In today's digital landscape, the ubiquity of mobile devices underscores the urgent need for stringent security protocols in both data transmission and storage. Plausibly deniable encryption (PDE) stands out as a pivotal solution, particularly in jurisdictions marked by rigorous regulations or increased vulnerabilities of personal data. However, the existing PDE systems for mobile platforms have evident limitations. These include vulnerabilities to multi-snapshot attacks over RAM and flash memory, an undue dependence on non-secure operating systems, traceable PDE entry point, and a conspicuous PDE application prone to reverse engineering.

Random numbers play a crucial role in decen-tralized applications (dApps) like decentralized finance (DeFi) and non-fungible tokens (NFTs). However, their generation faces challenges due to blolckchain's deterministic and decentralized nature, risking smart contract security and ecosystem stability. Prior solutions, including Oracles, employing commit-execute schemes, suffer from higher transaction fees, extended processing times, and increased on-chain storage, compromising efficiency. This paper proposes a novel random number provider (RNP) protocol for smart contracts, eliminating dependencies on traditional commit-execute approaches. Furthermore, we systematically identify potential random number-related attacks on smart contracts, particularly Post-reveal Undo Attacks (PUAs), where attackers may reverse contract operations when randomness is unfavorable, and discuss the security requirements. Our protocol addresses these attacks by (1) incorporating distributed random beacons (D RBs) with consensus processes, bridging the semantic gap between DRB and consensus, and (2) thoroughly analyzing and classifying four types of PUA and offering robust mitigations, alongside presenting a security proof. Our experiments show the protocol significantly enhances response times and security for random number queries in smart contracts, slashing request fees by at least 89 % and reducing on-chain data by 76.4% versus current methods. This work advances the integration of DRB protocols and consensus mechanisms, securing and optimizing random number applications in dApps, thus fostering the creation of more dependable, robust systems.

State channel network is the most popular layer-2 solution to the issues of scalability, high transaction fees, and low transaction throughput of public Blockchain networks. However, the existing works have limitations that curb the wide adoption of the technology, such as the expensive creation and closure of channels, strict synchronization between the main chain and off-chain channels, frozen deposits, and inability to execute multi-party smart contracts. In this work, we present Speedster, an account-based state-channel system that aims to address the above issues. To this end, Speedster leverages the latest development of secure hardware to create dispute-free certified channels that can be operated efficiently off the Blockchain. Speedster is peer-to-peer decentralized and provides better privacy protection than prior channel projects. It supports fast native multi-party contract execution, which is previously unavailable in TEE-enabled channel networks. Compared to the Lightning Network, Speedster improves the throughput by about 10,000X and generates 97%$ less on-chain data with a comparable network scale.

Live kernel patching is an increasingly common trend in operating system distributions, enabling dynamic updates to include new features or to fix vulnerabilities without having to reboot the system. Patching the kernel at runtime lowers downtime and reduces the loss of useful state from running applications. However, existing kernel live patching techniques (1) rely on specific support from the target operating system, and (2) admit patch failures resulting from kernel faults. We present KSHOT, a kernel live patching mechanism based on x86 SMM and Intel SGX that focuses on patching Linux kernel security vulnerabilities. Our patching processes are protected by hardware-assisted Trusted Execution Environments. We demonstrate that our technique can successfully patch vulnerable kernel functions at the binary-level without support from the underlying OS and regardless of whether the kernel patching mechanism is compromised. We demonstrate the applicability of KSHOT by successfully patching 30 critical indicative kernel vulnerabilities.