0000000000659688

AUTHOR

Dominique Unruh

showing 2 related works from this author

Quantum Security Proofs Using Semi-classical Oracles

2019

We present an improved version of the one-way to hiding (O2H) Theorem by Unruh, J ACM 2015. Our new O2H Theorem gives higher flexibility (arbitrary joint distributions of oracles and inputs, multiple reprogrammed points) as well as tighter bounds (removing square-root factors, taking parallelism into account). The improved O2H Theorem makes use of a new variant of quantum oracles, semi-classical oracles, where queries are partially measured. The new O2H Theorem allows us to get better security bounds in several public-key encryption schemes.

Provable securityFlexibility (engineering)Post-quantum cryptographyTheoretical computer scienceComputer sciencebusiness.industry0102 computer and information sciences02 engineering and technologyMathematical proofEncryption01 natural sciencesPublic-key cryptographyUnruh effect010201 computation theory & mathematics0202 electrical engineering electronic engineering information engineeringParallelism (grammar)020201 artificial intelligence & image processingbusiness
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Quantum Attacks on Classical Proof Systems - The Hardness of Quantum Rewinding

2014

Quantum zero-knowledge proofs and quantum proofs of knowledge are inherently difficult to analyze because their security analysis uses rewinding. Certain cases of quantum rewinding are handled by the results by Watrous (SIAM J Comput, 2009) and Unruh (Eurocrypt 2012), yet in general the problem remains elusive. We show that this is not only due to a lack of proof techniques: relative to an oracle, we show that classically secure proofs and proofs of knowledge are insecure in the quantum setting. More specifically, sigma-protocols, the Fiat-Shamir construction, and Fischlin's proof system are quantum insecure under assumptions that are sufficient for classical security. Additionally, we show…

FOS: Computer and information sciencesQuantum PhysicsQuantum networkComputer Science - Cryptography and SecurityTheoretical computer scienceFOS: Physical sciencesQuantum capacityQuantum cryptographyQuantum error correctionQuantum algorithmQuantum informationQuantum Physics (quant-ph)Cryptography and Security (cs.CR)Quantum computerQuantum complexity theoryMathematicsComputer Science::Cryptography and Security
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