43,457 research outputs found
Verifying security protocols by knowledge analysis
This paper describes a new interactive method to analyse knowledge of participants involved in security protocols and further to verify the correctness of the protocols. The method can detect attacks and flaws involving interleaving sessions besides normal attacks. The implementation of the method in a generic theorem proving environment, namely Isabelle, makes the verification of protocols mechanical and efficient; it can verify a medium-sized security protocol in less than ten seconds. As an example, the paper finds the flaw in the Needham-Schroeder public key authentication protocol and proves the secure properties and guarantees of the protocol with Lowe's fix to show the effectiveness of this method
Computationally Complete Symbolic Attacker in Action
We show that the recent technique of computationally complete symbolic attackers proposed by Bana and Comon-Lundh [POST 2012] for computationally sound verification of security protocols is powerful enough to verify actual protocols. In their work, Bana and Comon-Lundh presented only the general framework, but they did not introduce sufficiently many axioms to actually prove protocols.
We present a set of axioms -- some generic axioms that are computationally sound for all PPT algorithms, and two specific axioms that are sound for CCA2 secure encryptions -- and illustrate the power of this technique by giving the first computationally sound verification (secrecy and authentication) via symbolic attackers of the NSL Protocol that does not need any further restrictive assumptions about the computational implementation.
The axioms are entirely modular, not particular to the NSL protocol
ASICS: Authenticated Key Exchange Security Incorporating Certification Systems
Most security models for authenticated key exchange (AKE) do not explicitly model the associated certification system, which includes the certification authority and its behaviour. However, there are several well-known and realistic attacks on AKE protocols which exploit various forms of malicious key registration and which therefore lie outside the scope of these models. We provide the first systematic analysis of AKE security incorporating certification systems. We define a family of security models that, in addition to allowing different sets of standard AKE adversary queries, also permit the adversary to register arbitrary bitstrings as keys. For this model family, we prove generic results that enable the design and verification of protocols that achieve security even if some keys have been produced maliciously. Our approach is applicable to a wide range of models and protocols; as a concrete illustration of its power, we apply it to the CMQV protocol in the natural strengthening of the eCK model to the ASICS setting
Machine-Checked Formalisation and Verification of Cryptographic Protocols
PhD ThesisAiming for strong security assurance, researchers in academia and industry focus
their interest on formal verification of cryptographic constructions. Automatising
formal verification has proved itself to be a very difficult task, where the main
challenge is to support generic constructions and theorems, and to carry out the
mathematical proofs.
This work focuses on machine-checked formalisation and automatic verification of cryptographic protocols. One aspect we covered is the novel support for
generic schemes and real-world constructions among old and novel protocols: key exchange schemes (Simple Password Exponential Key Exchange, SPEKE), commitment
schemes (with the popular Pedersen scheme), sigma protocols (with the Schnorrās
zero-knowledge proof of knowledge protocol), and searchable encryption protocols
(Sophos).
We also investigated aspects related to the reasoning of simulation based proofs,
where indistinguishability of two different algorithms by any adversary is the crucial
point to prove privacy-related properties. We embedded information-flow techniques
into the EasyCrypt core language, then we show that our effort not only makes some
proofs easier and (sometimes) fewer, but is also more powerful than other existing
techniques in particular situations
Provably correct Java implementations of Spi Calculus security protocols specifications
Spi Calculus is an untyped high level modeling language for security protocols, used for formal protocols specification and verification. In this paper, a type system for the Spi Calculus and a translation function are formally defined, in order to formalize the refinement of a Spi Calculus specification into a Java implementation. The Java implementation generated by the translation function uses a custom Java library. Formal conditions on such library are stated, so that, if the library implementation code satisfies such conditions, then the generated Java implementation correctly simulates the Spi Calculus specification. A verified implementation of part of the custom library is further presente
Temporal verification in secure group communication system design
The paper discusses an experience in using a real-time UML/SysML profile and a formal verification toolkit to check a secure group communication system against temporal requirements. A generic framework is proposed and specialized for hierarchical groups
Automated Cryptographic Analysis of the Pedersen Commitment Scheme
Aiming for strong security assurance, recently there has been an increasing
interest in formal verification of cryptographic constructions. This paper
presents a mechanised formal verification of the popular Pedersen commitment
protocol, proving its security properties of correctness, perfect hiding, and
computational binding. To formally verify the protocol, we extended the theory
of EasyCrypt, a framework which allows for reasoning in the computational
model, to support the discrete logarithm and an abstraction of commitment
protocols. Commitments are building blocks of many cryptographic constructions,
for example, verifiable secret sharing, zero-knowledge proofs, and e-voting.
Our work paves the way for the verification of those more complex
constructions.Comment: 12 pages, conference MMM-ACNS 201
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