Alexander Russell
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View article: Taming Iterative Grinding Attacks on Blockchain Beacons
Taming Iterative Grinding Attacks on Blockchain Beacons Open
View article: Crooked indifferentiability of the Feistel Construction
Crooked indifferentiability of the Feistel Construction Open
The Feistel construction is a fundamental technique for building pseudorandom permutations and block ciphers. This paper shows that a simple adaptation of the construction is resistant, even to algorithm substitution attacks -- that is, ad…
View article: Correcting Subverted Random Oracles
Correcting Subverted Random Oracles Open
The random oracle methodology has proven to be a powerful tool for designing and reasoning about cryptographic schemes. In this paper, we focus on the basic problem of correcting faulty or adversarially corrupted random oracles, so that th…
View article: The Decisive Power of Indecision: Low-Variance Risk-Limiting Audits and Election Contestation via Marginal Mark Recording
The Decisive Power of Indecision: Low-Variance Risk-Limiting Audits and Election Contestation via Marginal Mark Recording Open
Risk-limiting audits (RLAs) are techniques for verifying the outcomes of large elections. While they provide rigorous guarantees of correctness, widespread adoption has been impeded by both efficiency concerns and the fact they offer stati…
View article: Deconvolution of Solar Cell Cathodoluminescence Using Fourier Interpolation and Second-derivative Peak Localization
Deconvolution of Solar Cell Cathodoluminescence Using Fourier Interpolation and Second-derivative Peak Localization Open
View article: Fait Accompli Committee Selection: Improving the Size-Security Tradeoff of Stake-Based Committees
Fait Accompli Committee Selection: Improving the Size-Security Tradeoff of Stake-Based Committees Open
We study the problem of committee selection in the context of proof-of-stake consensus mechanisms or distributed ledgers. These settings determine a family of participating parties---each of which has been assigned a non-negative ''stake''…
View article: Stimulus-Induced Relief of Intentionally Incorporated Frustration Drives Refolding of a Water-Soluble Biomimetic Foldamer
Stimulus-Induced Relief of Intentionally Incorporated Frustration Drives Refolding of a Water-Soluble Biomimetic Foldamer Open
Frustrated, or nonoptimal, interactions have been proposed to be essential to a protein’s ability to display responsive behav-ior, such as allostery, conformational signaling, and signal transduction. However, the intentional incorporation…
View article: Blockwise Key Distillation in Satellite-based Quantum Key Distribution
Blockwise Key Distillation in Satellite-based Quantum Key Distribution Open
Free-space satellite communication has significantly lower photon loss than terrestrial communication via optical fibers. Satellite-based quantum key distribution (QKD) leverages this advantage and provides a promising direction in achievi…
View article: Practical Settlement Bounds for Proof-of-Work Blockchains
Practical Settlement Bounds for Proof-of-Work Blockchains Open
Nakamoto proof-of-work ledger consensus currently underlies the majority of deployed cryptocurrencies and smart-contract blockchains. While a long and fruitful line of work has succeeded to identify its exact security region---that is, the…
View article: The Generals' Scuttlebutt
The Generals' Scuttlebutt Open
One of the most successful applications of peer-to-peer communication networks is in the context of blockchain protocols, which-in Satoshi Nakamoto's own words-rely on the "nature of information being easy to spread and hard to stifle." Si…
View article: Domestic violence and abuse in local child safeguarding policy: How is the problem represented?
Domestic violence and abuse in local child safeguarding policy: How is the problem represented? Open
Within the United Kingdom, domestic violence and abuse (DVA) is the most commonly identified factor within child in need assessments, with rates increasing in recent years in addition to 'lockdown'-related spikes. This article examines the…
View article: Genomic Characterization of the Cluster CZ4 Gordonia terrae Phage Oregano
Genomic Characterization of the Cluster CZ4 Gordonia terrae Phage Oregano Open
Oregano is a novel cluster CZ4 bacteriophage isolated from the soil using the bacterial host Gordonia terrae . The Oregano genome is 47,575 bp long and encodes two tyrosine integrases and a toxin/antitoxin system. It shares an immunity rep…
View article: Adaptive Risk-Limiting Ballot Comparison Audits
Adaptive Risk-Limiting Ballot Comparison Audits Open
Risk-limiting audits (RLAs) are rigorous statistical procedures meant to detect invalid election results. RLAs examine paper ballots cast during the election to statistically assess the possibility of a disagreement between the winner dete…
View article: Code Offset in the Exponent
Code Offset in the Exponent Open
Fuzzy extractors derive stable keys from noisy sources. They are a fundamental tool for key derivation from biometric sources. This work introduces a new construction, code offset in the exponent. This construction is the first reusable fu…
View article: Consistency of Proof-of-Stake Blockchains with Concurrent Honest Slot Leaders
Consistency of Proof-of-Stake Blockchains with Concurrent Honest Slot Leaders Open
We improve the fundamental security threshold of eventual consensus Proof-of-Stake (PoS) blockchain protocols under the longest-chain rule by showing, for the first time, the positive effect of rounds with concurrent honest leaders. Curren…
View article: Automatic depression prediction using Internet traffic characteristics on smartphones
Automatic depression prediction using Internet traffic characteristics on smartphones Open
View article: Consistency of Proof-of-Stake Blockchains with Concurrent Honest Slot\n Leaders
Consistency of Proof-of-Stake Blockchains with Concurrent Honest Slot\n Leaders Open
We improve the fundamental security threshold of eventual consensus\nProof-of-Stake (PoS) blockchain protocols under the longest-chain rule by\nshowing, for the first time, the positive effect of rounds with concurrent\nhonest leaders.\n C…
View article: Grant Report on SCH: Personalized Depression Treatment Supported by Mobile Sensor Analytics
Grant Report on SCH: Personalized Depression Treatment Supported by Mobile Sensor Analytics Open
We report on the newly started project "SCH: Personalized Depression Treatment Supported by Mobile Sensor Analytics". The current best practice guidelines for treating depression call for close monitoring of patients, and periodically adju…
View article: Quantum-Access-Secure Message Authentication via Blind-Unforgeability
Quantum-Access-Secure Message Authentication via Blind-Unforgeability Open
View article: Efficient Simulation of Random States and Random Unitaries
Efficient Simulation of Random States and Random Unitaries Open
View article: Linear Consistency for Proof-of-Stake Blockchains
Linear Consistency for Proof-of-Stake Blockchains Open
The blockchain data structure maintained via the longest-chain rule---popularized by Bitcoin---is a powerful algorithmic tool for consensus algorithms. Such algorithms achieve consistency for blocks in the chain as a function of their dept…
View article: Small-Support Uncertainty Principles on $\mathbb{Z}/p$ over Finite Fields
Small-Support Uncertainty Principles on $\mathbb{Z}/p$ over Finite Fields Open
We establish an uncertainty principle for functions $f: \mathbb{Z}/p \rightarrow \mathbb{F}_q$ with constant support (where $p \mid q-1$). In particular, we show that for any constant $S > 0$, functions $f: \mathbb{Z}/p \rightarrow \mathbb…
View article: Large-scale Automatic Depression Screening Using Meta-data from WiFi Infrastructure
Large-scale Automatic Depression Screening Using Meta-data from WiFi Infrastructure Open
Depression is a serious public health problem. Current diagnosis techniques rely on physician-administered or patient self-administered interview tools, which are burdensome and suffer from recall bias. Recent studies have proposed new app…
View article: Ouroboros Genesis
Ouroboros Genesis Open
We present a novel Proof-of-Stake (PoS) protocol, Ouroboros Genesis, that enables parties to safely join (or rejoin) the protocol execution using only the genesis block information. Prior to our work, PoS protocols either required parties …
View article: Fusing Location Data for Depression Prediction
Fusing Location Data for Depression Prediction Open
Recent studies have demonstrated that geographic location features collected using smartphones can be a powerful predictor for depression. While location information can be conveniently gathered by GPS, typical datasets suffer from signifi…
View article: One-Dimensional Packing: Maximality and Rationality
One-Dimensional Packing: Maximality and Rationality Open
Every set of natural numbers determines a generating function convergent for $q \in (-1,1)$ whose behavior as $q \rightarrow 1^-$ determines a germ. These germs admit a natural partial ordering that can be used to compare sizes of sets of …
View article: Germ order for one-dimensional packings
Germ order for one-dimensional packings Open
Every set of natural numbers determines a generating function convergent for $q \in (-1,1)$ whose behavior as $q \rightarrow 1^-$ determines a germ. These germs admit a natural partial ordering that can be used to compare sets of natural n…
View article: How to Realize a Graph on Random Points
How to Realize a Graph on Random Points Open
We are given an integer $d$, a graph $G=(V,E)$, and a uniformly random embedding $f : V \rightarrow \{0,1\}^d$ of the vertices. We are interested in the probability that $G$ can be "realized" by a scaled Euclidean norm on $\mathbb{R}^d$, i…
View article: Joint Modeling of Heterogeneous Sensing Data for Depression Assessment via Multi-task Learning
Joint Modeling of Heterogeneous Sensing Data for Depression Assessment via Multi-task Learning Open
Depression is a common mood disorder that causes severe medical problems and interferes negatively with daily life. Identifying human behavior patterns that are predictive or indicative of depressive disorder is important. Clinical diagnos…
View article: Quantum-secure message authentication via blind-unforgeability
Quantum-secure message authentication via blind-unforgeability Open
Formulating and designing authentication of classical messages in the presence of adversaries with quantum query access has been a longstanding challenge, as the familiar classical notions of unforgeability do not directly translate into m…