Giovanni Mazzeo

Giovanni Maria Cristiano, Salvatore D'Antonio, Jonah Giglio et al.

The growing scalability demand of public Blockchains led to the rise of Layer-2 solutions, such as Rollups. Rollups improve transaction throughput by processing operations off-chain and posting the results on-chain. A critical component in Rollups is the Sequencer, responsible for receiving, ordering and batching transactions before they are submitted to the Layer-1 blockchain. While essential, the centralized nature of the Sequencer makes it vulnerable to attacks, such as censorship, transaction manipulation and tampering. To enhance its security, there are solutions in the literature that shield the Sequencer inside a Trusted Execution Environment (TEE). However, the attestation of TEEs introduces additional centralization, which is in contrast with the core Blockchain principle. In this paper, we propose a TEE-secured Sequencer equipped with a decentralized attestation mechanism. We outline the design and implementation of our solution, covering the system architecture, TEE integration, and the decentralization of the attestation process. Additionally, we present an experimental evaluation conducted on a realistic Rollup testnet. Our results show that this approach strengthens Sequencer integrity without sacrificing compatibility or deployability in existing Layer-2 architectures.

Lorenzo Andolfo, Luigi Coppolino, Salvatore D'Antonio et al.

The majority of financial organizations managing confidential data are aware of security threats and leverage widely accepted solutions (e.g., storage encryption, transport-level encryption, intrusion detection systems) to prevent or detect attacks. Yet these hardening measures do little to face even worse threats posed on data-in-use. Solutions such as Homomorphic Encryption (HE) and hardware-assisted Trusted Execution Environment (TEE) are nowadays among the preferred approaches for mitigating this type of threat. However, given the high-performance overhead of HE, financial institutions -- whose processing rate requirements are stringent -- are more oriented towards TEE-based solutions. The X-Margin Inc. company, for example, offers secure financial computations by combining the Intel SGX TEE technology and HE-based Zero-Knowledge Proofs, which shield customers' data-in-use even against malicious insiders, i.e., users having privileged access to the system. Despite such a solution offers strong security guarantees, it is constrained by having to trust Intel and by the SGX hardware extension availability. In this paper, we evaluate a new frontier for X-Margin, i.e., performing privacy-preserving credit risk scoring via an emerging cryptographic scheme: Functional Encryption (FE), which allows a user to only learn a function of the encrypted data. We describe how the X-Margin application can benefit from this innovative approach and -- most importantly -- evaluate its performance impact.

Luigi De Simone, Giovanni Mazzeo

A promising approach for designing critical embedded systems is based on virtualization technologies and multi-core platforms. These enable the deployment of both real-time and general-purpose systems with different criticalities in a single host. Integrating virtualization while also meeting the real-time and isolation requirements is non-trivial, and poses significant challenges especially in terms of certification. In recent years, researchers proposed hardware-assisted solutions to face issues coming from virtualization, and recently the use of Operating System (OS) virtualization as a more lightweight approach. Industries are hampered in leveraging this latter type of virtualization despite the clear benefits it introduces, such as reduced overhead, higher scalability, and effortless certification since there is still lack of approaches to address drawbacks. In this position paper, we propose the usage of Intel's CPU security extension, namely SGX, to enable the adoption of enclaves based on unikernel, a flavor of OS-level virtualization, in the context of real-time systems. We present the advantages of leveraging both the SGX isolation and the unikernel features in order to meet the requirements of safety-critical real-time systems and ease the certification process.