Analysis of Selected Security Protocols

Předmětem této diplomové práce je studium dostupných bezpečnostních protokolů a nástrojů sloužících k jejich verifikaci. První část práce se krátce věnuje popisu pojmů souvisejících s oblastí bezpečnostních protokolů a verifikačních logik. Druhá část již přímo uvádí jednotlivé protokoly spolu s nalezenými útoky a chybami v návrhu. V další kapitole jsou detailněji popsány nejdůležitější nástroje pro automatickou analýzu bezpečnostních protokolů. Hlavní část práce se zabývá verifikací vybraných bezpečnostních protokolů ve zvoleném nástroji Scyther. Na závěr jsou uvedeny příklady víceprotokolových útoků spolu s přehledovou tabulkou.The subject of this thesis is to study available security protocols and tools for their verification. The first part is devoted to briefly describe the concepts related to the area of security protocols and verification logics. The second part directly lists various protocols, along with attacks and errors found in design. Next chapter describes the most important tools for automatic analysis of security protocols in more detail. The main part deals with verification of security protocols selected in the chosen tool called Scyther. In conclusion, examples of multiprotocol attacks along with a summary table are displayed.

Securing Deployed Cryptographic Systems

In 2015 more than 150 million records and $400 billion were lost due to publicly-reported criminal and nation-state cyberattacks in the United States alone. The failure of our existing security infrastructure motivates the need for improved technologies, and cryptography provides a powerful tool for doing this. There is a misperception that the cryptography we use today is a "solved problem" and the real security weaknesses are in software or other areas of the system. This is, in fact, not true at all, and over the past several years we have seen a number of serious vulnerabilities in the cryptographic pieces of systems, some with large consequences. This thesis will discuss three aspects of securing deployed cryptographic systems. We will first explore the evaluation of systems in the wild, using the example of how to efficiently and effectively recover user passwords submitted over TLS encrypted with RC4, with applications to many methods of web authentication as well as the popular IMAP protocol for email. We will then address my work on developing tools to design and create cryptographic systems and bridge the often large gap between theory and practice by introducing AutoGroup+, a tool that automatically translates cryptographic schemes from the mathematical setting used in the literature to that typically used in practice, giving both a secure and optimal output. We will conclude with an exploration of how to actually build real world deployable systems by discussing my work on developing decentralized anonymous credentials in order to increase the security and deployability of existing anonymous credentials systems