Since 2016, Apple has claimed that device analytics collected to improve user experience are protected by differential privacy (DP). Apple's DifferentialPrivacy framework is deployed across its operating systems and handles sensitive signals such as Safari domains, keyboard events, photo attributes, and health-related reports. Because Apple has not open-sourced its privatization algorithms, these privacy claims have been difficult to verify independently. We present a client-side audit of Apple's DP framework on macOS Sonoma 14.2 and Sequoia 15.6. We reverse engineer the shipped binaries, recover Objective-C interfaces, build runtime harnesses that execute Apple's deployed mechanisms, and test whether their outputs match the advertised privacy guarantees. Our audit covers nearly all active deployed mechanisms, including Count Median Sketch, Hadamard-CMS, randomized-response mechanisms, and Prio-style secure aggregation. We find multiple implementation bugs and misconfigurations. Every audited mechanism that relies on floating-point noise fails to meet its advertised DP or zero-knowledge proof guarantee, due to insecure samplers with known floating-point vulnerabilities. We also find secure-aggregation configurations with local DP disabled, exposing pre-aggregation records to any party with access to those logs. Overall, we find DP violations in 5 of 9 audited mechanisms, affecting 87% of data collection in macOS Sonoma and 68% in Sequoia. We also identify public leaked iPhone logs that can be decoded to recover private information, including Safari domains and keyboard emoji signals.

Data collaboration with cloud technologies is becoming more popular for personal use as well as business applications. Due to the increasing data protection regulations worldwide, different cryptographic techniques have been designed to enable secure data sharing for a user or a group of users. Although, these techniques have seen enterprise adoption, they fail to offer data visibility as data remains encrypted throughout the data sharing routine. This is why these techniques fail to offer a key features to data users, e.g., joining different datasets together and sharing it with all the users involved. This paper presents a blockchain based architecture for secure data collaboration in cloud using differentially private synthetic data and trusted execution environment (TEE). The proposed solution protects data confidentiality and integrity with TEEs, supports public-key infrastructure (PKI) with blockchain, and prevents privacy leakages with synthetic data. The results show that our synthetic data performs as good as real data and demonstrates how different users can securely aggregate their datasets and openly share among themselves.

One of the most important and critical requirements for the Internet of Vehicles (IoV) is security under strict latency. Typically, authentication protocols for vehicular ad hoc networks need to authenticate themselves frequently. This results in reduced application traffic and increased overhead. Moreover, the mobile nature of vehicles makes them a prime target for physical, side channel, and cloning attacks. To address these issues, this article presents an efficient protocol for authentication in the IoV. The proposed protocol uses physical unclonable functions to provide the desired security characteristics. To reduce the overhead of authentication and improve the throughput of application layer packets, the proposed protocol uses a three-layered infrastructure architecture for IoVs, i.e., roadside units (RSUs), RSU gateways, and trusted authority. A vehicle needs to authenticate only once when it enters the area of an RSU gateway which may engulf multiple RSUs. A performance analysis of the protocol shows that the proposed strategy significantly reduces the number of authentication packets and MAC/PHY overhead while the security analysis demonstrates its robustness against various types of attacks.

Industry 4.0 represents the fourth industrial revolution that will leverage the industrial Internet of Things (IIoT) to introduce adaptive and autonomous systems that can self-heal and self-learn. IIoT aims to promote businesses and industries by realizing intelligent industrialization. However, the constantly surging data volumes that are generated by IIoT environments present security issues like data integrity and system scalability. Blockchain is a promising candidate to address these problems, which offers distributed system design principles. Though blockchain-based IIoT frameworks may have the potential to support the demands and services of next-generation industrial systems, their integration is still constrained by significant challenges in scalability and security. Therefore, blockchain in its original structure with traditional proof-of-work consensus is not suitable for IIoT. To address this, we propose a blockchain architecture that uses a dynamic proof-of-work consensus with a block checkpoint mechanism. The dynamic consensus functions with different mining difficulty levels allow the architecture to efficiently scale with increase in communication traffic of IIoT devices, whereas the checkpoint defines an alternative mechanism to generate the next block hash in the blockchain. To study the scalability and feasibility of the architecture, thorough performance and security analyses are presented, which attest that it can scale and offer enhanced security fidelity with a minimal increase in block mining time.

The constantly growing number of Internet of Things (IoT) devices and their resource-constrained nature makes them particularly vulnerable and increasingly attractive for exploitation by cyber criminals. Current estimates commonly reach the tens of billions for the number of connected 'things'. The heterogeneous capabilities of these devices serve as a motivation for resource sharing among them. However, for effective resource sharing, it is essential that trust be retained in the multitude of pervasive and diverse IoT devices. Remote attestation is a well-known technique used to build such trust. Thus, this paper proposes a blockchain based remote attestation protocol to establish trust between IoT devices. The blockchain offers a secure framework for device registration while the attestation is based on Physical Unclonable Functions (PUF). This combination of technologies results in a tamper resistant scheme with protection against physical and proxy attacks.

Recent developments in IoT have facilitated advancements in the Internet of Vehicles (IoV) with autonomous vehicles and roadside infrastructure as its key components. IoV aims to provide new innovative services for different modes of transport with adaptive traffic management and enables vehicles to broadcast messages to improve traffic safety and efficiency. However, due to nontrusted environments, it is difficult for vehicles to evaluate the credibility of the messages that they receive. Therefore, trust establishment in IoV is a key security concern that is constantly limited by scalability challenges. This article proposes a blockchain-based protocol for IoV using smart contracts, physical unclonable functions (PUFs), certificates, and a dynamic Proof-of-Work (dPoW) consensus algorithm. The blockchain, in conjunction with contracts, provides a secure framework for registering trusted vehicles and blocking malicious ones. PUFs are used to assign a unique identity to each vehicle via which trust is established. Certificates are issued by roadside units that preserve the privacy of vehicles, whereas the dPoW consensus allows the protocol to scale according to the incoming traffic generated by the vehicles. To demonstrate the feasibility and scalability of the proposed protocol, security and performance analyses are presented. A case study is also discussed along with a comparative analysis, which confirms that our protocol can provide superior decentralized trust management for IoV.

The development of Internet of Things (IoT) has paved way for the Internet of Vehicles (IoV) and intelligent transportation systems (ITS). Vehicular ad-hoc networks (VANETs) are indispensable for ITS with intelligent vehicles (IV) as their key players. To ensure proper and reliable VANET operation, IVs need secure inter- and intra-network communication with trust and reliability of data (provenance). This paper aims to provide trust management in VANETs by proposing a trustless system model using blockchain and a certificate authority (CA) for registering IVs as well as revoking their registration if need be. Furthermore, to preserve data reliability, this paper uses physical unclonable functions (PUFs). Implementation of DrivMan shows that it is able to establish distributed trust management and enables secure data sharing while preserving the privacy of IVs.

This paper presents comparative evaluation and explores the different technologies suitable for the implementation of the Medium Voltage Direct Current (MVDC) electrical supplies for the marine on-board electrical distribution network. To realize the MVDC supply in the range from 5 kV to 25 kV, various technological choices are available during the design process and have a direct influence on the overall system performances. In this work we discuss different prime movers, choice of electrical generators and type of rectifiers. Different configurations are characterized with different metrics, in terms of commercial availability, quality of supply, efficiency, dynamic performance and volume. Multi-phase multi-pulse supply configurations are identified to provide high quality dc supply and recommended for marine MVDC distribution.

Marine high-power on-board electrical systems are predominantly utilizing three-phase medium voltage alternating current (MVAC) distribution. Depending on the size and purpose of the ship, on-board electrical systems provide supply to loads in excess of 60MW. Increasingly, medium voltage direct current (MVDC) distribution systems are being considered as an alternative. An increase in the fuel efficiency of the prime movers, the removal of bulky low frequency transformer and the easier integration of different storage technologies are especially attractive. This paper discusses the opportunities but also the technical difficulties associated with the transition from an MVAC to an MVDC system, using an existing LNG tanker MVAC on-board distribution system, as example.