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200
Compositional Model Checking
, 1999
"... We describe a method for reducing the complexity of temporal logic model checking in systems composed of many parallel processes. The goal is to check properties of the components of a system and then deduce global properties from these local properties. The main difficulty with this type of approac ..."
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Cited by 2407 (62 self)
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We describe a method for reducing the complexity of temporal logic model checking in systems composed of many parallel processes. The goal is to check properties of the components of a system and then deduce global properties from these local properties. The main difficulty with this type of approach is that local properties are often not preserved at the global level. We present a general framework for using additional interface processes to model the environment for a component. These interface processes are typically much simpler than the full environment of the component. By composing a component with its interface processes and then checking properties of this composition, we can guarantee that these properties will be preserved at the global level. We give two example compositional systems based on the logic CTL*.
Reconciling Two Views of Cryptography (The Computational Soundness of Formal Encryption)
, 2000
"... Two distinct, rigorous views of cryptography have developed over the years, in two mostly separate communities. One of the views relies on a simple but effective formal approach; the other, on a detailed computational model that considers issues of complexity and probability. ..."
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Cited by 333 (18 self)
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Two distinct, rigorous views of cryptography have developed over the years, in two mostly separate communities. One of the views relies on a simple but effective formal approach; the other, on a detailed computational model that considers issues of complexity and probability.
Architectural Support for Copy and Tamper Resistant Software
, 2000
"... Implementing copy protection on software is a difficult problem that has resisted a satisfactory solution for many years. This paper proposes a set of features that allows a machine to execute XOM code: code where neither the instructions or the data are visible to entities outside the running proce ..."
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Cited by 211 (5 self)
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Implementing copy protection on software is a difficult problem that has resisted a satisfactory solution for many years. This paper proposes a set of features that allows a machine to execute XOM code: code where neither the instructions or the data are visible to entities outside the running process. To support XOM code we use a machine that supports internal compartments, where a process in one compartment cannot read data from another compartment. All data that leaves the machine is encrypted, since we assume secure compartments cannot be guaranteed by anything outside the machine. The design of this machine poses some interesting tradeoffs between security, efficiency and flexibility. We explore some of the potential security issues as one pushes the machine to become more efficient and flexible. Our analysis indicates, while not cheap, it is possible to create a normal multitasking machine where nearly all applications can be run in XOM mode. While a virtual XOM machine is possible, the underlying hardware needs to support a unique private key, asymmetric decryption, private memory, fast symmetric ciphers, and traps on cache misses for efficient operation.
Protocol insecurity with finite number of sessions is NPcomplete
 Theoretical Computer Science
, 2001
"... We investigate the complexity of the protocol insecurity problem for a finite number of sessions (fixed number of interleaved runs). We show that this problem is NPcomplete with respect to a DolevYao model of intruders. The result does not assume a limit on the size of messages and supports nonat ..."
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Cited by 148 (12 self)
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We investigate the complexity of the protocol insecurity problem for a finite number of sessions (fixed number of interleaved runs). We show that this problem is NPcomplete with respect to a DolevYao model of intruders. The result does not assume a limit on the size of messages and supports nonatomic symmetric encryption keys. We also prove that in order to build an attack with a fixed number of sessions the intruder needs only to forge messages of linear size, provided that they are represented as dags.
A metanotation for protocol analysis
 in: Proc. CSFW’99
, 1999
"... Most formal approaches to security protocol analysis are based on a set of assumptions commonly referred to as the “DolevYao model. ” In this paper, we use a multiset rewriting formalism, based on linear logic, to state the basic assumptions of this model. A characteristic of our formalism is the w ..."
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Cited by 142 (33 self)
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Most formal approaches to security protocol analysis are based on a set of assumptions commonly referred to as the “DolevYao model. ” In this paper, we use a multiset rewriting formalism, based on linear logic, to state the basic assumptions of this model. A characteristic of our formalism is the way that existential quantification provides a succinct way of choosing new values, such as new keys or nonces. We define a class of theories in this formalism that correspond to finitelength protocols, with a bounded initialization phase but allowing unboundedly many instances of each protocol role (e.g., client, server, initiator, or responder). Undecidability is proved for a restricted class of these protocols, and PSPACEcompleteness is claimed for a class further restricted to have no new data (nonces). Since it is a fragment of linear logic, we can use our notation directly as input to linear logic tools, allowing us to do proof search for attacks with relatively little programming effort, and to formally verify protocol transformations and optimizations. 1
Classification of Security Properties (Part I: Information Flow)
, 2001
"... In the recent years, many formalizations of security properties have been proposed, most of which are based on different underlying models and are consequently difficult to compare. A classification of security properties is thus of interest for understanding the relationships among different defini ..."
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Cited by 90 (16 self)
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In the recent years, many formalizations of security properties have been proposed, most of which are based on different underlying models and are consequently difficult to compare. A classification of security properties is thus of interest for understanding the relationships among different definitions and for evaluating the relative merits. In this paper, many noninterferencelike properties proposed for computer security are classified and compared in a unifying framework. The resulting taxonomy is evaluated through some case studies of access control in computer systems. The approach has been mechanized, resulting in the tool CoSeC. Various extensions (e.g., the application to cryptographic protocol analysis) and open problems are discussed. This paper
A Formal Framework and Evaluation Method for Network Denial of Service
, 1999
"... Denial of serviceisbecoming 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 ..."
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Cited by 86 (5 self)
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Denial of serviceisbecoming 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 beforeparties are authenticatedtoeach other, we cannot rely upon enforcement of the appropriate access control policy to protect us #as is recommended in the classic work of Gligor and Millen in #5, 18, 19##. 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 moreresistant to denial of servicecan be formalized, and indicates the ways in which existing cryptographic protocol analysis tools could be modi#ed to operate within this formal framework. 1 Introduction Denial of service is becoming a growing c...
On the Reachability Problem in Cryptographic Protocols
, 2000
"... We study the verification of secrecy and authenticity properties for cryptographic protocols which rely on symmetric shared keys. The verification can be reduced to check whether a certain parallel program which models the protocol and the specification can reach an erroneous state while interacting ..."
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Cited by 84 (0 self)
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We study the verification of secrecy and authenticity properties for cryptographic protocols which rely on symmetric shared keys. The verification can be reduced to check whether a certain parallel program which models the protocol and the specification can reach an erroneous state while interacting with the environment. Assuming finite principals, we present a simple decision procedure for the reachability problem which is based on a `symbolic' reduction system.
Kerberos version IV: Inductive analysis of the secrecy goals
 Computer Security — ESORICS 98, LNCS 1485
, 1998
"... Abstract. An operational model of cryptoprotocols is tailored to the detailed analysis of the secrecy goals accomplished by Kerberos Version IV. The model is faithful to the specification of the protocol presented by the MIT technical plan [14] — e.g. timestamping, double session key delivery mech ..."
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Cited by 73 (27 self)
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Abstract. An operational model of cryptoprotocols is tailored to the detailed analysis of the secrecy goals accomplished by Kerberos Version IV. The model is faithful to the specification of the protocol presented by the MIT technical plan [14] — e.g. timestamping, double session key delivery mechanism are included. It allows an eavesdropper to exploit the shared keys of compromised agents, and admits the accidental loss of expired session keys. Confidentiality is expressed from the viewpoint of each party involved in a protocol run, with particular attention to the assumptions the party relies on. If such assumptions are unrealistic, they highlight weaknesses of the protocol. This is particularly so from the viewpoint of the responder: the model suggests and proves a reasonable correction.
Athena: a new efficient automatic checker for security protocol analysis
 In Proceedings of the Twelth IEEE Computer Security Foundations Workshop
, 1999
"... We propose an efficient automatic checking algorithm, Athena, for analyzing security protocols. Athena incorporates a logic that can express security properties including authentication, secrecy and properties related to electronic commerce. We have developed an automatic procedure for evaluating we ..."
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Cited by 72 (1 self)
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We propose an efficient automatic checking algorithm, Athena, for analyzing security protocols. Athena incorporates a logic that can express security properties including authentication, secrecy and properties related to electronic commerce. We have developed an automatic procedure for evaluating wellformed formulae in this logic. For a wellformed formula, if the evaluation procedure terminates, it will generate a counterexample if the formula is false, or provide a proof if the formula is true. Even when the procedure does not terminate when we allow any arbitrary configurations of the protocol execution, (for example, any number of initiators and responders), termination could be forced by bounding the number of concurrent protocol runs and the length of messages, as is done in most existing model checkers. Athena also exploits several state space reduction techniques. It is based on an extension of the recently proposed Strand Space Model [25] which captures exact causal relation information. Together with backward search and other techniques, Athena naturally avoids the state space explosion problem commonly caused by asynchronous composition and symmetry redundancy. Athena also has the advantage that it can easily incorporate results from theorem proving through unreachability theorems. By using the unreachability theorems, it can prune the state space at an early stage, hence, reduce the state space explored and increase the likelyhood of termination. As shown in our experiments, these techniques dramatically reduce the state space that needs to be explored.