Simple Public Key Infrastructure Analysis Protocol Analysis and Design

Secure electronic communication is based on secrecy, authentication and authorization. One means of assuring a communication has these properties is to use Public Key Cryptography (PKC). The framework consisting of standards, protocols and instructions that make PKC usable in communication applications is called a Public Key Infrastructure (PKI). This thesis aims at proving the applicability of the Simple Public Key Infrastructure (SPKI) as a means of PKC. The strand space approach of Guttman and Thayer is used to provide an appropriate model for analysis. A Diffie-Hellman strand space model is combined with mixed strand space proof methods for proving the correctness of multiple protocols operating in the same context. The result is the public key mixed strand space model. This model is ideal for the analysis of SPKI applications operating as sub-protocols of an implementing application. This thesis then models the popular Internet Transport Layer Security (TLS) protocol as a public key mixed strand space model. The model includes the integration of SPKI certificates. To accommodate the functionality of SPKI, a new protocol is designed for certificate validation, the Certificate Chain Validation Protocol (CCV). The CCV protocol operates as a sub-protocol to TLS and provides online certificate validation. The security of the TLS protocol integrated with SPKI certificates and subprotocols is then analyzed to prove its security properties

Modeling and Analysis of Advanced Cryptographic Primitives and Security Protocols in Maude-NPA

Tesis por compendio[ES] La herramienta criptográfica Maude-NPA es un verificador de modelos especializado para protocolos de seguridad criptográficos que tienen en cuenta las propiedades algebraicas de un sistema criptográfico. En la literatura, las propiedades criptográficas adicionales han descubierto debilidades de los protocolos de seguridad y, en otros casos, son parte de los supuestos de seguridad del protocolo para funcionar correctamente. Maude-NPA tiene una base teórica en la rewriting logic, la unificación ecuacional y el narrowing para realizar una búsqueda hacia atrás desde un patrón de estado inseguro para determinar si es alcanzable o no. Maude-NPA se puede utilizar para razonar sobre una amplia gama de propiedades criptográficas, incluida la cancelación del cifrado y descifrado, la exponenciación de Diffie-Hellman, el exclusive-or y algunas aproximaciones del cifrado homomórfico. En esta tesis consideramos nuevas propiedades criptográficas, ya sea como parte de protocolos de seguridad o para descubrir nuevos ataques. También hemos modelado diferentes familias de protocolos de seguridad, incluidos los Distance Bounding Protocols or Multi-party key agreement protocolos. Y hemos desarrollado nuevas técnicas de modelado para reducir el coste del análisis en protocolos con tiempo y espacio. Esta tesis contribuye de varias maneras al área de análisis de protocolos criptográficos y muchas de las contribuciones de esta tesis pueden ser útiles para otras herramientas de análisis criptográfico.[CAT] L'eina criptografica Maude-NPA es un verificador de models especialitzats per a protocols de seguretat criptogràfics que tenen en compte les propietats algebraiques d'un sistema criptogràfic. A la literatura, les propietats criptogràfiques addicionals han descobert debilitats dels protocols de seguretat i, en altres casos, formen part dels supòsits de seguretat del protocol per funcionar correctament. Maude-NPA te' una base teòrica a la rewriting lògic, la unificació' equacional i narrowing per realitzar una cerca cap enrere des d'un patró' d'estat insegur per determinar si es accessible o no. Maude-NPA es pot utilitzar per raonar sobre una amplia gamma de propietats criptogràfiques, inclosa la cancel·lació' del xifratge i desxifrat, l'exponenciacio' de Diffie-Hellman, el exclusive-or i algunes aproximacions del xifratge homomòrfic. En aquesta tesi, considerem noves propietats criptogràfiques, ja sigui com a part de protocols de seguretat o per descobrir nous atacs. Tambe' hem modelat diferents famílies de protocols de seguretat, inclosos els Distance Bounding Protocols o Multi-party key agreement protocols. I hem desenvolupat noves tècniques de modelització' de protocols per reduir el cost de l'analisi en protocols amb temps i espai. Aquesta tesi contribueix de diverses maneres a l’àrea de l’anàlisi de protocols criptogràfics i moltes de les contribucions d’aquesta tesi poden ser útils per a altres eines d’anàlisi criptogràfic.[EN] The Maude-NPA crypto tool is a specialized model checker for cryptographic security protocols that take into account the algebraic properties of the cryptosystem. In the literature, additional crypto properties have uncovered weaknesses of security protocols and, in other cases, they are part of the protocol security assumptions in order to function properly. Maude-NPA has a theoretical basis on rewriting logic, equational unification, and narrowing to perform a backwards search from an insecure state pattern to determine whether or not it is reachable. Maude-NPA can be used to reason about a wide range of cryptographic properties, including cancellation of encryption and decryption, Diffie-Hellman exponentiation, exclusive-or, and some approximations of homomorphic encryption. In this thesis, we consider new cryptographic properties, either as part of security protocols or to discover new attacks. We have also modeled different families of security protocols, including Distance Bounding Protocols or Multi-party key agreement protocols. And we have developed new protocol modeling techniques to reduce the time and space analysis effort. This thesis contributes in several ways to the area of cryptographic protocol analysis and many of the contributions of this thesis can be useful for other crypto analysis tools.This thesis would not have been possible without the funding of a set of research projects. The main contributions and derivative works of this thesis have been made in the context of the following projects: - Ministry of Economy and Business of Spain : Project LoBaSS Effective Solutions Based on Logic, Scientific Research under award number TIN2015-69175-C4-1-R, this project was focused on using powerful logic-based technologies to analyze safety-critical systems. - Air Force Office of Scientific Research of United States of America : Project Advanced symbolic methods for the cryptographic protocol analyzer Maude-NPA Scientific Research under award number FA9550-17-1-0286 - State Investigation Agency of Spain : Project FREETech: Formal Reasoning for Enabling and Emerging Technologies Scientific I+D-i Research under award number RTI2018-094403-B-C32Aparicio Sánchez, D. (2022). Modeling and Analysis of Advanced Cryptographic Primitives and Security Protocols in Maude-NPA [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/190915Compendi

Attacking Group Protocols by Refuting Incorrect Inductive Conjectures

Automated tools for finding attacks on flawed security protocols often fail to deal adequately with group protocols. This is because the abstractions made to improve performance on fixed 2 or 3 party protocols either preclude the modelling of group protocols all together, or permit modelling only in a fixed scenario, which can prevent attacks from being discovered. This paper describes Coral, a tool for finding counterexamples to incorrect inductive conjectures, which we have used to model protocols for both group key agreement and group key management, without any restrictions on the scenario. We will show how we used Coral to discover 6 previously unknown attacks on 3 group protocols

Computational soundness for standard assumptions of formal cryptography

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 95-100).This implementation is conceptually simple, and relies only on general assumptions. Specifically, it can be thought of as a 'self-referential' variation on a well-known encryption scheme. 4. Lastly, we show how the computational soundness of the Dolev-Yao model can be maintained even as it is extended to include new operators. In particular, we show how the Diffie-Hellman key-agreement scheme and the computational Diffie-Hellman assumption can be added to the Dolev-Yao model in a computationally sound way.The Dolev-Yao model is a useful and well-known framework in which to analyze security protocols. However, it models the messages of the protocol at a very high level and makes extremely strong assumptions about the power of the adversary. The computational model of cryptography, on the other hand, takes a much lower-level view of messages and uses much weaker assumptions. Despite the large differences between these two models, we have been able to show that there exists a relationship between them. Previous results of ours demonstrate that certain kinds of computational cryptography can result in an equivalence of sorts between the formal and computational adversary. Specifically: * We gave an interpretation to the messages of the Dolev-Yao model in terms of computational cryptography, * We defined a computational security condition, called weak Dolev-Yao non-malleability, that translates the main assumptions of the Dolev-Yao model into the computational setting, and * We demonstrated that this condition is satisfied by a standard definition of computational encryption security called plaintext awareness. In this work, we consider this result and strengthen it in four ways: 1. Firstly, we propose a stronger definition of Dolev-Yao non-malleability which ensures security against a more adaptive adversary. 2. Secondly, the definition of plaintext awareness is considered suspect because it relies on a trusted third party called the random oracle. Thus, we show that our new notion of Dolev-Yao non-malleability is satisfied by a weaker and less troublesome definition for computational encryption called chosen-ciphertext security. 3. Thirdly, we propose a new definition of plaintext-awareness that does not use random oracles, and an implementation.by Jonathan Herzog.Ph.D