Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security最新文献
Cloud computing is quickly becoming the platform of choice for many web services. Virtualization is the key underlying technology enabling cloud providers to host services for a large number of customers. Unfortunately, virtualization software is large, complex, and has a considerable attack surface. As such, it is prone to bugs and vulnerabilities that a malicious virtual machine (VM) can exploit to attack or obstruct other VMs -- a major concern for organizations wishing to move to the cloud. In contrast to previous work on hardening or minimizing the virtualization software, we eliminate the hypervisor attack surface by enabling the guest VMs to run natively on the underlying hardware while maintaining the ability to run multiple VMs concurrently. Our NoHype system embodies four key ideas: (i) pre-allocation of processor cores and memory resources, (ii) use of virtualized I/O devices, (iii) minor modifications to the guest OS to perform all system discovery during bootup, and (iv) avoiding indirection by bringing the guest virtual machine in more direct contact with the underlying hardware. Hence, no hypervisor is needed to allocate resources dynamically, emulate I/O devices, support system discovery after bootup, or map interrupts and other identifiers. NoHype capitalizes on the unique use model in cloud computing, where customers specify resource requirements ahead of time and providers offer a suite of guest OS kernels. Our system supports multiple tenants and capabilities commonly found in hosted cloud infrastructures. Our prototype utilizes Xen 4.0 to prepare the environment for guest VMs, and a slightly modified version of Linux 2.6 for the guest OS. Our evaluation with both SPEC and Apache benchmarks shows a roughly 1% performance gain when running applications on NoHype compared to running them on top of Xen 4.0. Our security analysis shows that, while there are some minor limitations with cur- rent commodity hardware, NoHype is a significant advance in the security of cloud computing.
{"title":"Eliminating the hypervisor attack surface for a more secure cloud","authors":"Jakub Szefer, Eric Keller, R. Lee, J. Rexford","doi":"10.1145/2046707.2046754","DOIUrl":"https://doi.org/10.1145/2046707.2046754","url":null,"abstract":"Cloud computing is quickly becoming the platform of choice for many web services. Virtualization is the key underlying technology enabling cloud providers to host services for a large number of customers. Unfortunately, virtualization software is large, complex, and has a considerable attack surface. As such, it is prone to bugs and vulnerabilities that a malicious virtual machine (VM) can exploit to attack or obstruct other VMs -- a major concern for organizations wishing to move to the cloud. In contrast to previous work on hardening or minimizing the virtualization software, we eliminate the hypervisor attack surface by enabling the guest VMs to run natively on the underlying hardware while maintaining the ability to run multiple VMs concurrently. Our NoHype system embodies four key ideas: (i) pre-allocation of processor cores and memory resources, (ii) use of virtualized I/O devices, (iii) minor modifications to the guest OS to perform all system discovery during bootup, and (iv) avoiding indirection by bringing the guest virtual machine in more direct contact with the underlying hardware. Hence, no hypervisor is needed to allocate resources dynamically, emulate I/O devices, support system discovery after bootup, or map interrupts and other identifiers. NoHype capitalizes on the unique use model in cloud computing, where customers specify resource requirements ahead of time and providers offer a suite of guest OS kernels. Our system supports multiple tenants and capabilities commonly found in hosted cloud infrastructures. Our prototype utilizes Xen 4.0 to prepare the environment for guest VMs, and a slightly modified version of Linux 2.6 for the guest OS. Our evaluation with both SPEC and Apache benchmarks shows a roughly 1% performance gain when running applications on NoHype compared to running them on top of Xen 4.0. Our security analysis shows that, while there are some minor limitations with cur- rent commodity hardware, NoHype is a significant advance in the security of cloud computing.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"34 1","pages":"401-412"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90032501","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}
C. Brzuska, M. Fischlin, B. Warinschi, S. C. Williams
In this paper we examine composability properties for the fundamental task of key exchange. Roughly speaking, we show that key exchange protocols secure in the prevalent model of Bellare and Rogaway can be composed with arbitrary protocols that require symmetrically distributed keys. This composition theorem holds if the key exchange protocol satisfies an additional technical requirement that our analysis brings to light: it should be possible to determine which sessions derive equal keys given only the publicly available information. What distinguishes our results from virtually all existing work is that we do not rely, neither directly nor indirectly, on the simulation paradigm. Instead, our security notions and composition theorems exclusively use a game-based formalism.We thus avoid several undesirable consequences of simulation-based security notions and support applicability to a broader class of protocols. In particular, we offer an abstract formalization of game-based security that should be of independent interest in other investigations using game-based formalisms.
{"title":"Composability of bellare-rogaway key exchange protocols","authors":"C. Brzuska, M. Fischlin, B. Warinschi, S. C. Williams","doi":"10.1145/2046707.2046716","DOIUrl":"https://doi.org/10.1145/2046707.2046716","url":null,"abstract":"In this paper we examine composability properties for the fundamental task of key exchange. Roughly speaking, we show that key exchange protocols secure in the prevalent model of Bellare and Rogaway can be composed with arbitrary protocols that require symmetrically distributed keys. This composition theorem holds if the key exchange protocol satisfies an additional technical requirement that our analysis brings to light: it should be possible to determine which sessions derive equal keys given only the publicly available information. What distinguishes our results from virtually all existing work is that we do not rely, neither directly nor indirectly, on the simulation paradigm. Instead, our security notions and composition theorems exclusively use a game-based formalism.We thus avoid several undesirable consequences of simulation-based security notions and support applicability to a broader class of protocols. In particular, we offer an abstract formalization of game-based security that should be of independent interest in other investigations using game-based formalisms.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"23 1","pages":"51-62"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82964237","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}
Browser designers create security mechanisms to help web developers protect web applications, but web developers are usually slow to use these features in web-based applications (web apps). In this paper we introduce Zan, a browser-based system for applying new browser security mechanisms to legacy web apps automatically. Our key insight is that web apps often contain enough information, via web developer source-code patterns or key properties of web-app objects, to allow the browser to infer opportunities for applying new security mechanisms to existing web apps. We apply this new concept to protect authentication cookies, prevent web apps from being framed unwittingly, and perform JavaScript object deserialization safely. We evaluate Zan on up to the 1000 most popular websites for each of the three cases. We find that Zan can provide complimentary protection for the majority of potentially applicable websites automatically without requiring additional code from the web developers and with negligible incompatibility impact.
{"title":"Fortifying web-based applications automatically","authors":"Shuo Tang, Nathan Dautenhahn, Samuel T. King","doi":"10.1145/2046707.2046777","DOIUrl":"https://doi.org/10.1145/2046707.2046777","url":null,"abstract":"Browser designers create security mechanisms to help web developers protect web applications, but web developers are usually slow to use these features in web-based applications (web apps). In this paper we introduce Zan, a browser-based system for applying new browser security mechanisms to legacy web apps automatically. Our key insight is that web apps often contain enough information, via web developer source-code patterns or key properties of web-app objects, to allow the browser to infer opportunities for applying new security mechanisms to existing web apps. We apply this new concept to protect authentication cookies, prevent web apps from being framed unwittingly, and perform JavaScript object deserialization safely. We evaluate Zan on up to the 1000 most popular websites for each of the three cases. We find that Zan can provide complimentary protection for the majority of potentially applicable websites automatically without requiring additional code from the web developers and with negligible incompatibility impact.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"15 1","pages":"615-626"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82814785","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}
S. Maggi, Alberto Volpatto, Simone Gasparini, G. Boracchi, S. Zanero
Touchscreen devices increase the risk of shoulder surfing to such an extent that attackers could steal sensitive information by simply following the victim and observe his or her portable device. We underline this concern by proposing an automatic shoulder surfing attack against modern touchscreen keyboards that display magnified keys in predictable positions. We demonstrate this attack against the Apple iPhone - although it can work with other layouts and different devices - and show that it recognizes up to 97.07% (91.03% on average) of the keystrokes, with only 1.15% of errors, at 37 to 51 keystrokes per minute: About eight times faster than a human analyzing a recorded video. Our attack, described thoroughly in [2], accurately recovers the sequence of keystrokes input by the user. The attack described in [1], which targeted desktop scenarios and thus worked with very restrictive settings, is similar in spirit to ours. However, as it assumes that camera and target keyboard are both in fixed, perpendicular position, it cannot suite mobile settings, characterized by moving target and skewed, rotated viewpoints. Our attack, instead, requires no particular settings and even allows for natural movements of both target device and shoulder surfer's camera. In addition, our attack yields accurate output without any grammar or syntax checks, so that it can detect large context-free text or non-dictionary words. In summary: - We are the first studying the practical risks brought forth by mainstream touchscreen keyboards. - We design a practical attack that detects keystrokes on modern touchscreen keyboards: The attacker requires not to stand exactly behind the victim nor to observe the screen perpendicularly. Our attack is robust to occlusions (eg, typing fingers), thanks to our efficient filtering technique that validates detected keys and reconstructs keystroke sequences accurately.
{"title":"Poster: fast, automatic iPhone shoulder surfing","authors":"S. Maggi, Alberto Volpatto, Simone Gasparini, G. Boracchi, S. Zanero","doi":"10.1145/2046707.2093498","DOIUrl":"https://doi.org/10.1145/2046707.2093498","url":null,"abstract":"Touchscreen devices increase the risk of shoulder surfing to such an extent that attackers could steal sensitive information by simply following the victim and observe his or her portable device. We underline this concern by proposing an automatic shoulder surfing attack against modern touchscreen keyboards that display magnified keys in predictable positions. We demonstrate this attack against the Apple iPhone - although it can work with other layouts and different devices - and show that it recognizes up to 97.07% (91.03% on average) of the keystrokes, with only 1.15% of errors, at 37 to 51 keystrokes per minute: About eight times faster than a human analyzing a recorded video. Our attack, described thoroughly in [2], accurately recovers the sequence of keystrokes input by the user. The attack described in [1], which targeted desktop scenarios and thus worked with very restrictive settings, is similar in spirit to ours. However, as it assumes that camera and target keyboard are both in fixed, perpendicular position, it cannot suite mobile settings, characterized by moving target and skewed, rotated viewpoints. Our attack, instead, requires no particular settings and even allows for natural movements of both target device and shoulder surfer's camera. In addition, our attack yields accurate output without any grammar or syntax checks, so that it can detect large context-free text or non-dictionary words.\u0000 In summary: - We are the first studying the practical risks brought forth by mainstream touchscreen keyboards. - We design a practical attack that detects keystrokes on modern touchscreen keyboards: The attacker requires not to stand exactly behind the victim nor to observe the screen perpendicularly. Our attack is robust to occlusions (eg, typing fingers), thanks to our efficient filtering technique that validates detected keys and reconstructs keystroke sequences accurately.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"12 1","pages":"805-808"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85877090","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}
The sheer volume of new malware found each day is growing at an exponential pace. This growth has created a need for automatic malware triage techniques that determine what malware is similar, what malware is unique, and why. In this paper, we present BitShred, a system for large-scale malware similarity analysis and clustering, and for automatically uncovering semantic inter- and intra-family relationships within clusters. The key idea behind BitShred is using feature hashing to dramatically reduce the high-dimensional feature spaces that are common in malware analysis. Feature hashing also allows us to mine correlated features between malware families and samples using co-clustering techniques. Our evaluation shows that BitShred speeds up typical malware triage tasks by up to 2,365x and uses up to 82x less memory on a single CPU, all with comparable accuracy to previous approaches. We also develop a parallelized version of BitShred, and demonstrate scalability within the Hadoop framework.
{"title":"BitShred: feature hashing malware for scalable triage and semantic analysis","authors":"Jiyong Jang, David Brumley, Shobha Venkataraman","doi":"10.1145/2046707.2046742","DOIUrl":"https://doi.org/10.1145/2046707.2046742","url":null,"abstract":"The sheer volume of new malware found each day is growing at an exponential pace. This growth has created a need for automatic malware triage techniques that determine what malware is similar, what malware is unique, and why. In this paper, we present BitShred, a system for large-scale malware similarity analysis and clustering, and for automatically uncovering semantic inter- and intra-family relationships within clusters. The key idea behind BitShred is using feature hashing to dramatically reduce the high-dimensional feature spaces that are common in malware analysis. Feature hashing also allows us to mine correlated features between malware families and samples using co-clustering techniques. Our evaluation shows that BitShred speeds up typical malware triage tasks by up to 2,365x and uses up to 82x less memory on a single CPU, all with comparable accuracy to previous approaches. We also develop a parallelized version of BitShred, and demonstrate scalability within the Hadoop framework.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"40 1","pages":"309-320"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75707426","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}
Erik-Oliver Blass, Kaoutar Elkhiyaoui, R. Molva, O. Savry, Cédric Vérhilac
In this demo, we present the realization and evaluation of a wireless hardware prototype of the previously proposed RFID authentication protocol 'Ff'. The motivation has been to get as close as possible to the (expensive) construction of a wafer and to analyze and demonstrate Ff's real-world feasibility and functional correctness in the field. Besides showing Ff's feasibility, our objective is to show implications of embedding authentication into an industry RFID communication standard. Apart from the documentation at hand, the demonstrator comprises the Ff RFID tag and reader prototypes and a standard EPC tag and reader. The hardware is connected to a laptop controlling the hardware and simulating attacks against authentication.
{"title":"Demo: the ff hardware prototype for privacy-preserving RFID authentication","authors":"Erik-Oliver Blass, Kaoutar Elkhiyaoui, R. Molva, O. Savry, Cédric Vérhilac","doi":"10.1145/2046707.2093481","DOIUrl":"https://doi.org/10.1145/2046707.2093481","url":null,"abstract":"In this demo, we present the realization and evaluation of a wireless hardware prototype of the previously proposed RFID authentication protocol 'Ff'. The motivation has been to get as close as possible to the (expensive) construction of a wafer and to analyze and demonstrate Ff's real-world feasibility and functional correctness in the field. Besides showing Ff's feasibility, our objective is to show implications of embedding authentication into an industry RFID communication standard. Apart from the documentation at hand, the demonstrator comprises the Ff RFID tag and reader prototypes and a standard EPC tag and reader. The hardware is connected to a laptop controlling the hardware and simulating attacks against authentication.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"39 1","pages":"737-740"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74750447","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}
The prevalence of spam URLs in Internet services, such as email, social networks, blogs and online forums has become a serious problem. These spam URLs host spam advertisements, phishing attempts, and malwares, which are harmful for normal users. Existing URL blacklist approaches offer limited protection. Although recentmachine learning based URL classification approaches demonstrate good accuracy and reasonable throughput, they are based on observations fromexisting spamURLs and hard to detect new spam URLs when attackers employ new strategies. In this paper, we present CUD (Crowdsourcing for URL spam detection) as a supplement of existing detection tools. CUD leverages human intelligence for URL classification through crowdsourcing. CUD crawls existing user comments about spamURLs already on the Internet, and employs sentiment analysis from nature language processing to analyze the user comments automatically for detecting spam URLs. Since CUD does not using features directly associated with the URLs and their landing pages, it is more robust when attackers change their strategies. Through evaluation, we find up to 70% of URLs have user comments online. CUD achieves an accuracy of 86.8% in terms of true positive rate with a false positive rate 0.9%. Moreover, about 75% of spam URLs CUD detects are missed by other approaches. Therefore, CUD can be used as a good complement to other approaches.
在诸如电子邮件、社交网络、博客和在线论坛等互联网服务中，垃圾url的流行已经成为一个严重的问题。这些垃圾url包含垃圾广告、网络钓鱼企图和恶意软件，对普通用户是有害的。现有的URL黑名单方法提供有限的保护。尽管最近基于机器学习的URL分类方法显示出良好的准确性和合理的吞吐量，但它们是基于对现有垃圾URL的观察，当攻击者采用新的策略时，很难检测到新的垃圾URL。在本文中，我们提出了CUD (Crowdsourcing for URL spam detection)作为现有检测工具的补充。通过众包，CUD利用人类的智慧进行URL分类。CUD抓取互联网上已有的用户对垃圾url的评论，并采用自然语言处理中的情感分析对用户评论进行自动分析，从而检测出垃圾url。由于CUD不使用与url及其着陆页直接关联的特性，因此当攻击者改变策略时，它更加健壮。通过评估，我们发现高达70%的url有用户在线评论。CUD的真阳性率准确率为86.8%，假阳性率为0.9%。此外，CUD检测到的大约75%的垃圾url被其他方法遗漏了。因此，CUD可以作为其他方法的一个很好的补充。
{"title":"Poster: CUD: crowdsourcing for URL spam detection","authors":"Jun Hu, Hongyu Gao, Zhichun Li, Yan Chen","doi":"10.1145/2046707.2093493","DOIUrl":"https://doi.org/10.1145/2046707.2093493","url":null,"abstract":"The prevalence of spam URLs in Internet services, such as email, social networks, blogs and online forums has become a serious problem. These spam URLs host spam advertisements, phishing attempts, and malwares, which are harmful for normal users. Existing URL blacklist approaches offer limited protection. Although recentmachine learning based URL classification approaches demonstrate good accuracy and reasonable throughput, they are based on observations fromexisting spamURLs and hard to detect new spam URLs when attackers employ new strategies. In this paper, we present CUD (Crowdsourcing for URL spam detection) as a supplement of existing detection tools. CUD leverages human intelligence for URL classification through crowdsourcing. CUD crawls existing user comments about spamURLs already on the Internet, and employs sentiment analysis from nature language processing to analyze the user comments automatically for detecting spam URLs. Since CUD does not using features directly associated with the URLs and their landing pages, it is more robust when attackers change their strategies. Through evaluation, we find up to 70% of URLs have user comments online. CUD achieves an accuracy of 86.8% in terms of true positive rate with a false positive rate 0.9%. Moreover, about 75% of spam URLs CUD detects are missed by other approaches. Therefore, CUD can be used as a good complement to other approaches.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"86 1","pages":"785-788"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73856110","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}
XML Encryption was standardized by W3C in 2002, and is implemented in XML frameworks of major commercial and open-source organizations like Apache, redhat, IBM, and Microsoft. It is employed in a large number of major web-based applications, ranging from business communications, e-commerce, and financial services over healthcare applications to governmental and military infrastructures. In this work we describe a practical attack on XML Encryption, which allows to decrypt a ciphertext by sending related ciphertexts to a Web Service and evaluating the server response. We show that an adversary can decrypt a ciphertext by performing only 14 requests per plaintext byte on average. This poses a serious and truly practical security threat on all currently used implementations of XML Encryption. In a sense the attack can be seen as a generalization of padding oracle attacks (Vaudenay, Eurocrypt 2002). It exploits a subtle correlation between the block cipher mode of operation, the character encoding of encrypted text, and the response behaviour of a Web Service if an XML message cannot be parsed correctly.
{"title":"How to break XML encryption","authors":"Tibor Jager, Juraj Somorovsky","doi":"10.1145/2046707.2046756","DOIUrl":"https://doi.org/10.1145/2046707.2046756","url":null,"abstract":"XML Encryption was standardized by W3C in 2002, and is implemented in XML frameworks of major commercial and open-source organizations like Apache, redhat, IBM, and Microsoft. It is employed in a large number of major web-based applications, ranging from business communications, e-commerce, and financial services over healthcare applications to governmental and military infrastructures. In this work we describe a practical attack on XML Encryption, which allows to decrypt a ciphertext by sending related ciphertexts to a Web Service and evaluating the server response. We show that an adversary can decrypt a ciphertext by performing only 14 requests per plaintext byte on average. This poses a serious and truly practical security threat on all currently used implementations of XML Encryption.\u0000 In a sense the attack can be seen as a generalization of padding oracle attacks (Vaudenay, Eurocrypt 2002). It exploits a subtle correlation between the block cipher mode of operation, the character encoding of encrypted text, and the response behaviour of a Web Service if an XML message cannot be parsed correctly.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"35 1","pages":"413-422"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78362829","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}
Reputation plays a critical role in managing trust in decentralized systems. Quite a few reputation-based trust functions have been proposed in the literature for many different application domains. However, one cannot always obtain all information required by the trust evaluation process. For example, access control restrictions or high collect costs might limit the ability gather all required records. Thus, one key question is how to analytically quantify the quality of scores computed using incomplete information. In this paper, we start a first effort to answer the above question by studying the following problem: given the existence of certain missing information, what are the worst and best trust scores (i.e., the bounds of trust) a target entity can be assigned? We formulate this problem based on a general model of reputation systems, and examine the monotonicity property of representative trust functions in the literature. We show that most existing trust functions are monotonic in terms of direct missing information about the target of a trust evaluation.
{"title":"Poster: on trust evaluation with missing information in reputation systems","authors":"Xi Gong, Ting Yu, Adam J. Lee","doi":"10.1145/2046707.2093490","DOIUrl":"https://doi.org/10.1145/2046707.2093490","url":null,"abstract":"Reputation plays a critical role in managing trust in decentralized systems. Quite a few reputation-based trust functions have been proposed in the literature for many different application domains. However, one cannot always obtain all information required by the trust evaluation process. For example, access control restrictions or high collect costs might limit the ability gather all required records. Thus, one key question is how to analytically quantify the quality of scores computed using incomplete information. In this paper, we start a first effort to answer the above question by studying the following problem: given the existence of certain missing information, what are the worst and best trust scores (i.e., the bounds of trust) a target entity can be assigned? We formulate this problem based on a general model of reputation systems, and examine the monotonicity property of representative trust functions in the literature. We show that most existing trust functions are monotonic in terms of direct missing information about the target of a trust evaluation.","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"51 1","pages":"773-776"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77200686","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 consider security properties of cryptographic protocols that can be modeled using the notion of trace equivalence. The notion of equivalence is crucial when specifying privacy-type properties, like anonymity, vote-privacy, and unlinkability. In this paper, we give a calculus that is close to the applied pi calculus and that allows one to capture most existing protocols that rely on classical cryptographic primitives. First, we propose a symbolic semantics for our calculus relying on constraint systems to represent infinite sets of possible traces, and we reduce the decidability of trace equivalence to deciding a notion of symbolic equivalence between sets of constraint systems. Second, we develop an algorithm allowing us to decide whether two sets of constraint systems are in symbolic equivalence or not. Altogether, this yields the first decidability result of trace equivalence for a general class of processes that may involve else branches and/or private channels (for a bounded number of sessions).
{"title":"Trace equivalence decision: negative tests and non-determinism","authors":"Vincent Cheval, Hubert Comon-Lundh, S. Delaune","doi":"10.1145/2046707.2046744","DOIUrl":"https://doi.org/10.1145/2046707.2046744","url":null,"abstract":"We consider security properties of cryptographic protocols that can be modeled using the notion of trace equivalence. The notion of equivalence is crucial when specifying privacy-type properties, like anonymity, vote-privacy, and unlinkability.\u0000 In this paper, we give a calculus that is close to the applied pi calculus and that allows one to capture most existing protocols that rely on classical cryptographic primitives. First, we propose a symbolic semantics for our calculus relying on constraint systems to represent infinite sets of possible traces, and we reduce the decidability of trace equivalence to deciding a notion of symbolic equivalence between sets of constraint systems. Second, we develop an algorithm allowing us to decide whether two sets of constraint systems are in symbolic equivalence or not. Altogether, this yields the first decidability result of trace equivalence for a general class of processes that may involve else branches and/or private channels (for a bounded number of sessions).","PeriodicalId":72687,"journal":{"name":"Conference on Computer and Communications Security : proceedings of the ... conference on computer and communications security. ACM Conference on Computer and Communications Security","volume":"22 1","pages":"321-330"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80490560","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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