QUIC is a secure transport protocol that improves the performance of HTTPS. An initial QUIC handshake that enforces a strict validation of the client's source address requires two round-trips. In this work, we extend QUIC's address validation mechanism by an out-of-band validation token to save one round-trip time during the initial handshake. The proposed token allows sharing an address validation between the QUIC server and trusted entities issuing these tokens. This saves a round-trip time for the address validation. Furthermore, we propose distribution mechanisms for these tokens using DNS resolvers and QUIC connections to other hostnames. Our proposal can save up to 50 of the delay overhead of an initial QUIC handshake. Furthermore, our analytical results indicate that 363.6ms in total can be saved for all connections required to retrieve an average website, if a round-trip time of 90ms is assumed.
@cite_9 does not mitigate a stateless retry during the first connection to a member of a group of hostnames that have an exiting trust-relation with each other. Furthermore, these groups are usually rather small @cite_22 , thus only about 60 , validation tokens obtained from a member of such a group can be considered as trustworthy because these members share secret cryptographic state with each other such as a private key of a X.509 certificate.
@cite_9 @cite_22
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The public key infrastructure-based authentication protocol provides basic security services for the vehicular ad hoc networks (VANETs). However, trust and privacy are still open issues due to the unique characteristics of VANETs. It is crucial to prevent internal vehicles from broadcasting forged messages while simultaneously preserving the privacy of vehicles against the tracking attacks. In this paper, we propose a blockchain-based anonymous reputation system (BARS) to establish a privacy-preserving trust model for VANETs. The certificate and revocation transparency is implemented efficiently with the proofs of presence and absence based on the extended blockchain technology. The public keys are used as pseudonyms in communications without any information about real identities for conditional anonymity. In order to prevent the distribution of forged messages, a reputation evaluation algorithm is presented relying on both direct historical interactions and indirect opinions about vehicles. A set of experiments is conducted to evaluate BARS in terms of security, validity, and performance, and the results show that BARS is able to establish a trust model with transparency, conditional anonymity, efficiency, and robustness for VANETs. The semantics of online authentication in the web are rather straightforward: if Alice has a certificate binding Bob's name to a public key, and if a remote entity can prove knowledge of Bob's private key, then (barring key compromise) that remote entity must be Bob. However, in reality, many websites' and the majority of the most popular ones-are hosted at least in part by third parties such as Content Delivery Networks (CDNs) or web hosting providers. Put simply: administrators of websites who deal with (extremely) sensitive user data are giving their private keys to third parties. Importantly, this sharing of keys is undetectable by most users, and widely unknown even among researchers. In this paper, we perform a large-scale measurement study of key sharing in today's web. We analyze the prevalence with which websites trust third-party hosting providers with their secret keys, as well as the impact that this trust has on responsible key management practices, such as revocation. Our results reveal that key sharing is extremely common, with a small handful of hosting providers having keys from the majority of the most popular websites. We also find that hosting providers often manage their customers' keys, and that they tend to react more slowly yet more thoroughly to compromised or potentially compromised keys. The ubiquity of the Internet has led to increased resource sharing between large numbers of users in widely-disparate administrative domains. Unfortunately, traditional identity-based solutions to the authorization problem do not allow for the dynamic establishment of trust, and thus cannot be used to facilitate interactions between previously-unacquainted parties. Furthermore, the management of identity-based systems becomes burdensome as the number of users in the system increases. To address this gap between the needs of open computing systems and existing authorization infrastructures, researchers have begun to investigate novel attribute-based access control (ABAC) systems based on techniques such as trust negotiation and other forms of distributed proving. To date, research in these areas has been largely theoretical and has produced many important foundational results. However, if these techniques are to be safely deployed in practice, the systems-level barriers hindering their adoption must be overcome. In this thesis, we show that safely and securely adopting decentralized ABAC approaches to authorization is not simply a matter of implementation and deployment, but requires careful consideration of both formal properties and practical issues. To this end, we investigate a progression of important questions regarding the safety analysis, deployment, implementation, and optimization of these types of systems. We first show that existing ABAC theory does not properly account for the asynchronous nature of open systems, which allows attackers to subvert these systems by forcing decisions to be made using inconsistent system states. To address this, we develop provably-secure and lightweight consistency enforcement mechanisms suitable for use in trust negotiation and distributed proof systems. We next focus on deployment issues, and investigate how user interactions can be audited in the absence of concrete user identities. We develop the technique of virtual fingerprinting, which can be used to accomplish this task without adversely affecting the scalability of audit systems. Lastly, we present TrustBuilder2, which is the first fully-configurable framework for trust negotiation. Within this framework, we examine availability problems associated with the trust negotiation process and develop a novel approach to policy compliance checking that leverages an efficient pattern-matching approach to outperform existing techniques by orders of magnitude. QUIC is a performance-optimized secure transport protocol and a building block of the upcoming HTTP 3 standard. To protect against denial-of-service attacks, QUIC servers need to validate the IP addresses claimed by their clients. So far, the QUIC protocol conducts address validation for each hostname separately using validation tokens. In this work, we review this practice and introduce a new QUIC transport parameter to allow a shared address validation across hostnames. This parameter indicates to the client, that an issued validation token can be used to abbreviate the address validation when connecting to specific other hostnames. Based on trust-relations between real-world hostnames we evaluate the performance benefits of our proposal. Our results suggest that a shared address validation saves a round-trip time on almost 60 of the required handshakes to different hosts during the first loading of an average website. Assuming a typical transatlantic connection with a round-trip time of 90ms. We find that deploying our proposal reduces the delay overhead to establish all required connections for an average website by 142.2ms.