{"title":"Process algebra and non-interference","authors":"P. Ryan, Steve A. Schneider","doi":"10.1109/CSFW.1999.779775","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779775","url":null,"abstract":"The information security community has long debated the exact definition of the term \"security\". Even if we focus on the more modest notion of confidentiality the precise definition remains controversial. In their seminal paper, Goguen and Meseguer (1982) took an important step towards a formalisation of the notion of absence of information flow with the concept of non-interference. This too was found to have problems and limitations, particularly when applied to systems displaying non-determinism which led to a proliferation of refinements of this notion and there is still no consensus as to which of these is \"correct\". We show that this central concept in information security is closely related to a central concept of computer science: that of the equivalence of systems. The notion of non-interference depends ultimately on our notion of process equivalence. However what constitutes the equivalence of two processes is itself a deep and controversial question in computer science with a number of distinct definitions proposed in the literature. We illustrate how several of the leading candidates for a definition of non-interference mirror notions of system equivalence. Casting these security concepts in a process algebraic framework clarifies the relationship between them and allows many results to be carried over regarding, for example, composition and unwinding. We also outline some generalisations of non-interference to handle partial and conditional information flows.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114642495","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":"I/O automaton models and proofs for shared-key communication systems","authors":"N. Lynch","doi":"10.1109/CSFW.1999.779759","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779759","url":null,"abstract":"The combination of two security protocols, a simple shared-key communication protocol and the Diffie-Hellman key distribution protocol, is modeled formally and proved correct. The modeling is based on the I/O automaton model for distributed algorithms, and the proofs are based on invariant assertions, simulation relations, and compositional reasoning. Arguments about the cryptosystems are handled separately from arguments about the protocols.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115741863","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}
F. Javier, Thayer, Fábrega, C. Jonathan, Herzog, Joshua
{"title":"Mixed strand spaces","authors":"F. Javier, Thayer, Fábrega, C. Jonathan, Herzog, Joshua","doi":"10.1109/CSFW.1999.779763","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779763","url":null,"abstract":"Strand space analysis is a method for stating and proving correctness properties for cryptographic protocols. In this paper we apply the same method to the related problem of mixed protocols, and show that a protocol can remain correct even when used in combination with a range of other protocols. We illustrate the method with the familiar Otway-Rees protocol. We identify a simple and easily verified characteristic of protocols, and show that the Otway-Rees protocol remains correct even when used in combination with other protocols that have this characteristic. We also illustrate this method on the Neuman-Stubblebine protocol. This protocol has two parts, an authentication protocol (I) in which a key distribution center creates and distributes a Kerberos-like key, and a reauthentication protocol (II) in which a client resubmits a ticket containing that key. The re-authentication protocol II is known to be flawed. We show that in the presence of protocol II, there are also attacks against protocol I. We then define a variant of protocol II, and prove an authentication property of I that holds even in combination with the modified II.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"6 5p1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113957548","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":"Honest functions and their application to the analysis of cryptographic protocols","authors":"Alfred P. Maneki","doi":"10.1109/CSFW.1999.779764","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779764","url":null,"abstract":"J.D. Guttman, et al. (1998) have introduced \"strand spaces\" as a technique for describing and analyzing cryptographic protocols (i.e. schemes for exchanging messages between legitimate agents in a communications system for purposes of authentication or establishing session keys). The strands of such a protocol are directly mapped to traces of the messages which are transmitted and received by each agent. Strands may also be associated with the possible traces of a penetrator. J.D. Guttman, et al. (1998) use simple graph theoretic constructions to describe the underlying relations between legitimate agents and the penetrator. These researchers also develop an \"algebra\" for the set of all possible messages which may be transmitted in a given cryptographic protocol. They have successfully used strand spaces to prove correctness properties of several cryptographic protocols. In this paper we extend the theory of strand spaces to include a broad class of cryptographic protocols which could not be analyzed in the original framework provided by Guttman, et al. This class includes the TMN (Roscose's version) and SSHV2 protocols, i.e., protocols which use the exclusive-or and exponential functions for message generation. In an intuitive manner we define the class of \"honest\" functions and extend the theory to include these functions. We conclude this paper with an analysis of the TMN protocol.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117223045","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":"Formalization and proof of secrecy properties","authors":"D. Volpano","doi":"10.1109/CSFW.1999.779765","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779765","url":null,"abstract":"After looking at the security literature, you will find secrecy is formalized in different ways, depending on the application. Applications have threat models that influence our choice of secrecy properties. A property may be reasonable in one context and completely unsatisfactory in another if other threats exist. The primary goal of this paper is to foster discussion on what sorts of secrecy properties are appropriate for different applications and to investigate what they have in common. We also want to explore what is meant by secrecy in different contexts. Perhaps there is enough overlap among our threat models that we can begin to identify some key secrecy properties for wider application. Currently, secrecy is treated in rather ad hoc ways. With some agreement among calculi for expressing protocols and systems, we might even be able to use one another's proof techniques for proving secrecy.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127831457","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":"Safe simplifying transformations for security protocols or not just the Needham Schroeder pubic key protocol","authors":"M. Hui, G. Lowe","doi":"10.1109/CSFW.1999.779760","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779760","url":null,"abstract":"Recent techniques for analyzing security protocols have tended to concentrate upon the small protocols that are typically found in the academic literature. However there is a huge gulf between these and most large commercial protocols: the latter typically have many more fields, and much higher levels of nested encryption. As a result, existing techniques are difficult to apply directly to these large protocols. In this paper we develop the notion of safe simplifying transformations: transformations that have the property of preserving insecurities; the effect of such transformations is that if we can verify the transformed protocol, then we will have verified the original protocol. We identify a number of such safe simplifying transformations, and use them in the analysis of a commercial protocol.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121663459","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":"A formal framework and evaluation method for network denial of service","authors":"C. Meadows","doi":"10.1109/CSFW.1999.779758","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779758","url":null,"abstract":"Denial of service is becoming a growing concern. As our systems communicate more and more with others that we know less and less, they become increasingly vulnerable to hostile intruders who may take advantage of the very protocols intended for the establishment and authentication of communication to tie up our resources and disable our servers. Since these attacks occur before parties are authenticated to each other we cannot rely upon enforcement of the appropriate access control policy to protect us. Instead we must build our defenses, as much as possible, into the protocols themselves. This paper shows how some principles that have already been used to make protocols more resistant to denial of service can be formalized, and indicates the ways in which existing cryptographic protocol analysis tools could be modified to operate within this formal framework.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131074222","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":"What is intransitive noninterference?","authors":"A. W. Roscoe, Michael Goldsmith","doi":"10.1109/CSFW.1999.779776","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779776","url":null,"abstract":"The term \"intransitive noninterference\" refers to the information flow properties required of systems like downgraders, in which it may be legitimate for information to flow indirectly, between two users but not directly. We examine the usual definition of this property in terms of a modified purge function, and show that this is a distinctly weaker property than an alternative we derive from considerations of determinism.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"201 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124931150","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":"Decision procedures for the analysis of cryptographic protocols by logics of belief","authors":"D. Monniaux","doi":"10.1109/CSFW.1999.779761","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779761","url":null,"abstract":"Belief-logic deductions are used in the analysis of cryptographic protocols. We show a new method to decide such logics. In addition to the familiar BAN logic, it is also applicable to the more advanced versions of protocol security logics, and GNY in particular; and it employs an efficient forward-chaining algorithm the completeness and termination of which are proved. Theoretic proofs, implementation decisions and results are discussed.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124369182","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":"Secure composition of insecure components","authors":"Peter Sewell, J. Vitek","doi":"10.1109/CSFW.1999.779769","DOIUrl":"https://doi.org/10.1109/CSFW.1999.779769","url":null,"abstract":"Software systems are becoming heterogeneous: instead of a small number of large programs from well-established sources, a user's desktop may now consist of many smaller components that interact in intricate ways. Some components will be down-loaded from the network from sources that are only partially trusted. A user would like to know that a number of security properties hold, e.g., that personal data is not leaked to the net, but it is typically infeasible to verify that such components are well behaved. Instead they must be executed in a secure environment, or wrapper, that provides fine grain control of the allowable interactions between them and between components and other system resources. We study such wrappers, focusing on how they can be expressed in a way that enables their security properties to be stated and proved rigorously. We introduce a model programming language, the box-/spl pi/ calculus that supports composition of software components and the enforcement of security policies. Several example wrappers are expressed using the calculus: we explore the delicate security properties they guarantee.","PeriodicalId":374159,"journal":{"name":"Proceedings of the 12th IEEE Computer Security Foundations Workshop","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123054173","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}