Browsing by Author "Ràfols, Carla"

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  • Daza, Vanesa; Herranz, Javier; Morillo, Paz; Ràfols, Carla (Elsevier, 2008)
    In a threshold broadcast encryption scheme, a sender chooses (ad-hoc) a set of n receivers and a threshold t, and then encrypts a message by using the public keys of all the receivers, in such a way that the original plaintext ...
  • Escala, Alex; Herold, Gottfried; Kiltz, Eike; Ràfols, Carla; Villar, Jorge (Springer, 2013)
    We put forward a new algebraic framework to generalize and analyze Di_e-Hellman like Decisional Assumptions which allows us to argue about security and applications by considering only algebraic properties. Our D`;k-MDDH ...
  • Attrapadung, Nuttapong; Herranz, Javier; Laguillaumie, Fabien; Libert, Benoît; De Panafieu, Elie; Ràfols, Carla (Elsevier, 2012)
    Attribute-based encryption (ABE), as introduced by Sahai and Waters, allows for fine- grained access control on encrypted data. In its key-policy flavor (the dual ciphertext-policy scenario proceeds the other way around), ...
  • Daza, Vanesa; Herranz, Javier; Morillo, Paz; Ràfols, Carla (Springer, 2007)
    In a threshold broadcast encryption scheme, a sender chooses (ad-hoc) a set of n receivers and a threshold t, and then encrypts a message by using the public keys of all the receivers, in such a way that the original ...
  • Herranz, Javier; Laguillaumie, Fabien; Ràfols, Carla (Springer, 2010)
    Attribute-based cryptography has emerged in the last years as a promising primitive for digital security. For instance, it provides good solutions to the problem of anonymous access control. In a ciphertext- policy ...
  • Escala, Alex; Herranz, Javier; Libert, Benoît; Ràfols, Carla (Springer, 2014)
    Lossy trapdoor functions, introduced by Peikert and Waters (STOC’08), have received a lot of attention in the last years, because of their wide range of applications. The notion has been recently extended to the ...
  • Morillo, Paz; Ràfols, Carla; Villar, Jorge L. (Springer, 2016)
    We put forward a new family of computational assumptions, the Kernel Matrix Diffi-Hellman Assumption. Given some matrix A sampled from some distribution D, the kernel assumption says that it is hard to find \in the ...
  • Daza, Vanesa; Morillo, Paz; Ràfols, Carla (Elsevier, 2007)
    Identity-Based cryptography has been proposed in mobile ad-hoc networks (MANETs) to provide security. However, the figure of the Private Key Generator (PKG) is not adequate in the MANET setting, since it may not be ...
  • Herold, Gottfried; Hesse, Julia; Hofheinz, Dennis; Ràfols, Carla; Rupp, Andy (Springer, 2014)
    At Eurocrypt 2010, Freeman presented a framework to convert cryptosystems based on composite-order groups into ones that use prime-order groups. Such a transformation is interesting not only from a conceptual point of ...
  • González, Alonso; Hevia, Alejandro; Ràfols, Carla (Springer, 2015)
    A sequence of recent works have constructed constant-size quasi-adaptive (QA) NIZK arguments of membership in linear subspaces of ^Gm, where ^G is a group equipped with a bilinear map e : G x H --> T. Although applicable ...
  • Herranz, Javier; Laguillaumie, Fabien; Ràfols, Carla (Elsevier, 2011)
    Semantic security and anonymity are the two main properties that an identity-based encryption scheme can satisfy. Such properties can be de ned in either an adaptive or a selective scenario, which di er on the moment ...
  • Herranz, Javier; Laguillaumie, Fabien; Libert, Benoît; Ràfols, Carla (Springer, 2012)
    Attribute-based cryptography is a natural solution for fine- grained access control with respect to security policies. In the case of attribute-based signatures (ABS), users obtain from an authority their secret keys ...
  • Ràfols, Carla (Springer, 2015)
    Groth, Ostrovsky and Sahai constructed a non-interactive Zap for NP-languages by observing that the common reference string of their proof system for circuit satisfiability admits what they call correlated key generation. ...
  • Morillo, Paz; Ràfols, Carla (Springer, 2009)
    The relation between list decoding and hard-core predicates has provided a clean and easy methodology to prove the hardness of certain predicates. So far this methodology has only been used to prove that the O(log logN) ...