Secure boot ensures that only verified code is executed at boot time. It typically relies on asymmetric cryptography, which may pose boot time challenges for time-critical devices. We, therefore, propose an efficient secure boot (ESB) mechanism that extends the asymmetric cryptography-based approach with symmetric cryptography to reduce boot time. To demonstrate the practicality, an extended Device Identifier Composition Engine (DICE) architecture is leveraged as a use case. The evaluation results on an ARM-based MCU show that the proposed mechanism reduces boot time for regular boots while introducing a slightly higher overhead only during the initial boot phase.

Gaussian integers are a subset of complex numbers that have integer numbers in both their real and imaginary parts. Similar to ordinary integer numbers, they can be equipped with modulo operations, which creates Gaussian integer rings and fields. Depending on the chosen modulus, these structures can be isomorphic to corresponding algebraic structures over integer numbers. However, computing modulo reduction for Gaussian integers can be computationally expensive, especially when the modulus itself is a Gaussian integer.In this work, we present a novel and efficient reduction algorithm for Gaussian integer moduli of arbitrary form based on the ideas of Barrett reduction for integer numbers. We show that the computational complexity of our proposed reduction algorithm is equivalent to previously known Montgomery reduction over Gaussian integers. However, unlike Montgomery’s approach, our algorithm does not require domain transformations and can be more advantageous in various circumstances.

The project VE-FIDES will contribute with a solution based on an innovative multi-level fingerprinting approach to secure electronics supply chains against the threats of malicious modification, piracy, and counterfeiting. Hardware-fingerprints are derived from minuscule, unavoidable process variations using the technology of Physical Unclonable Functions (PUFs). The derived fingerprints are processed to a system fingerprint enabling unique identification, not only of single components but also on PCB level. With the proposed concept, we show how the system fingerprint can enhance the trustworthiness of the overall system. For this purpose, the complete system including tiny sensors, a Secure Element and its interface to the application is considered in VE-FIDES. New insights into methodologies to derive component and system fingerprints are gained. These techniques for the verification of system integrity are complemented by methods for preventing reverse engineering. Two application scenarios are in the focus of VE-FIDES: Industrial control systems and an automotive use case are considered, giving insights to a wide spectrum of requirements for products built from components provided by international supply chains.

Gaussian integers are a subset of the complex numbers with integers as real and imaginary parts. When Gaussian integers are equipped with modulo operations, they form Gaussian integer rings or fields, depending on the specific choice of the modulus. Arithmetic on Gaussian integers can offer advantages in terms of operand size and improved parallelism, due to independent calculation of the real and imaginary parts. However, although Gaussian integer modulo reduction is the fundamental operation to enable computations in finite Gaussian integer rings and fields, efficient algorithms for Gaussian integer modulo reduction have not been widely investigated so far. In this work, we fill this gap and present efficient reduction algorithms for Gaussian integer moduli of special forms. Indeed, we demonstrate that there exist different classes of Gaussian integer moduli allowing for very fast reductions. Finally, we show that the computational complexity of the proposed algorithm is significantly reduced compared with generic Gaussian integer reduction methods known to date, e.g., Montgomery-based reduction for Gaussian integers.