We present a scalable protocol for database joins on secret shared data in the honest-majority three-party setting. The key features of our protocol are a rich set of SQL-like join/select queries and the ability to compose join operations together due to the inputs and outputs being generically secret shared between the parties. Provided that all joins operate on unique primary keys, no information is revealed to any party during the protocol. In particular, not even the sizes of intermediate joins are revealed. All of our protocols are constant-round and achieve O(n) communication and computation overhead for joining two tables of n rows. These properties make our protocol ideal for outsourced secure computation. In this setting several non-colluding servers are setup and the input data is shared among them. These servers then perform the relevant secret shared computation and output the result. This model has recently been gaining traction in industry, e.g. Facebook's Crypten, Cape Privacy's TFEncrypted, Mozilla Telemetry. We additionally implement two applications on top of our framework. The first application detects voter registration errors within and between agencies of 50 US states, in a privacy-preserving manner. The second application allows several organizations to compare network security logs to more accurately identify common security threats, e.g. the IP addresses of a bot net. In both cases, the practicality of these applications depends on efficiently performing joins on millions of secret shared records. For example, our three party protocol can perform a join on two sets of 1 million records in 4.9 seconds or, alternatively, compute the cardinality of this join in just 3.1 seconds.
我们提出了一种可扩展的协议，用于在诚实多数三方环境下对秘密共享数据进行数据库连接。我们协议的关键特性是一组丰富的类似sql的连接/选择查询，以及将连接操作组合在一起的能力，因为输入和输出在各方之间通常是秘密共享的。如果所有连接都在唯一主键上操作，则在协议期间不会向任何一方透露任何信息。特别是，中间连接的大小都没有显示出来。我们所有的协议都是恒轮的，并且在连接两个n行表时实现0 (n)的通信和计算开销。这些属性使我们的协议成为外包安全计算的理想选择。在此设置中，设置多个非串通服务器，并在它们之间共享输入数据。然后，这些服务器执行相关的秘密共享计算并输出结果。这种模式最近在行业中越来越受欢迎，例如Facebook的Crypten, Cape Privacy的TFEncrypted, Mozilla Telemetry。我们还在框架之上实现了两个应用程序。第一个应用程序以保护隐私的方式检测美国50个州的机构内部和机构之间的选民登记错误。第二个应用程序允许多个组织比较网络安全日志，以更准确地识别常见的安全威胁，例如僵尸网络的IP地址。在这两种情况下，这些应用程序的实用性取决于对数百万个秘密共享记录有效地执行连接。例如，我们的三方协议可以在4.9秒内对两组100万条记录执行连接，或者在3.1秒内计算此连接的基数。
{"title":"Fast Database Joins and PSI for Secret Shared Data","authors":"Payman Mohassel, Peter Rindal, Mike Rosulek","doi":"10.1145/3372297.3423358","DOIUrl":"https://doi.org/10.1145/3372297.3423358","url":null,"abstract":"We present a scalable protocol for database joins on secret shared data in the honest-majority three-party setting. The key features of our protocol are a rich set of SQL-like join/select queries and the ability to compose join operations together due to the inputs and outputs being generically secret shared between the parties. Provided that all joins operate on unique primary keys, no information is revealed to any party during the protocol. In particular, not even the sizes of intermediate joins are revealed. All of our protocols are constant-round and achieve O(n) communication and computation overhead for joining two tables of n rows. These properties make our protocol ideal for outsourced secure computation. In this setting several non-colluding servers are setup and the input data is shared among them. These servers then perform the relevant secret shared computation and output the result. This model has recently been gaining traction in industry, e.g. Facebook's Crypten, Cape Privacy's TFEncrypted, Mozilla Telemetry. We additionally implement two applications on top of our framework. The first application detects voter registration errors within and between agencies of 50 US states, in a privacy-preserving manner. The second application allows several organizations to compare network security logs to more accurately identify common security threats, e.g. the IP addresses of a bot net. In both cases, the practicality of these applications depends on efficiently performing joins on millions of secret shared records. For example, our three party protocol can perform a join on two sets of 1 million records in 4.9 seconds or, alternatively, compute the cardinality of this join in just 3.1 seconds.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85370834","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}
Kang Yang, Chenkai Weng, Xiao Lan, Jiang Zhang, Xiao Wang
Correlated oblivious transfer (COT) is a crucial building block for secure multi-party computation (MPC) and can be generated efficiently via OT extension. Recent works based on the pseudorandom correlation generator (PCG) paradigm presented a new way to generate random COT correlations using only communication sublinear to the output length. However, due to their high computational complexity, these protocols are only faster than the classical IKNP-style OT extension under restricted network bandwidth. In this paper, we propose new COT protocols in the PCG paradigm that achieve unprecedented performance. em With $50$ Mbps network bandwidth, our maliciously secure protocol can produce one COT correlation in $22$ nanoseconds. More specifically, our results are summarized as follows: beginenumerate item We propose a semi-honest COT protocol with sublinear communication and linear computation. This protocol assumes primal-LPN and is built upon a recent VOLE protocol with semi-honest security by Schoppmann et al. (CCS 2019). We are able to apply various optimizations to reduce its communication cost by roughly $15times$, not counting a one-time setup cost that diminishes as we generate more COT correlations. item We strengthen our COT protocol to malicious security with no loss of efficiency. Among all optimizations, our new protocol features a new checking technique that ensures correctness and consistency essentially for free. In particular, our maliciously secure protocol is only em $1-3$ nanoseconds slower for each COT. item We implemented our protocols, and the code will be publicly available at EMP toolkit. We observe at least $9times$ improvement in running time compared to the state-of-the-art protocol by Boyle et al. (CCS 2019) in both semi-honest and malicious settings under any network faster than $50$ Mbps. endenumerate With this new record of efficiency for generating COT correlations, we anticipate new protocol designs and optimizations will flourish on top of our protocol.
{"title":"Ferret: Fast Extension for Correlated OT with Small Communication","authors":"Kang Yang, Chenkai Weng, Xiao Lan, Jiang Zhang, Xiao Wang","doi":"10.1145/3372297.3417276","DOIUrl":"https://doi.org/10.1145/3372297.3417276","url":null,"abstract":"Correlated oblivious transfer (COT) is a crucial building block for secure multi-party computation (MPC) and can be generated efficiently via OT extension. Recent works based on the pseudorandom correlation generator (PCG) paradigm presented a new way to generate random COT correlations using only communication sublinear to the output length. However, due to their high computational complexity, these protocols are only faster than the classical IKNP-style OT extension under restricted network bandwidth. In this paper, we propose new COT protocols in the PCG paradigm that achieve unprecedented performance. em With $50$ Mbps network bandwidth, our maliciously secure protocol can produce one COT correlation in $22$ nanoseconds. More specifically, our results are summarized as follows: beginenumerate item We propose a semi-honest COT protocol with sublinear communication and linear computation. This protocol assumes primal-LPN and is built upon a recent VOLE protocol with semi-honest security by Schoppmann et al. (CCS 2019). We are able to apply various optimizations to reduce its communication cost by roughly $15times$, not counting a one-time setup cost that diminishes as we generate more COT correlations. item We strengthen our COT protocol to malicious security with no loss of efficiency. Among all optimizations, our new protocol features a new checking technique that ensures correctness and consistency essentially for free. In particular, our maliciously secure protocol is only em $1-3$ nanoseconds slower for each COT. item We implemented our protocols, and the code will be publicly available at EMP toolkit. We observe at least $9times$ improvement in running time compared to the state-of-the-art protocol by Boyle et al. (CCS 2019) in both semi-honest and malicious settings under any network faster than $50$ Mbps. endenumerate With this new record of efficiency for generating COT correlations, we anticipate new protocol designs and optimizations will flourish on top of our protocol.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"213 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79478172","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}
Long Cheng, Christin Wilson, Song Liao, Jeffrey Young, Daniel Dong, Hongxin Hu
With the emergence of the voice personal assistant (VPA) ecosystem, third-party developers are allowed to build new voice-apps are called skills in the Amazon Alexa platform and actions in the Google Assistant platform, respectively. For the sake of brevity, we use the term skills to describe voice-apps including Amazon skills and Google actions, unless we need to distinguish them for different VPA platforms. and publish them to the skills store, which greatly extends the functionalities of VPAs. Before a new skill becomes publicly available, that skill must pass a certification process, which verifies that it meets the necessary content and privacy policies. The trustworthiness of skill certification is of significant importance to platform providers, developers, and end users. Yet, little is known about how difficult it is for a policy-violating skill to get certified and published in VPA platforms. In this work, we study the trustworthiness of the skill certification in Amazon Alexa and Google Assistant platforms to answer three key questions: 1) Whether the skill certification process is trustworthy in terms of catching policy violations in third-party skills. 2) Whether there exist policy-violating skills published in their skills stores. 3) What are VPA users' perspectives on the skill certification and their vulnerable usage behavior when interacting with VPA devices? Over a span of 15 months, we crafted and submitted for certification 234 Amazon Alexa skills and 381 Google Assistant actions that intentionally violate content and privacy policies specified by VPA platforms. Surprisingly, we successfully got 234 (100%) policy-violating Alexa skills certified and 148 (39%) policy-violating Google actions certified. Our analysis demonstrates that policy-violating skills exist in the current skills stores, and thus users (children, in particular) are at risk when using VPA services. We conducted a user study with 203 participants to understand users' misplaced trust on VPA platforms. Unfortunately, user expectations are not being met by the skill certification in leading VPA platforms.
{"title":"Dangerous Skills Got Certified: Measuring the Trustworthiness of Skill Certification in Voice Personal Assistant Platforms","authors":"Long Cheng, Christin Wilson, Song Liao, Jeffrey Young, Daniel Dong, Hongxin Hu","doi":"10.1145/3372297.3423339","DOIUrl":"https://doi.org/10.1145/3372297.3423339","url":null,"abstract":"With the emergence of the voice personal assistant (VPA) ecosystem, third-party developers are allowed to build new voice-apps are called skills in the Amazon Alexa platform and actions in the Google Assistant platform, respectively. For the sake of brevity, we use the term skills to describe voice-apps including Amazon skills and Google actions, unless we need to distinguish them for different VPA platforms. and publish them to the skills store, which greatly extends the functionalities of VPAs. Before a new skill becomes publicly available, that skill must pass a certification process, which verifies that it meets the necessary content and privacy policies. The trustworthiness of skill certification is of significant importance to platform providers, developers, and end users. Yet, little is known about how difficult it is for a policy-violating skill to get certified and published in VPA platforms. In this work, we study the trustworthiness of the skill certification in Amazon Alexa and Google Assistant platforms to answer three key questions: 1) Whether the skill certification process is trustworthy in terms of catching policy violations in third-party skills. 2) Whether there exist policy-violating skills published in their skills stores. 3) What are VPA users' perspectives on the skill certification and their vulnerable usage behavior when interacting with VPA devices? Over a span of 15 months, we crafted and submitted for certification 234 Amazon Alexa skills and 381 Google Assistant actions that intentionally violate content and privacy policies specified by VPA platforms. Surprisingly, we successfully got 234 (100%) policy-violating Alexa skills certified and 148 (39%) policy-violating Google actions certified. Our analysis demonstrates that policy-violating skills exist in the current skills stores, and thus users (children, in particular) are at risk when using VPA services. We conducted a user study with 203 participants to understand users' misplaced trust on VPA platforms. Unfortunately, user expectations are not being met by the skill certification in leading VPA platforms.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80198587","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}
We present KEMTLS, an alternative to the TLS 1.3 handshake that uses key-encapsulation mechanisms (KEMs) instead of signatures for server authentication. Among existing post-quantum candidates, signature schemes generally have larger public key/signature sizes compared to the public key/ciphertext sizes of KEMs: by using an IND-CCA-secure KEM for server authentication in post-quantum TLS, we obtain multiple benefits. A size-optimized post-quantum instantiation of KEMTLS requires less than half the bandwidth of a size-optimized post-quantum instantiation of TLS 1.3. In a speed-optimized instantiation, KEMTLS reduces the amount of server CPU cycles by almost 90% compared to TLS 1.3, while at the same time reducing communication size, reducing the time until the client can start sending encrypted application data, and eliminating code for signatures from the server's trusted code base.
{"title":"Post-Quantum TLS Without Handshake Signatures","authors":"P. Schwabe, D. Stebila, Thom Wiggers","doi":"10.1145/3372297.3423350","DOIUrl":"https://doi.org/10.1145/3372297.3423350","url":null,"abstract":"We present KEMTLS, an alternative to the TLS 1.3 handshake that uses key-encapsulation mechanisms (KEMs) instead of signatures for server authentication. Among existing post-quantum candidates, signature schemes generally have larger public key/signature sizes compared to the public key/ciphertext sizes of KEMs: by using an IND-CCA-secure KEM for server authentication in post-quantum TLS, we obtain multiple benefits. A size-optimized post-quantum instantiation of KEMTLS requires less than half the bandwidth of a size-optimized post-quantum instantiation of TLS 1.3. In a speed-optimized instantiation, KEMTLS reduces the amount of server CPU cycles by almost 90% compared to TLS 1.3, while at the same time reducing communication size, reducing the time until the client can start sending encrypted application data, and eliminating code for signatures from the server's trusted code base.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86281656","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}
App-in-app is a new and trending mobile computing paradigm in which native app-like software modules, called sub-apps, are hosted by popular mobile apps such as Wechat, Baidu, TikTok and Chrome, to enrich the host app's functionalities and to form an "all-in-one app" ecosystem. Sub-apps access system resources through the host, and their functionalities come close to regular mobile apps (taking photos, recording voices, banking, shopping, etc.). Less clear, however, is whether the host app, typically a third-party app, is capable of securely managing sub-apps and their access to system resources. In this paper, we report the first systematic study on the resource management in app-in-app systems. Our study reveals high-impact security flaws, which allow the adversary to stealthily escalate privilege (e.g., accessing the camera, photo gallery, microphone, etc.) or acquire sensitive data (e.g., location, passwords of Amazon, Google, etc.). To understand the impacts of those flaws, we developed an analysis tool that automatically assesses 11 popular app-in-app platforms on both Android and iOS. Our results brought to light the prevalence of the security flaws. We further discuss the lessons learned and propose mitigation strategies.
{"title":"Demystifying Resource Management Risks in Emerging Mobile App-in-App Ecosystems","authors":"Haoran Lu, Luyi Xing, Yue Xiao, Yifan Zhang, Xiaojing Liao, Xiaofeng Wang, Xueqiang Wang","doi":"10.1145/3372297.3417255","DOIUrl":"https://doi.org/10.1145/3372297.3417255","url":null,"abstract":"App-in-app is a new and trending mobile computing paradigm in which native app-like software modules, called sub-apps, are hosted by popular mobile apps such as Wechat, Baidu, TikTok and Chrome, to enrich the host app's functionalities and to form an \"all-in-one app\" ecosystem. Sub-apps access system resources through the host, and their functionalities come close to regular mobile apps (taking photos, recording voices, banking, shopping, etc.). Less clear, however, is whether the host app, typically a third-party app, is capable of securely managing sub-apps and their access to system resources. In this paper, we report the first systematic study on the resource management in app-in-app systems. Our study reveals high-impact security flaws, which allow the adversary to stealthily escalate privilege (e.g., accessing the camera, photo gallery, microphone, etc.) or acquire sensitive data (e.g., location, passwords of Amazon, Google, etc.). To understand the impacts of those flaws, we developed an analysis tool that automatically assesses 11 popular app-in-app platforms on both Android and iOS. Our results brought to light the prevalence of the security flaws. We further discuss the lessons learned and propose mitigation strategies.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86373664","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}
K. Wüst, Sinisa Matetic, Silvan Egli, Kari Kostiainen, Srdjan Capkun
Smart contracts are programmable, decentralized and transparent financial applications. Because smart contract platforms typically support Turing-complete programming languages, such systems are often said to enable arbitrary applications. However, the current permissionless smart contract systems impose heavy restrictions on the types of computations that can be implemented. For example, the globally-replicated and sequential execution model of Ethereum requires low gas limits that make many computations infeasible. In this paper, we propose a novel system called ACE whose main goal is to enable more complex smart contracts on permissionless blockchains. ACE is based on an off-chain execution model where the contract issuers appoint a set of service providers to execute the contract code independent from the consensus layer. The primary advantage of ACE over previous solutions is that it allows one contract to safely call another contract that is executed by a different set of service providers. Thus, ACE is the first solution to enable off-chain execution of interactive smart contracts with flexible trust assumptions. Our evaluation shows that ACE enables several orders of magnitude more complex smart contracts than standard Ethereum.
{"title":"ACE: Asynchronous and Concurrent Execution of Complex Smart Contracts","authors":"K. Wüst, Sinisa Matetic, Silvan Egli, Kari Kostiainen, Srdjan Capkun","doi":"10.1145/3372297.3417243","DOIUrl":"https://doi.org/10.1145/3372297.3417243","url":null,"abstract":"Smart contracts are programmable, decentralized and transparent financial applications. Because smart contract platforms typically support Turing-complete programming languages, such systems are often said to enable arbitrary applications. However, the current permissionless smart contract systems impose heavy restrictions on the types of computations that can be implemented. For example, the globally-replicated and sequential execution model of Ethereum requires low gas limits that make many computations infeasible. In this paper, we propose a novel system called ACE whose main goal is to enable more complex smart contracts on permissionless blockchains. ACE is based on an off-chain execution model where the contract issuers appoint a set of service providers to execute the contract code independent from the consensus layer. The primary advantage of ACE over previous solutions is that it allows one contract to safely call another contract that is executed by a different set of service providers. Thus, ACE is the first solution to enable off-chain execution of interactive smart contracts with flexible trust assumptions. Our evaluation shows that ACE enables several orders of magnitude more complex smart contracts than standard Ethereum.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88022753","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}
Francesca Falzon, Evangelia Anna Markatou, Akshima, David Cash, A. Rivkin, J. Stern, R. Tamassia
In the past few years, we have seen multiple attacks on one-dimensional databases that support range queries. These attacks achieve full database reconstruction by exploiting access pattern leakage along with known query distribution or search pattern leakage. We are the first to go beyond one dimension, exploring this threat in two dimensions. We unveil an intrinsic limitation of reconstruction attacks by showing that there can be an exponential number of distinct databases that produce equivalent leakage. Next, we present a full database reconstruction attack. Our algorithm runs in polynomial time and returns a poly-size encoding of all databases consistent with the given leakage profile. We implement our algorithm and observe real-world databases that admit a large number of equivalent databases, which aligns with our theoretical results.
{"title":"Full Database Reconstruction in Two Dimensions","authors":"Francesca Falzon, Evangelia Anna Markatou, Akshima, David Cash, A. Rivkin, J. Stern, R. Tamassia","doi":"10.1145/3372297.3417275","DOIUrl":"https://doi.org/10.1145/3372297.3417275","url":null,"abstract":"In the past few years, we have seen multiple attacks on one-dimensional databases that support range queries. These attacks achieve full database reconstruction by exploiting access pattern leakage along with known query distribution or search pattern leakage. We are the first to go beyond one dimension, exploring this threat in two dimensions. We unveil an intrinsic limitation of reconstruction attacks by showing that there can be an exponential number of distinct databases that produce equivalent leakage. Next, we present a full database reconstruction attack. Our algorithm runs in polynomial time and returns a poly-size encoding of all databases consistent with the given leakage profile. We implement our algorithm and observe real-world databases that admit a large number of equivalent databases, which aligns with our theoretical results.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85398696","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}
Synchronous consensus protocols, by definition, have a worst-case commit latency that depends on the bounded network delay. The notion of optimistic responsiveness was recently introduced to allow synchronous protocols to commit instantaneously when some optimistic conditions are met. In this work, we revisit this notion of optimistic responsiveness and present optimal latency results. We present a lower bound for Byzantine Broadcast that relates the latency of optimistic and synchronous commits when the designated sender is honest and while the optimistic commit can tolerate some faults. We then present two matching upper bounds for tolerating f faults out of $n = 2f+1$ parties. Our first upper bound result achieves optimal optimistic and synchronous commit latency when the designated sender is honest and the optimistic commit can tolerate at least one fault. We experimentally evaluate this protocol and show that it achieves throughput comparable to state-of-the-art synchronous and partially synchronous protocols and under optimistic conditions achieves latency better than the state-of-the-art. Our second upper bound result achieves optimal optimistic and synchronous commit latency when the designated sender is honest but the optimistic commit does not tolerate any faults. The presence of matching lower and upper bound results make both of the results tight for $n = 2f+1$. Our upper bound results are presented in a state machine replication setting with a steady-state leader who is replaced with a view-change protocol when they do not make progress. For this setting, we also present an optimistically responsive protocol where the view-change protocol is optimistically responsive too.
{"title":"On the Optimality of Optimistic Responsiveness","authors":"Ittai Abraham, Kartik Nayak, Ling Ren, Nibesh Shrestha","doi":"10.1145/3372297.3417284","DOIUrl":"https://doi.org/10.1145/3372297.3417284","url":null,"abstract":"Synchronous consensus protocols, by definition, have a worst-case commit latency that depends on the bounded network delay. The notion of optimistic responsiveness was recently introduced to allow synchronous protocols to commit instantaneously when some optimistic conditions are met. In this work, we revisit this notion of optimistic responsiveness and present optimal latency results. We present a lower bound for Byzantine Broadcast that relates the latency of optimistic and synchronous commits when the designated sender is honest and while the optimistic commit can tolerate some faults. We then present two matching upper bounds for tolerating f faults out of $n = 2f+1$ parties. Our first upper bound result achieves optimal optimistic and synchronous commit latency when the designated sender is honest and the optimistic commit can tolerate at least one fault. We experimentally evaluate this protocol and show that it achieves throughput comparable to state-of-the-art synchronous and partially synchronous protocols and under optimistic conditions achieves latency better than the state-of-the-art. Our second upper bound result achieves optimal optimistic and synchronous commit latency when the designated sender is honest but the optimistic commit does not tolerate any faults. The presence of matching lower and upper bound results make both of the results tight for $n = 2f+1$. Our upper bound results are presented in a state machine replication setting with a steady-state leader who is replaced with a view-change protocol when they do not make progress. For this setting, we also present an optimistically responsive protocol where the view-change protocol is optimistically responsive too.","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"102 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91218868","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}
{"title":"Session details: Session 2A: ML and Information Leakage","authors":"Murat Kantarcioglu","doi":"10.1145/3432962","DOIUrl":"https://doi.org/10.1145/3432962","url":null,"abstract":"","PeriodicalId":20481,"journal":{"name":"Proceedings of the 2020 ACM SIGSAC Conference on Computer and Communications Security","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91340054","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}
Chip-Hong Chang, S. Katzenbeisser, U. Rührmair, P. Schaumont
The workshop on "Attacks and Solutions in HardwarE Security"(ASHES) welcomes any theoretical and practical works on hardware security, including attacks, solutions, countermeasures, proofs, classification, formalization, and implementations. Besides mainstream research, ASHES puts some focus on new and emerging scenarios: This includes the internet of things (IoT), nuclear weapons inspections, arms control, consumer and infrastructure security, or supply chain security, among others. ASHES also welcomes dedicated works on special purpose hardware, such as lightweight, low-cost, and energy-efficient devices, or non-electronic security systems. The workshop hosts four different paper categories: Apart from regular and short papers, this includes works that systematize and structure a certain (sub-)area (so-called "Systematization of Knowledge" (SoK) papers), and so-termed "Wild and Crazy" (WaC) papers, which distribute seminal ideas at an early conceptual stage. This summary gives a brief overview of the fourth edition of the workshop, which will take place virtually on November 13, 2020, as a post-conference satellite workshop of ACM CCS.
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