169 research outputs found
AntFuzzer: A Grey-Box Fuzzing Framework for EOSIO Smart Contracts
In the past few years, several attacks against the vulnerabilities of EOSIO
smart contracts have caused severe financial losses to this prevalent
blockchain platform. As a lightweight test-generation approach, grey-box
fuzzing can open up the possibility of improving the security of EOSIO smart
contracts. However, developing a practical grey-box fuzzer for EOSIO smart
contracts from scratch is time-consuming and requires a deep understanding of
EOSIO internals. In this work, we proposed AntFuzzer, the first highly
extensible grey-box fuzzing framework for EOSIO smart contracts. AntFuzzer
implements a novel approach that interfaces AFL to conduct AFL-style grey-box
fuzzing on EOSIO smart contracts. Compared to black-box fuzzing tools,
AntFuzzer can effectively trigger those hard-to-cover branches. It achieved an
improvement in code coverage on 37.5% of smart contracts in our benchmark
dataset. AntFuzzer provides unified interfaces for users to easily develop new
detection plugins for continually emerging vulnerabilities. We have implemented
6 detection plugins on AntFuzzer to detect major vulnerabilities of EOSIO smart
contracts. In our large-scale fuzzing experiments on 4,616 real-world smart
contracts, AntFuzzer successfully detected 741 vulnerabilities. The results
demonstrate the effectiveness and efficiency of AntFuzzer and our detection p
Antiferromagnetic fluctuations and a dominant -wave pairing symmetry in nickelate-based superconductors
Motivated by recent experimental studies on superconductivity found in
nickelate-based materials, we study the temperature dependence of the spin
correlation and the superconducting pairing interaction within an effective
two-band Hubbard model by the quantum Monte Carlo method. Based on parameters
extracted from first-principles calculations, our intensive numerical results
reveal that the pairing with a -wave symmetry firmly dominates over
other pairings at low temperature, which is mainly determined by the Ni 3
orbital. It is also found that the effective pairing interaction is enhanced as
the on-site interaction increases, demonstrating that the superconductivity is
driven by strong electron-electron correlation. Even though the
antiferromagnetic correlation could be enhanced by electronic interaction,
there is no evidence for long-range antiferromagnetic order exhibited in
nickelate-based superconductors. Moreover, our results offer possible evidence
that the pure electron correlation may not account for the charge density wave
state observed in nickelates.Comment: Published versio
Estimation of surface shortwave radiation components under all sky conditions: Modeling and sensitivity analysis
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