Ruhr-Universität Bochum (RUB): Open Journal Systems
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Another Evidence to not Employ Customized Masked Hardware: Identifying and Fixing Flaws in SCARV
No full textAs a well-studied countermeasure against side-channel analysis attacks, there is a general interest in applying masking to different cryptographic functions executed on different platforms. On the one hand, despite their high performance, masked hardware implementations are dedicated to specific algorithms, making them inflexible. On the other hand, applying masking on software involves serious challenges including significant overhead in terms of efficiency and difficulties to maintain theoretical security guarantees in practice. As a result, a line of research has been devoted to enable masked operations in flexible platforms (i.e., microprocessors) by including some masked modules in their hardware, hence a combination of flexibility and performance. In such scenarios, RISC-V is a natural choice as hardware can be adjusted to the extended instruction set. One such attempt presented at CHES 2021 is known as SCARV, which extends the Instruction Set Architecture (ISA) of a RISC-V core with a rich number of first-order masked operations on both Boolean and arithmetic masked operands. In this work, we conduct a comprehensive analysis of SCARV. Instead of relying on empirical measurements to demonstrate security, we utilize tool-assisted evaluations. Through these evaluations, we identified a couple of design flaws that lead to leakage in the masked implementations hosted by the corresponding processor. These flaws are primarily due to the lack of composability of cascaded components. While heuristic and ad-hoc design principles can result in secure, small, and efficient designs, they lack formal security proofs, which may lead to security flaws, like those we report here. Consequently, this work serves as a motivation for using composable masked modules and tool-assisted evaluations when constructing complex circuits
Masking FALCON’s Floating-Point Multiplication in Hardware
No full textFloating-point arithmetic is a cornerstone in a wide array of computational domains, and it recently became a building block for the FALCON post-quantum digital signature algorithm. As a consequence, the side-channel security of these operations became under scrutiny. Recent works unveiled the first side-channel attack specifically targeting floating-point multiplication to steal secret cryptographic keys. Despite these new attacks on floating point arithmetic, there is no secure hardware design for side-channel leakage to date. A concurrent work has applied masking of floating-point multiplication in software [CC24], but their empirical validation still demonstrated significant first-order leakages. This paper presents the first hardware masking scheme for floating-point multiplication to mitigate side-channel attacks. Our technique extends the cryptographic masking principles that split all intermediate computations into multiple, random shares while preserving the output functionality. Our innovation also provides a design-time configurable first-order masked multiplier gadget that carries out integer multiplication, which can support future designs. To that end, we propose new hardware gadgets including Integer Multiplier, Carry Calculator, Secure MUX, Zero Check, and Mantissa Selection, and we prove their security in the PINI model. Moreover, we validate the desired firstorder side-channel security of our implementation on a Sakura-X FPGA board using 10 million measurements. We explore the design space with different architectural choices to trade-off performance for the area. Our implementation results show that masking overhead ranges between 5.42x-43.31x in the area and 2x-440x in throughput
FaultDetective: Explainable to a Fault, from the Design Layout to the Software
No full textHardware faults are a known source of security vulnerabilities. Fault injection in secure embedded systems leads to information leakage and privilege escalation, and countless fault attacks have been demonstrated both in simulation and in practice. However, there is a significant gap between simulated fault attacks and physical fault attacks. Simulations use idealized fault models such as single-bit flips with uniform distribution. These ideal fault models may not hold in practice. On the other hand, practical experiments lack the white-box visibility necessary to determine the true nature of the fault, leading to probabilistic vulnerability assessments and unexplained results. In embedded software, this problem is further exacerbated by the layered abstractions between the hardware (where the fault originates) and the application software (where the fault effect is observed). We present FaultDetective, a method to investigate the root-cause of fault injection from fault detection in software. Our main insight is that fault detection in software is only the end-point of a chain of events that starts with a fault manifestation in hardware and propagates through the micro-architecture and architecture before reaching the software level. To understand the fault effects at the hardware level, we use a scan chain, a low-level hardware test structure. We then use white-box simulation to propagate and observe hardware faults in the embedded software. We efficiently visualize the fault propagation across abstraction levels using a hash-tree representation of the scan chain. We implement this concept in a multi-core MSP430 micro-controller that redundantly executes an application in lock-step. With this setup, we observe the fault effects for several different stressors, including clock glitching and thermal laser stimulation, and explain the root-cause in each case
Der ‚Folkwang-Gedanke‘* von Karl Ernst Osthaus zu Ernst Gosebruch bis heute?! Probleme einer Begriffsgenese und Displayorganisation aus postkolonialer Perspektive
Get PDF„Cultures don’t Converse“ – Das Display im Musée du Quai Branly ‘ou le dialogue des cultures’
Get PDFImagining what you intend
Get PDFIf we are free to imagine what we choose, this is likely because our intentions determine what we are imagining. However, in a recent article, Munro and Strohminger (2021) argue that, in some cases of imagistic imagining, our intentions do not determine what we are imagining. They offer examples where, intuitively, a person intends to imagine one thing but, due to the causal source of the image used, imagine another. This paper acknowledges the challenge posed by these cases while arguing on several grounds that, when present, intentions nevertheless always suffice to determine the object of one’s imaginings. I conclude by explaining how intentions could fix the objects of episodic rememberings in much the same way as they do for imaginings, thereby bolstering the case that remembering is a kind of imagining
Una talaia sobre el music-hall: anàlisi de la crítica teatral del periodista Joan Tomàs a "Mirador"
Get PDFJoan Tomàs (Igualada, 1892 – Mexico City, 1962) is one of the most preeminent Catalan theatre critics and cultural journalists during the 20th century. He was a contributor for a wide range of publications, including El Diluvio, La Publicitat, El Poble Català, El be negre, L’Opinió and Mirador. As a result of the Civil War, he went into exile in France and then in Mexico, where he continued to work as a journalist until his death in 1962. This paper analyses articles on the music-hall subject which Tomàs published between 1929 and 1936 in Mirador.Joan Tomàs (Igualada, 1892 – Mexico City, 1962) is one of the most preeminent Catalan theatre critics and cultural journalists during the 20th century. He was a contributor for a wide range of publications, including El Diluvio, La Publicitat, El Poble Català, El be negre, L’Opinió and Mirador. As a result of the Civil War, he went into exile in France and then in Mexico, where he continued to work as a journalist until his death in 1962. This paper analyses articles on the music-hall subject which Tomàs published between 1929 and 1936 in Mirador.Joan Tomàs (Igualada, 1892 – Mexico City, 1962) is one of the most preeminent Catalan theatre critics and cultural journalists during the 20th century. He was a contributor for a wide range of publications, including El Diluvio, La Publicitat, El Poble Català, El be negre, L’Opinió and Mirador. As a result of the Civil War, he went into exile in France and then in Mexico, where he continued to work as a journalist until his death in 1962. This paper analyses articles on the music-hall subject which Tomàs published between 1929 and 1936 in Mirador
