The Experts below are selected from a list of 15744 Experts worldwide ranked by ideXlab platform
David Pointcheval - One of the best experts on this subject based on the ideXlab platform.
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the computational and decisional diffie hellman assumptions in cryptoverif
2010Co-Authors: Bruno Blanchet, David PointchevalAbstract:We present an extension of CryptoVerif to Diffie-Hellman key agreements. CryptoVerif [1] is a security protocol verifier sound in the computational model, which produces proofs by sequences of games. CryptoVerif provides a generic method for specifying security assumptions on primitives. However, this method did not support the computational and decisional Diffie-Hellman assumptions. We have extended it to support these assumptions, which required the following additions:
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hardness of distinguishing the msb or lsb of secret keys in diffie hellman schemes
Lecture Notes in Computer Science, 2006Co-Authors: Pierre-alain Fouque, David Pointcheval, Jacques Stern, Sébastien ZimmerAbstract:In this paper we introduce very simple deterministic randomness extractors for Diffie-Hellman distributions. More specifically we show that the k most significant bits or the k least significant bits of a random element in a subgroup of Z* p are indistinguishable from a random bit-string of the same length. This allows us to show that under the Decisional Diffie-Hellman assumption we can deterministically derive a uniformly random bit-string from a Diffie-Hellman exchange in the standard model. Then, we show that it can be used in key exchange or encryption scheme to avoid the leftover hash lemma and universal hash functions.
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provably authenticated group diffie hellman key exchange the dynamic case
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange (AKE) are designed to workin a scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with "implicit" authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the litterature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with ''implicit'' authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract escholarship
2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with implicit authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
Alexandra Boldyreva - One of the best experts on this subject based on the ideXlab platform.
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Threshold Signatures , Multisignatures and Blind Signatures Based on the Gap-Diffie-Hellman-Group Signature Scheme
Public Key Cryptography (PKC 2003), 2003Co-Authors: Alexandra BoldyrevaAbstract:We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap Diffie-Hellman (GDH) group (where the Computational Diffie- Hellman problem is hard but the Decisional Diffie-Hellman problem is easy). Our constructions are based on the recently proposed GDH signature scheme of Boneh et al. [8]. Due to the instrumental structure of GDH groups and of the base scheme, it turns out that most of our constructions are simpler, more efficient and have more useful properties than similar existing constructions. We support all the proposed schemes with proofs under the appropriate computational assumptions, using the corresponding notions of security.
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efficient threshold signature multisignature and blind signature schemes based on the gap diffie hellman group signature scheme
IACR Cryptology ePrint Archive, 2002Co-Authors: Alexandra BoldyrevaAbstract:We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap Diffie-Hellman (GDH) group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy). Our constructions are based on the recently proposed GDH signature scheme of Boneh et al. [BLS]. Due to the instrumental structure of GDH groups and of the base scheme, it turns out that most of our constructions are simpler, more efficient and have more useful properties than similar existing constructions. We support all the proposed schemes with proofs under the appropriate computational assumptions, using the corresponding notions of security.
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Efficient Threshold Signature, Multisignature and Blind Signature Schemes Based on the Gap-Diffie-Hellman-group signature scheme
2002Co-Authors: Alexandra BoldyrevaAbstract:We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap Diffie-Hellman (GDH) group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy). Our constructions are based on the recently proposed GDH signature scheme of Boneh et al. [BLS]
Emmanuel Bresson - One of the best experts on this subject based on the ideXlab platform.
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provably authenticated group diffie hellman key exchange the dynamic case
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange (AKE) are designed to workin a scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with "implicit" authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the litterature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with ''implicit'' authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract escholarship
2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with implicit authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
Anton Stiglic - One of the best experts on this subject based on the ideXlab platform.
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Security Issues in the Diffie-Hellman Key Agreement Protocol
IEEE Transactions on Information Theory, 2000Co-Authors: Jean-françois Raymond, Anton StiglicAbstract:Diffie-Hellman key agreement protocol [20] implementations have been plagued by serious security flaws. The attacks can be very subtle and, more often than not, have not been taken into account by protocol designers. In this summary we discuss both theoretical attacks against the Diffie-Hellman key agreement pro-tocol and attacks based on implementation details . It is hoped that computer se-curity practitioners will obtain enough information to build and design secure and efficient versions of this classic key agreement protocol.
Olivier Chevassut - One of the best experts on this subject based on the ideXlab platform.
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provably authenticated group diffie hellman key exchange the dynamic case
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange (AKE) are designed to workin a scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with "implicit" authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the litterature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract
International Conference on the Theory and Application of Cryptology and Information Security, 2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with ''implicit'' authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
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provably authenticated group diffie hellman key exchange the dynamic case extended abstract escholarship
2001Co-Authors: Emmanuel Bresson, Olivier Chevassut, David PointchevalAbstract:Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with implicit authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
