Performance Evaluations of Cryptographic Protocols Verification Tools Dealing with Algebraic Properties

International audienceThere exist several automatic verification tools of cryptographic protocols, but only few of them are able to check protocols in presence of algebraic properties. Most of these tools are dealing either with Exclusive-Or (XOR) and exponentiation properties, so-called Diffie-Hellman (DH). In the last few years, the number of these tools increased and some existing tools have been updated. Our aim is to compare their performances by analysing a selection of cryptographic protocols using XOR and DH. We compare execution time and memory consumption for different versions of the following tools OFMC, CL-Atse, Scyther, Tamarin, TA4SP, and extensions of ProVerif (XOR-ProVerif and DH-ProVerif). Our evaluation shows that in most of the cases the new versions of the tools are faster but consume more memory. We also show how the new tools: Tamarin, Scyther and TA4SP, can be compared to previous ones. We also discover and understand for the protocol IKEv2-DS a difference of modelling by the authors of different tools, which leads to different security results. Finally, for Exclusive-Or and Diffie-Hellman properties, we construct two families of protocols P xori and P dhi that allow us to clearly see for the first time the impact of the number of operators and variables in the tools' performances

Enhancing IPsec Performance in Mobile IPv6 Using Elliptic Curve Cryptography

Internet has become indispensable to the modern society nowadays. Due to the dynamic nature of human activities, the evolving mobile technology has played a significant role and it is reflected in the exponential growth of the number of mobile users globally. However, the characteristic of the Internet as an open network made it vulnerable to various malicious activities. To secure communication at network layer, IETF recommended IPsec as a security feature. Mobile IPv6 as the successor of the current mobile technology, Mobile IPv4, also mandated the use of IPsec. However, since IPsec is a set of security algorithm, it has several well-known weaknesses such as bootstrapping issue when generating a security association as well as complex key exchange mechanism. It is a well-known fact that IPsec has a high overhead especially when implemented on Mobile IPv6 and used on limited energy devices such as mobile devices. This paper aims to enhance the IPsec performance by substituting the existing key exchange algorithm with a lightweight elliptic curve algorithm. The experiments managed to reduce the delay of IPsec in Mobile IPv6 by 67% less than the standard implementation

Measuring small subgroup attacks against Diffie-Hellman

Several recent standards, including NIST SP 800- 56A and RFC 5114, advocate the use of “DSA” parameters for Diffie-Hellman key exchange. While it is possible to use such parameters securely, additional validation checks are necessary to prevent well-known and potentially devastating attacks. In this paper, we observe that many Diffie-Hellman implementations do not properly validate key exchange inputs. Combined with other protocol properties and implementation choices, this can radically decrease security. We measure the prevalence of these parameter choices in the wild for HTTPS, POP3S, SMTP with STARTTLS, SSH, IKEv1, and IKEv2, finding millions of hosts using DSA and other non-“safe” primes for Diffie-Hellman key exchange, many of them in combination with potentially vulnerable behaviors. We examine over 20 open-source cryptographic libraries and applications and observe that until January 2016, not a single one validated subgroup orders by default. We found feasible full or partial key recovery vulnerabilities in OpenSSL, the Exim mail server, the Unbound DNS client, and Amazon’s load balancer, as well as susceptibility to weaker attacks in many other applications

Measuring And Securing Cryptographic Deployments

This dissertation examines security vulnerabilities that arise due to communication failures and incentive mismatches along the path from cryptographic algorithm design to eventual deployment. I present six case studies demonstrating vulnerabilities in real-world cryptographic deployments. I also provide a framework with which to analyze the root cause of cryptographic vulnerabilities by characterizing them as failures in four key stages of the deployment process: algorithm design and cryptanalysis, standardization, implementation, and endpoint deployment. Each stage of this process is error-prone and influenced by various external factors, the incentives of which are not always aligned with security. I validate the framework by applying it to the six presented case studies, tracing each vulnerability back to communication failures or incentive mismatches in the deployment process. To curate these case studies, I develop novel techniques to measure both existing and new cryptographic attacks, and demonstrate the widespread impact of these attacks on real-world systems through measurement and cryptanalysis. While I do not claim that all cryptographic vulnerabilities can be described with this framework, I present a non-trivial (in fact substantial) number of case studies demonstrating that this framework characterizes the root cause of failures in a diverse set of cryptographic deployments

Using Large-Scale Empirical Methods to Understand Fragile Cryptographic Ecosystems

Cryptography is a key component of the security of the Internet. Unfortunately, the process of using cryptography to secure the Internet is fraught with failure. Cryptography is often fragile, as a single mistake can have devastating consequences on security, and this fragility is further complicated by the diverse and distributed nature of the Internet. This dissertation shows how to use empirical methods in the form of Internet-wide scanning to study how cryptography is deployed on the Internet, and shows this methodology can discover vulnerabilities and gain insights into fragile cryptographic ecosystems that are not possible without an empirical approach. I introduce improvements to ZMap, the fast Internet-wide scanner, that allow it to fully utilize a 10 GigE connection, and then use Internet-wide scanning to measure cryptography on the Internet. First, I study how Diffie-Hellman is deployed, and show that implementations are fragile and not resilient to small subgroup attacks. Next, I measure the prevalence of ``export-grade'' cryptography. Although regulations limiting the strength of cryptography that could be exported from the United States were lifted in 1999, Internet-wide scanning shows that support for various forms of export cryptography remains widespread. I show how purposefully weakening TLS to comply with these export regulations led to the FREAK, Logjam, and DROWN vulnerabilities, each of which exploits obsolete export-grade cryptography to attack modern clients. I conclude by discussing how empirical cryptography improved protocol design, and I present further opportunities for empirical research in cryptography.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/149809/1/davadria_1.pd

L-band Digital Aeronautical Communications System (LDACS) draft-ietf-raw-ldacs-07

This document provides an overview of the architecture of the L-band Digital Aeronautical Communications System (LDACS), which provides a secure, scalable and spectrum efficient terrestrial data link for civil aviation. LDACS is a scheduled, reliable multi-application cellular broadband system with support for IPv6. LDACS shall provide a data link for IP network-based aircraft guidance. High reliability and availability for IP connectivity over LDACS are therefore essential