157 citations · 815 across the 35 of their papers we have counts for
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Security of the Fischlin Transform in Quantum Random Oracle Model
Christian Majenz, Jaya Sharma
The Fischlin transform yields non-interactive zero-knowledge proofs with straight-line extractability in the classical random oracle model. This is done by forcing a prover to gene…
Quantum Oracle Distribution Switching and Applications to Falcon and Ring Signatures
Marvin Beckmann, Christian Majenz
Motivated by digital signature algorithms ranging from Falcon to fully-anonymous ring signatures used in Signal-style key exchange, such as Gandalf, we revisit a fundamental proble…
Post-Quantum Security of Block Cipher Constructions
Gorjan Alagic, Chen Bai, Christian Majenz +1
Block ciphers are versatile cryptographic ingredients that are used in a wide range of applications ranging from secure Internet communications to disk encryption. While post-quant…
Failing gracefully: Decryption failures and the Fujisaki-Okamoto transform
Kathrin Hövelmanns, Andreas Hülsing, Christian Majenz
In known security reductions for the Fujisaki-Okamoto transformation, decryption failures are handled via a reduction solving the rather unnatural task of finding failing plaintext…
Efficient NIZKs and Signatures from Commit-and-Open Protocols in the QROM
Jelle Don, Serge Fehr, Christian Majenz +1
Commit-and-open Sigma-protocols are a popular class of protocols for constructing non-interactive zero-knowledge arguments and digital-signature schemes via the Fiat-Shamir transfo…
Online-Extractability in the Quantum Random-Oracle Model
Jelle Don, Serge Fehr, Christian Majenz +1
We show the following generic result. Whenever a quantum query algorithm in the quantum random-oracle model outputs a classical value that is promised to be in some tight relat…
The Measure-and-Reprogram Technique 2.0: Multi-Round Fiat-Shamir and More
Jelle Don, Serge Fehr, Christian Majenz
We revisit recent works by Don, Fehr, Majenz and Schaffner and by Liu and Zhandry on the security of the Fiat-Shamir transformation of -protocols in the quantum random oracle mo…
Security of the Fiat-Shamir Transformation in the Quantum Random-Oracle Model
Jelle Don, Serge Fehr, Christian Majenz +1
The famous Fiat-Shamir transformation turns any public-coin three-round interactive proof, i.e., any so-called sigma-protocol, into a non-interactive proof in the random-oracle mod…