References of "Rosie, Razvan 50033778"
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See detailOn the (M)iNTRU assumption in the integer case
Barthel, Jim Jean-Pierre UL; Müller, Volker UL; Rosie, Razvan UL

in Provable and Practical Security, 15th International Conference, ProvSec 2021, Guangzhou, November 5 – November 8, 2021, Proceedings (in press)

In AsiaCrypt 2019, Genise, Gentry, Halevi, Li and Micciancio put forth two novel and intriguing computational hardness hypotheses: The inhomogeneous NTRU (iNTRU) assumption and its matrix version MiNTRU ... [more ▼]

In AsiaCrypt 2019, Genise, Gentry, Halevi, Li and Micciancio put forth two novel and intriguing computational hardness hypotheses: The inhomogeneous NTRU (iNTRU) assumption and its matrix version MiNTRU. In this work, we break the integer case of the iNTRU assumption through elementary lattice reduction, and we describe how the attack might be generalized to polynomial rings and to the low dimensional MiNTRU assumption with small noise. [less ▲]

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See detailNIKE from Affine Determinant Programs
Barthel, Jim Jean-Pierre UL; Rosie, Razvan UL

in Qiong, Huang; Yu, Yu (Eds.) Provable and Practical Security, 15th International Conference, ProvSec 2021, Guangzhou, November 5 – November 8, 2021, Proceedings (in press)

A multi-party non-interactive key-exchange (NIKE) scheme enables N users to securely exchange a secret key K in a non-interactive manner. It is well-known that NIKE schemes can be obtained assuming the ... [more ▼]

A multi-party non-interactive key-exchange (NIKE) scheme enables N users to securely exchange a secret key K in a non-interactive manner. It is well-known that NIKE schemes can be obtained assuming the existence of indistinguishability obfuscation (iO). In this work, we revisit the original, iO-based, provably-secure NIKE construction by Boneh and Zhandry, aiming to simplify it. The core idea behind our protocol is to replace the functionality of the obfuscator with the one of an affine determinant program (ADP). Although ADPs have been designed with the purpose of attaining indistinguishability obfuscation, such implication is left open for general circuits. The ingredients enabling to prove the security of our scheme stem into a more careful analysis of the branching programs needed to build ADPs. In particular, we show: 1) An intuitive indistinguishability notion defined for ADPs of puncturable pseudorandom functions (PRFs) is sufficient to prove security for NIKE. 2) A set of simple conditions based on ADP's branching program topology that are sufficient for proving indistinguishability of ADPs. We leave open the question of finding ADPs satisfying them. [less ▲]

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See detailAdaptively Secure Laconic Function Evaluation for NC1
Agrawal, Shweta; Rosie, Razvan UL

E-print/Working paper (2021)

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See detailPost-Quantum Secure LFE for L/poly with Smaller Parameters
Naccache, David; Rosie, Razvan UL; Spignoli, Lorenzo UL

E-print/Working paper (2021)

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See detailRobust Encryption, Extended
Geraud, Remi; Naccache, David; Rosie, Razvan UL

in Matsui, Mitsuru (Ed.) The Cryptographers' Track at the RSA Conference 2019, San Francisco, CA, USA, March 4–8, 2019, Proceedings (2019, March 01)

Robustness is a notion often tacitly assumed while working with encrypted data. Roughly speaking, it states that a ciphertext cannot be decrypted under different keys. Initially formalized in a public-key ... [more ▼]

Robustness is a notion often tacitly assumed while working with encrypted data. Roughly speaking, it states that a ciphertext cannot be decrypted under different keys. Initially formalized in a public-key context, it has been further extended to key-encapsulation mechanisms, and more recently to pseudorandom functions, message authentication codes and authenticated encryption. In this work, we motivate the importance of establishing similar guarantees for functional encryption schemes, even under adversarially generated keys. Our main security notion is intended to capture the scenario where a ciphertext obtained under a master key (corresponding to Authority 1) is decrypted by functional keys issued under a different master key (Authority 2). Furthermore, we show there exist simple functional encryption schemes where robustness under adversarial key-generation is not achieved. As a secondary and independent result, we formalize robustness for digital signatures – a signature should not verify under multiple keys – and point out that certain signature schemes are not robust when the keys are adversarially generated. We present simple, generic transforms that turn a scheme into a robust one, while maintaining the original scheme’s security. For the case of public-key functional encryption, we look into ciphertext anonymity and provide a transform achieving it. [less ▲]

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See detailNew Constructions of Verifiable Delay Functions
Barthel, Jim Jean-Pierre UL; Rosie, Razvan UL

E-print/Working paper (n.d.)

Detailed reference viewed: 114 (10 UL)