Quantum Lattice Sieving

Lattices are very important objects in the effort to construct cryptographic primitives that are secure against quantum attacks. A central problem in the study of lattices is that of finding the shortest non-zero vector in the lattice. Asymptotically, sieving is the best known technique for solving the shortest vector problem, however, sieving requires memory exponential in the dimension of the lattice. As a consequence, enumeration algorithms are often used in place of sieving due to their linear memory complexity, despite their super-exponential runtime. In this work, we present a heuristic quantum sieving algorithm that has memory complexity polynomial in the size of the length of the sampled vectors at the initial step of the sieve. In other words, unlike most sieving algorithms, the memory complexity of our algorithm does not depend on the number of sampled vectors at the initial step of the sieve.Comment: A reviewer pointed out an error in the amplitude amplification step in the analysis of Theorem 6. While we believe this error can be resolved, we are not sure how to do it at the moment and are taking down this submissio

Fully Device-Independent Quantum Key Distribution Using Synchronous Correlations

We derive a device-independent quantum key distribution protocol based on synchronous correlations and their Bell inequalities. This protocol offers several advantages over other device-independent schemes including symmetry between the two users and no need for pre-shared randomness. We close a "synchronicity" loophole by showing that an almost synchronous correlation inherits the self-testing property of the associated synchronous correlation. We also pose a new security assumption that closes the "locality" (or "causality") loophole: an unbounded adversary with even a small uncertainty about the users\u27 choice of measurement bases cannot produce any almost synchronous correlation that approximately maximally violates a synchronous Bell inequality

Nelson Oppen combination as a rewrite theory

Solving Satisfiability Modulo Theories (SMT) problems in a key piece in automating tedious mathematical proofs. It involves deciding satisfiability of formulas of a decidable theory, which can often be reduced to solving systems of equalities and disequalities, in a variety of theories such as linear and non-linear real and integer arithmetic, arrays, uninterpreted and Boolean algebra. While solvers exist for many such theories or their subsets, it is common for interesting SMT problems to span multiple theories. SMT solvers typically use refinements of the Nelson-Oppen combination method, an algorithm for producing a solver for the quantifier free fragment of the combination of a number of such theories via cooperation between solvers of those theories, for this case. Here, we present the Nelson-Oppen algorithm adapted for an order-sorted setting as a rewriting logic theory. We implement this algorithm in the Maude System and instantiate it with the theories of real and integer matrices to demonstrate its use in automated theorem proving, and with hereditarily finite sets with reals to show its use with non-convex theories. This is done using both SMT solvers written in Maude itself via reflection (Variant-based satisfiability) and using external solvers (CVC4 and Yices). This work can be considered a first step towards building a rich ecosystem of cooperating SMT solvers in Maude, that modeling and automated theorem proving tools typically written using the Maude System can leverage

Technical Report: Decidable Fragments of Matching Logic

Matching logic is a unifying logic aimed at defining programming language semantics, and reasoning about various program and language properties. It is a general logic designed with minimalism in mind. With only eight syntactic constructs, matching logic can define many important logical frameworks and languages as its theories. Yet, to our knowledge, no research has been conducted into the decidabiltiy of matching logic. In this paper, we begin such an initiative with respect to decidable fragments of matching logic and identify the first non-trivial decidable fragment for the empty theory. Our decision procedure extends a tableau system for modal $\mu$-calculus. We also give an implementation of the proposed decision procedure and show that with modifications, it can be extended to support theories with certain axioms.Ope

KEVM: A Complete Semantics of the Ethereum Virtual Machine

A developing field of interest for the distributed systems and applied cryptography community is that of smart contracts: self-executing financial instruments that synchronize their state, often through a blockchain. One such smart contract system that has seen widespread practical adoption is Ethereum, which has grown to secure approximately 30 billion USD of currency value and in excess of 300,000 daily transactions. Unfortunately, the rise of these technologies has been marred by a repeated series of security vulnerabilities and high pro file contract failures. To address these failures, the Ethereum community has turned to formal verification and program analysis which show great promise due to the computational simplicity and bounded-time execution inherent to smart contracts. Despite this, no fully formal, rigorous, comprehensive, and executable semantics of the EVM (Ethereum Virtual Machine) currently exists, leaving a lack of rigor on which to base such tools. In this work, we present KEVM, the first fully executable formal semantics of the EVM, the bytecode language in which smart contracts are executed. We create this semantics in a framework for executable semantics, the K framework. We show that our semantics not only passes the official 40,683-test stress test suite for EVM implementations, but also reveals ambiguities and potential sources of error in the existing on-paper formalization of EVM semantics on which our work is based. These properties make KEVM an ideal formal reference implementation against which other implementations can be evaluated. We proceed to argue for a semantics-first formal verification approach for EVM contracts, and demonstrate its practicality by using KEVM to verify practically important properties over the arithmetic operation of an example smart contract and the correct operation of a token transfer function in a second contract. We show that our approach is feasible and not computationally restrictive. We hope that our work serves as the base for the development of a wide range of useful formally derived tools for Ethereum, including model checkers, certified compilers, and program equivalence checkers.Ope

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

P0357 (S1601). - Malignant Melanoma of the Gallbladder Masquerading as Cholangitis and Cholecystitis

Introduction: Metastatic Malignant melanoma is reported in the stomach, intestine and colon. The involvement of the gallbladder and the bile duct are extremely rare.Case Description/Methods: A 61-year-old male presented with abdominal pain, nausea, vomiting, fever, chills, and 10lb weight loss. Physical examination was notable for right upper quadrant abdominal tenderness with a positive Murphy’s sign and minimal jaundice. Lab data showed no leukocytosis and normal hemoglobin. Elevated liver tests with Alk Phos 435U/L, ALT 546U/L, AST 474U/L, and Tbili 3.1mg/dl prompted an abdominal ultrasound which showed intrahepatic and extrahepatic bile duct dilatation (common bile duct (CBD) 11mm). A diffusely abnormal thick-walled gall bladder filled with debris was seen. This was concerning for cholecystitis and cholangitis. He was started on piperacillin/tazobactam. An endoscopic ultrasound (EUS) revealed hyperechoic material suggestive of thick sludge versus tissue within gallbladder lumen extending into the CBD (Figure 1a). Endoscopic retrograde cholangio-pancreatography (ERCP) revealed irregular filling defects within CBD close to cystic duct takeoff (Figure 1b). After sphincterotomy, balloon sweeps evacuated pigmented tissue debris (Figure 1c) which was retrieved and sent for pathology. Unusual EUS/ ERCP findings prompted an MRI which showed high T1 signal within periportal nodes and gallbladder suggesting hemorrhage. Surgical consultation was obtained and patient underwent laparoscopic cholecystectomy, but frozen section indicated malignancy, therefore, an open liver resection and lymphadenectomy was completed.The gross pathology showed a 2.5x1.6x1.5cm mass arising from the gallbladder (Figure 2a) with invasion into the peri muscular connective tissue on the hepatic side but with no direct extension. An immunostain on the tumor and the prior biliary tissue debris showed positive staining for Vimentin, and S100 and a diagnosis of melanoma was confirmed (Figure 2b and 2c). Surgical staging was pT2bN1. Skin and ocular examination did not reveal any lesions.Discussion: Melanoma involving the gastrointestinal tract is usually metastatic from known cutaneous melanoma; however primary melanoma of the GI tract have been reported. Within the GI tract, primary gallbladder melanoma is extremely rare with less than 40 cases reported in the literature. Clinical course is typically aggressive; our patient developed metastatic disease to brain soon after gallbladder resection

P0516 (S1638). - An Unexpected Cause of Colitis in a Cardiac Transplant Patient

Introduction: Mycophenolate induced colitis is an unexpected complication of the immunosuppression medication.Case Description/Methods: A 36 year-old-female with a history of Epstein’s anomaly underwent repeat orthotropic heart transplant in 2020 due to primary graft failure of the first transplant in 2019. Mycophenolate had been changed to Myfortic for abdominal complaints prior to retransplant. She had early mild allograft dysfunction despite unremarkable prospective crossmatch and first surveillance right ventricular biopsy (RVB). She was empirically treated with rituximab, high dose intravenous steroids, serial plasmapheresis, and IVIG.Despite improving cardiac function, she developed acute hypoxic respiratory failure, acute on subacute renal failure, and worsening anemia. Repeat RVB revealed acute antibody and T-cell mediated rejection; the Myfortic dose was increased. Two weeks later the patient developed abdominal pain and loose maroon-colored bloody stool.Lab data showed a white blood cell count of 3.61k/ul and hemoglobin of 9.1g/dl. Elevated liver tests: Alk Phos 143U/L and ALT 111U/L. The CRP was normal however the fecal calprotectin was greater than 1250 ug/g. The SARS-CoV-2 and stool studies including clostridioides difficile, serum CMV IgG yielded negative results. A CT scan showed distension of the colon with an average amount of retained stool and gas. No bowel inflammation was noted.Colonoscopy showed diffuse edematous folds, loss of vascularity, and friable mucosa with dispersed aphthous ulcers and erosions from cecum to the sigmoid colon (Figure 1a, 1b, and 1c). The mucosa was biopsied with concern for inflammatory bowel disease, viral etiology, or undiagnosed inflammatory bowel disease.On histology, the colon mucosa was noted to have interstitial edema, abortive mitosis, eosinophilia, and scattered dilated irregular shaped crypts, most consistent with Mycophenolate related colitis (Figure 2). There was no evidence of viral inclusion bodies.Myfortic was replaced with renal dosing of Azathioprine. There was a dramatic improvement in appetite, nausea, energy, and renal function with no subsequent bloody stools or abdominal pain.Discussion: There are very few reported cases of Mycophenolate induced colitis. Our patient developed bloody stools, acute kidney injury and abdominal pain as was the case in other reports. An elevated fecal calprotectin and the above biopsy findings helped clinch the diagnosis. New-onset colitis can be noted even if the patient was previously on Mycophenolate

BEAVr: Version 1.0

Initial release of BEAVr: Bounded Expansion Algorithm Visualizer. BEAVr is a Python tool offering interactive visualization of the algorithmic pipeline for counting subgraph isomorphisms in graph classes of bounded expansion, as implemented in CONCUSS. BEAVr visually represents the data transformations and information in each stage of the pipeline (p-centered colorings, tree-depth decompositions, dynamic programming with k-patterns, and final counts via inclusion-exclusion). For researchers, BEAVr also enables exploration of new coloring heuristics via detailed visualization of each step of the coloring stage