In recent years, vehicles have evolved into cyberphysical autonomous systems that rely on sensor data from various sources within the vehicle. With the emergence of Vehicle-to-Everything (V2X) technology, the scope of the collaborative functionality in vehicles is now expanding to the inter-vehicular level. To support these modern capabilities, the complexity of the Electronic Control Units (ECUs) and the In-Vehicle Network (IVN) architecture is rapidly increasing. As a result, IVNs are now swarms of devices that communicate safety-critical data. Unfortunately, current vehicular networks lack security, opening the path to numerous cyberattacks. A typical solution for verifying the integrity of multiple devices is swarm attestation. However, in a typical IVN setting, only the Original Equipment Manufacturer (OEM) has access to the legitimate configuration of the ECUs and does not want to disclose this information due to intellectual property and security concerns. Therefore, state- of-the-art swarm attestation schemes, which do not provide privacy guarantees, are unsuitable for IVNs.This paper proposes Secure Privacy Preserving Anonymous Swarm Attestation for In-Vehicle Networks (SPARK), which builds upon a novel group signature scheme to enable privacy-preserving, anonymous, and traceable swarm attestation of IVNs. We validate SPARK through a proof-of-concept implementation using a standardized hardware Trusted Platform Module (TPM 2.0) and representative hardware platforms. The results demonstrate the real-world applicability of SPARK.

In modern large-scale systems comprising multiple heterogeneous devices, the introduction of swarm attestation schemes aims to alleviate the scalability and efficiency issues of traditional single-Prover and single-Verifier attestation. In this paper, we propose PRIVÉ, a privacy-preserving, scalable, and accountable swarm attestation scheme that addresses the limitations of existing solutions. Specifically, we eliminate the assumption of a trusted Verifier, which is not always applicable in real-world scenarios, as the need for the devices to share identifiable information with the Verifier may lead to the expansion of the attack landscape. To this end, we have designed an enhanced variant of the Direct Anonymous Attestation (DAA) protocol, offering traceability and linkability whenever needed. This enables PRIVÉ to achieve anonymous, privacy-preserving attestation while also providing the capability to trace a failed attestation back to the compromised device. To the best of our knowledge, this paper presents the first Universally Composable (UC) security model for swarm attestation accompanied by mathematical UC security proofs, as well as experimental benchmarking results that highlight the efficiency and scalability of the proposed scheme.

Abstract A trusted platform module is identified by its endorsement key, while it uses an attestation key to provide attestation services, for example, signing a set of platform configuration registers, providing a timestamp or certifying another of its keys. This paper addresses the problem of how a certificate authority binds the endorsement and attestation keys together. This is necessary for the authority to be able to reliably certify the attestation key. This key binding also enables the authority to revoke the attestation key should the endorsement key be compromised. We study all of the existing solutions and show that they either do not solve the problem or cannot be implemented with a real trusted platform module (or both). We propose a new solution which addresses this problem. We develop a security model for our solution and provide a rigorous security proof under this model. We have also implemented the solution using a real trusted platform module, and our implementation results show that this solution is feasible and efficient.

Recent advances in Decentralized Digital Identity solutions, revolving around the use of Verifiable Credentials towards identity sovereignty, are centered around Identity Wallets for ensuring that identity data control remains with the user. However, such schemes still lack the capabilities to provide higher Level of Assurance (LoA) guarantees, for identity verification, which restricts their full potential. In this paper, we design and showcase DOOR; a library that enables Identity Wallets to leverage hardware Roots-of-Trust (RoT) for binding user authentication factors to HW-based keys, thus, allowing for both proof of (User) identity and (Wallet) integrity, bringing them in alignment with emerging regulations and standards that require higher LoA for services (e.g. eIDAS). At the same time, we make sure that privacy-enhancing properties like selective-disclosure are fully supported in order to make the Wallet compliant with privacy regulations (e.g. GDPR). To achieve all the above, we have designed an enhanced variant of Attribute-based Direct Anonymous Attestation (DAA-A) crypto protocol for offering anonymity, unlinkability, and unforgeability, while being the first to offer strong guarantees on the Wallet’s integrity when constructing attribute attestations. We formally prove the security properties of DOOR, offered by the underlying crypto primitives used to enable selective disclosure of attributes, by describing their construction while also benchmarking their computational footprint and comparing them with other widespread cryptographic mechanisms (adopted by the standards) in terms of performance, size of the associated verifiable presentations while safeguarding user anonymous authentication and unlinkability.