Fischlin, Marc ; Rohrbach, Felix ; Schmalz, Tobias (2022)
A Random Oracle for All of Us.
13th International Conference on Cryptology in Africa (AFRICACRYPT 2022). Fes, Morocco (18.-20.07.2022)
doi: 10.1007/978-3-031-17433-9_20
Konferenzveröffentlichung, Bibliographie
Kurzbeschreibung (Abstract)
We introduce the notion of a universal random oracle. Analogously to a classical random oracle it idealizes hash functions as random functions. However, as opposed to a classical random oracle which is created freshly and independently for each adversary, the universal random oracle should provide security of a cryptographic protocol against all adversaries simultaneously. This should even hold if the adversary now depends on the random function. This reflects better the idea that the strong hash functions like SHA-2 and SHA-3 are fixed before the adversary decides upon the attack strategy.
Besides formalizing the notion of the universal random oracle model we show that the model is asymptotically equivalent to Unruh’s auxiliary-input random oracle model (Crypto 2007). In Unruh’s model the adversary receives some inefficiently computed information about the random oracle as extra input. Noteworthy, while security in the universal random oracle model implies security in the auxiliary-input random oracle model tightly, the converse implication introduces an inevitable security loss. This implies that the universal random oracle model provides stronger guarantees in terms of concrete security. Validating the model we finally show, via a direct proof with concrete security, that a universal random oracle is one-way.
| Typ des Eintrags: | Konferenzveröffentlichung |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Fischlin, Marc ; Rohrbach, Felix ; Schmalz, Tobias |
| Art des Eintrags: | Bibliographie |
| Titel: | A Random Oracle for All of Us |
| Sprache: | Englisch |
| Publikationsjahr: | 6 Oktober 2022 |
| Verlag: | Springer |
| Buchtitel: | Progress in Cryptology - AFRICACRYPT 2022 |
| Reihe: | Lecture Notes in Computer Science |
| Band einer Reihe: | 13503 |
| Veranstaltungstitel: | 13th International Conference on Cryptology in Africa (AFRICACRYPT 2022) |
| Veranstaltungsort: | Fes, Morocco |
| Veranstaltungsdatum: | 18.-20.07.2022 |
| DOI: | 10.1007/978-3-031-17433-9_20 |
| URL / URN: | https://link.springer.com/chapter/10.1007/978-3-031-17433-9_... |
| Zugehörige Links: | |
| Kurzbeschreibung (Abstract): | We introduce the notion of a universal random oracle. Analogously to a classical random oracle it idealizes hash functions as random functions. However, as opposed to a classical random oracle which is created freshly and independently for each adversary, the universal random oracle should provide security of a cryptographic protocol against all adversaries simultaneously. This should even hold if the adversary now depends on the random function. This reflects better the idea that the strong hash functions like SHA-2 and SHA-3 are fixed before the adversary decides upon the attack strategy. Besides formalizing the notion of the universal random oracle model we show that the model is asymptotically equivalent to Unruh’s auxiliary-input random oracle model (Crypto 2007). In Unruh’s model the adversary receives some inefficiently computed information about the random oracle as extra input. Noteworthy, while security in the universal random oracle model implies security in the auxiliary-input random oracle model tightly, the converse implication introduces an inevitable security loss. This implies that the universal random oracle model provides stronger guarantees in terms of concrete security. Validating the model we finally show, via a direct proof with concrete security, that a universal random oracle is one-way. |
| Freie Schlagworte: | Solutions, S4 |
| Fachbereich(e)/-gebiet(e): | 20 Fachbereich Informatik 20 Fachbereich Informatik > Kryptographie und Komplexitätstheorie DFG-Sonderforschungsbereiche (inkl. Transregio) DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche Profilbereiche Profilbereiche > Cybersicherheit (CYSEC) Forschungsfelder Forschungsfelder > Information and Intelligence Forschungsfelder > Information and Intelligence > Cybersecurity & Privacy DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 1119: CROSSING – Kryptographiebasierte Sicherheitslösungen als Grundlage für Vertrauen in heutigen und zukünftigen IT-Systemen |
| Hinterlegungsdatum: | 21 Mär 2023 09:59 |
| Letzte Änderung: | 02 Aug 2023 14:39 |
| PPN: | 509757367 |
| Zugehörige Links: | |
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