span>
<a target="_blank" rel="noopener" href="https://archive.org/download/arxiv-1112.2254/1112.2254.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> File Archive [PDF] </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1112.2254v1" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

An Efficient Tree-Based Group Key Agreement Using Bilinear Map [chapter]

Sangwon Lee, Yongdae Kim, Kwangjo Kim, Dae-Hyun Ryu
<span title="">2003</span> <i title="Springer Berlin Heidelberg"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/2w3awgokqne6te4nvlofavy5a4" style="color: black;">Lecture Notes in Computer Science</a> </i> &nbsp;
Kim et al.[9] proposed a secure, simple and efficient key management method, called TGDH(Tree-based Group Diffie-Hellman) protocol, which uses key tree with Diffie-Hellman key exchange to efficiently compute  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-540-45203-4_28">doi:10.1007/978-3-540-45203-4_28</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/l76qlxe6hzcatanm2pndkkpjka">fatcat:l76qlxe6hzcatanm2pndkkpjka</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170922053050/http://koasas.kaist.ac.kr/bitstream/10203/15954/1/26.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/31/47/3147328e23afbe4e6e2b596ccef4d0a6c9bba5d3.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-540-45203-4_28"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> springer.com </button> </a>

Bitcoin vs. Bitcoin Cash: Coexistence or Downfall of Bitcoin Cash? [article]

Yujin Kwon, Hyoungshick Kim, Jinwoo Shin, Yongdae Kim
<span title="2019-03-02">2019</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
In Aug. 2017, Bitcoin was split into the original Bitcoin (BTC) and Bitcoin Cash (BCH). Since then, miners have had a choice between BTC and BCH mining because they have compatible proof-of-work algorithms. Therefore, they can freely choose which coin to mine for higher profit, where the profitability depends on both the coin price and mining difficulty. Some miners can immediately switch the coin to mine only when mining difficulty changes because the difficulty changes are more predictable
more &raquo; ... n that for the coin price, and we call this behavior fickle mining. In this paper, we study the effects of fickle mining by modeling a game between two coins. To do this, we consider both fickle miners and some factions (e.g., BITMAIN for BCH mining) that stick to mining one coin to maintain that chain. In this model, we show that fickle mining leads to a Nash equilibrium in which only a faction sticking to its coin mining remains as a loyal miner to the less valued coin (e.g., BCH), where loyal miners refer to those who conduct mining even after coin mining difficulty increases. This situation would cause severe centralization, weakening the security of the coin system. To determine which equilibrium the competing coin systems (e.g., BTC vs. BCH) are moving toward, we traced the historical changes of mining power for BTC and BCH. In addition, we analyze the recent "hash war" between Bitcoin ABC and SV, which confirms our theoretical analysis. Finally, we note that our results can be applied to any competing cryptocurrency systems in which the same hardware (e.g., ASICs or GPUs) can be used for mining. Therefore, our study brings new and important angles in competitive coin markets: a coin can intentionally weaken the security and decentralization level of the other rival coin when mining hardware is shared between them, allowing for automatic mining.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1902.11064v2">arXiv:1902.11064v2</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/fwf754mhprbvboogy5kjcbnbqe">fatcat:fwf754mhprbvboogy5kjcbnbqe</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200903063917/https://arxiv.org/pdf/1902.11064v2.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/7f/38/7f38d3b6cd427ca9af0f30cfe87ae2bc3dfe8fb9.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1902.11064v2" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

Design and performance evaluation of thin-film actuators based on flexible Ni-Co substrates

Suhwan Kim, Woojin Kim, Yongdae Kim
<span title="2020-11-13">2020</span> <i title="Springer Science and Business Media LLC"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/vrcckbwrrzha7cqcoig65t6k5i" style="color: black;">Micro and Nano Systems Letters</a> </i> &nbsp;
AbstractThis paper proposes a new design of bimorph-type electrothermal actuators based on flexible Ni-Co substrates and describes the results of the finite element method (FEM) simulation and performance evaluation of the actuators. In the design of the actuators, a multilayer structure consisting of an adhesion layer, two insulation layers, and a Pt (platinum) heater layer was formed on the Ni-Co flexible substrate that was patterned in an individual shape. The thin-film actuators proposed in
more &raquo; ... this study could be detached from a Si carrier wafer and adhered to other micro or macrostructural elements. To investigate the temperature distribution and mechanical behavior of the actuators, multiphysics FEM simulations combining electrothermal and static structural analyses were carried out. The actuators were fabricated using conventional microfabrication and electroplating technologies on Si carrier wafer; then, the actuators were peeled off from the carrier wafer using the release process proposed in this paper. After fabricating the actuators, the deflection of their tips was evaluated and compared with that obtained from the FEM simulations.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1186/s40486-020-00122-z">doi:10.1186/s40486-020-00122-z</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/4rybwmu2svb3bevjwjtjmzvojy">fatcat:4rybwmu2svb3bevjwjtjmzvojy</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20201114141902/https://mnsl-journal.springeropen.com/track/pdf/10.1186/s40486-020-00122-z.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/a7/f0/a7f01493dc277e34e71e787e8b1999a3d11561c7.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1186/s40486-020-00122-z"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="unlock alternate icon" style="background-color: #fb971f;"></i> springer.com </button> </a>

Batch Verifications with ID-Based Signatures [chapter]

HyoJin Yoon, Jung Hee Cheon, Yongdae Kim
<span title="">2005</span> <i title="Springer Berlin Heidelberg"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/2w3awgokqne6te4nvlofavy5a4" style="color: black;">Lecture Notes in Computer Science</a> </i> &nbsp;
An identity (ID)-based signature scheme allows any pair of users to verify each other's signatures without exchanging public key certificates. With the advent of Bilinear maps, several ID-based signatures based on the discrete logarithm problem have been proposed. While these signatures have an advantage in the fact that the system secret can be shared by several parties using a threshold scheme (thereby overcoming the security problem of RSA-based ID-based signature schemes), they all share
more &raquo; ... same efficiency disadvantage. To overcome this, some schemes have focused on finding ways to verify multiple signatures at the same time (i.e. the batch verification problem). While they had some success in improving efficiency of verification, each had a slightly diversified definition of batch verification. In this paper, we propose a taxonomy of batch verification against which we analyze security of well-known ID-based signature schemes. We also propose a new ID-based signature scheme that allows for all types of multiple signature batch verification, and prove its security in random oracle model.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/11496618_18">doi:10.1007/11496618_18</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/vwpgbvbntzfsxkm7lsxdtjn3ae">fatcat:vwpgbvbntzfsxkm7lsxdtjn3ae</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20070417222837/http://www.math.snu.ac.kr/~jhcheon/Published/2004_ICISC_Aggr/ICISC2004_YCK.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/81/01/8101aaa4508a9409e44fdf9865e924d325155a8f.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/11496618_18"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> springer.com </button> </a>

Stochastic optical active rheology

Hyungsuk Lee, Yongdae Shin, Sun Taek Kim, Ellis L. Reinherz, Matthew J. Lang
<span title="2012-07-16">2012</span> <i title="AIP Publishing"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/gahdfbfwljgajfxqbum465rt4u" style="color: black;">Applied Physics Letters</a> </i> &nbsp;
We demonstrate a stochastic based method for performing active rheology using optical tweezers. By monitoring the displacement of an embedded particle in response to stochastic optical forces, a rapid estimate of the frequency dependent shear moduli of a sample is achieved in the range of 10 À1 -10 3 Hz. We utilize the method to probe linear viscoelastic properties of hydrogels at varied cross-linker concentrations. Combined with fluorescence imaging, our method demonstrates non-linear changes
more &raquo; ... f bond strength between T cell receptors and an antigenic peptide due to force-induced cell activation. V C 2012 American Institute of Physics. [http://dx.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1063/1.4737159">doi:10.1063/1.4737159</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/22893729">pmid:22893729</a> <a target="_blank" rel="external noopener" href="https://pubmed.ncbi.nlm.nih.gov/PMC3411558/">pmcid:PMC3411558</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/bkxnz6ejq5fybfm7e2ubcuvlvy">fatcat:bkxnz6ejq5fybfm7e2ubcuvlvy</a> </span>
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Dynamix

Abedelaziz Mohaisen, Yongdae Kim
<span title="">2013</span> <i title="ACM Press"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/rau5643b7ncwvh74y6p64hntle" style="color: black;">Proceedings of the 8th ACM SIGSAC symposium on Information, computer and communications security - ASIA CCS &#39;13</a> </i> &nbsp;
In this paper we advance communication using social networks in two directions by considering dynamics of social graphs. First, we formally define the problem of routing on dynamic graphs and show an interesting and intuitive connection between graph dynamics and random walks on weighted graphs; graphs in which weights summarize history of edge dynamics and allow for future dynamics to be used as weight adjustment. Second, we present several measurements of our proposed model on dynamic graphs
more &raquo; ... xtracted from real-world social networks and compare them to static structures driven from the same graphs. We show several interesting trade-offs and highlight the potential of our model to capture dynamics, enrich graph structure, and improves the quantitative sender anonymity when compared to the case of static graphs.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1145/2484313.2484334">doi:10.1145/2484313.2484334</a> <a target="_blank" rel="external noopener" href="https://dblp.org/rec/conf/ccs/MohaisenK13.html">dblp:conf/ccs/MohaisenK13</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/r7o42dsmvzcn3bvzj34mibipxm">fatcat:r7o42dsmvzcn3bvzj34mibipxm</a> </span>
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Pay as You Want: Bypassing Charging System in Operational Cellular Networks [chapter]

Hyunwook Hong, Hongil Kim, Byeongdo Hong, Dongkwan Kim, Hyunwoo Choi, Eunkyu Lee, Yongdae Kim
<span title="">2017</span> <i title="Springer International Publishing"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/2w3awgokqne6te4nvlofavy5a4" style="color: black;">Lecture Notes in Computer Science</a> </i> &nbsp;
Kim et al. [9] demonstrated that four free data channels were available: direct communication of phone-to-phone and phone-to-Internet and SIP/media tunneling.  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-319-56549-1_13">doi:10.1007/978-3-319-56549-1_13</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/al53sdrovbhployrapcfejolz4">fatcat:al53sdrovbhployrapcfejolz4</a> </span>
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