1,559 research outputs found
A Touch of Evil: High-Assurance Cryptographic Hardware from Untrusted Components
The semiconductor industry is fully globalized and integrated circuits (ICs)
are commonly defined, designed and fabricated in different premises across the
world. This reduces production costs, but also exposes ICs to supply chain
attacks, where insiders introduce malicious circuitry into the final products.
Additionally, despite extensive post-fabrication testing, it is not uncommon
for ICs with subtle fabrication errors to make it into production systems.
While many systems may be able to tolerate a few byzantine components, this is
not the case for cryptographic hardware, storing and computing on confidential
data. For this reason, many error and backdoor detection techniques have been
proposed over the years. So far all attempts have been either quickly
circumvented, or come with unrealistically high manufacturing costs and
complexity.
This paper proposes Myst, a practical high-assurance architecture, that uses
commercial off-the-shelf (COTS) hardware, and provides strong security
guarantees, even in the presence of multiple malicious or faulty components.
The key idea is to combine protective-redundancy with modern threshold
cryptographic techniques to build a system tolerant to hardware trojans and
errors. To evaluate our design, we build a Hardware Security Module that
provides the highest level of assurance possible with COTS components.
Specifically, we employ more than a hundred COTS secure crypto-coprocessors,
verified to FIPS140-2 Level 4 tamper-resistance standards, and use them to
realize high-confidentiality random number generation, key derivation, public
key decryption and signing. Our experiments show a reasonable computational
overhead (less than 1% for both Decryption and Signing) and an exponential
increase in backdoor-tolerance as more ICs are added
Leakage-Resilient Group Signature: Definitions and Constructions
Group signature scheme provides group members a way to sign messages without revealing their identities. Anonymity and traceability are two essential properties in a group signature system. However, these two security properties hold based on the assumption that all the signing keys are perfectly secret and leakage-free. On the another hand, on account of the physical imperfection of cryptosystems in practice, malicious attackers can learn fraction of secret state (including secret keys and intermediate randomness) of the cryptosystem via side-channel attacks, and thus breaking the security of whole system.
To address this issue, Ono et al. introduced a new security model of group signature, which captures randomness exposure attacks. They proved that their proposed construction satisfies the security require-ments of group signature scheme. Nevertheless, their scheme is only provably secure against randomness exposure and supposes the secret keys remains leakage-free. In this work, we focus on the security model of leakage-resilient group signature based on bounded leakage setting and propose three new black-box constructions of leakage-resilient group signature secure under the proposed security models
A Survey of Leakage-Resilient Cryptography
In the past 15 years, cryptography has made considerable progress in expanding the adversarial attack model to cover side-channel attacks, and has built schemes to provably defend against some of them. This survey covers the main models and results in this so-called leakage-resilient cryptography
Critical Behavior in Evolutionary and Population Dynamics
This study is an exploration of phase transition behavior in evolutionary and population dynamics, and techniques for predicting population changes, across the disciplines of physics, biology, and computer science. Under the looming threat of climate change, it is imperative to understand the dynamics of populations under environmental stress and to identify early warning signals of population decline. These issues are explored here in (1) a computational model of evolutionary dynamics, (2) an experimental system of decaying populations under environmental stress, and (3) a machine learning approach to predict population changes based on environmental factors. Through the lens of critical phase transition behavior, the non-equilibrium continuous transition of a neutral agent-based model is shown to exhibit power-law-like behavior for two control parameters in the critical regime. The model does not fall within the directed percolation universality class, despite exhibiting some characteristics of directed percolation. The results also compare a system exhibiting quenched randomness with one that does not. Experimentally, the impact of two stressors, temperature and NaCl stress, are examined in S. cerevisiae. Increased levels of NaCl in growth media result in a smooth transition from a survivable to an uninhabitable environment, whereas increased temperature stress results in a transition with signs of critical behavior. Lastly, population data from the Living Planet Index and weather data from NOAA are used to predict population changes based on weather attributes using classification and regression machine learning models. Results indicate that a machine learning approach is viable, but additional data and environmental factors are needed to improve the predictive models
Group key exchange protocols withstanding ephemeral-key reveals
When a group key exchange protocol is executed, the session key is typically extracted from two types of secrets; long-term keys (for authentication) and freshly generated (often random) values. The leakage of this latter so-called ephemeral keys has been extensively analyzed in the 2-party case, yet very few works are concerned with it in the group setting. We provide a generic {group key exchange} construction that is strongly secure, meaning that the attacker is allowed to learn both long-term and ephemeral keys (but not both from the same participant, as this would trivially disclose the session key). Our design can be seen as a compiler, in the sense that it builds on a 2-party key exchange protocol which is strongly secure and transforms it into a strongly secure group key exchange protocol by adding only one extra round of communication. When applied to an existing 2-party protocol from Bergsma et al., the result is a 2-round group key exchange protocol which is strongly secure in the standard model, thus yielding the first construction with this property
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