## CryptoDB

### Paper: Measure-Rewind-Measure: Tighter Quantum Random Oracle Model Proofs for One-Way to Hiding and CCA Security

Authors: Veronika Kuchta , Monash University Amin Sakzad , Monash University Damien Stehlé , Univ. Lyon, EnsL, UCBL, CNRS, Inria, LIP, Institut Universitaire de France Ron Steinfeld , Monash University Shi-Feng Sun , Monash University, Data61, CSIRO DOI: 10.1007/978-3-030-45727-3_24 (login may be required) Search ePrint Search Google EUROCRYPT 2020 We introduce a new technique called Measure-Rewind-Measure' (MRM) to achieve tighter security proofs in the quantum random oracle model (QROM). We first apply our MRM technique to derive a new security proof for a variant of the double-sided' quantum One-Way to Hiding Lemma (O2H) of Bindel et al. [TCC 2019] which, for the first time, avoids the square-root advantage loss in the security proof. In particular, it bypasses a previous impossibility result' of Jiang, Zhang and Ma [IACR eprint 2019]. We then apply our new O2H Lemma to give a new tighter security proof for the Fujisaki-Okamoto transform for constructing a strong (INDCCA) Key Encapsulation Mechanism (KEM) from a weak (INDCPA) public-key encryption scheme satisfying a mild injectivity assumption.
##### BibTeX
@inproceedings{eurocrypt-2020-30231,
title={Measure-Rewind-Measure: Tighter Quantum Random Oracle Model Proofs for One-Way to Hiding and CCA Security},
booktitle={39th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Zagreb, Croatia, May 10–14, 2020, Proceedings},
series={Lecture Notes in Computer Science},
publisher={Springer},
keywords={QROM;security proof;public-key encryption.},
volume={12105},
doi={10.1007/978-3-030-45727-3_24},
author={Veronika Kuchta and Amin Sakzad and Damien Stehlé and Ron Steinfeld and Shi-Feng Sun},
year=2020
}
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