The Experts below are selected from a list of 24444 Experts worldwide ranked by ideXlab platform

Victor Shoup - One of the best experts on this subject based on the ideXlab platform.

  • The Twin Diffie–Hellman Problem and Applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie–Hellman Problem . This Problem is closely related to the usual (Computational) Diffie–Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie–Hellman Problem. Moreover, the twin Diffie–Hellman Problem is at least as hard as the ordinary Diffie–Hellman Problem. However, we are able to show that the twin Diffie–Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem—this is a feature not enjoyed by the Diffie–Hellman Problem, in general. Specifically, we show how to build a certain “trapdoor test” that allows us to effectively answer decision oracle queries for the twin Diffie–Hellman Problem without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie–Hellman Problem is hard. We present several other applications as well, including a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer–Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh–Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • The twin diffie-hellman Problem and applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem . This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem — this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain “trapdoor test” which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • EUROCRYPT - The twin Diffie-Hellman Problem and applications
    Advances in Cryptology – EUROCRYPT 2008, 2008
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem. This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem -- this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain "trapdoor test" which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman's non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

Laurence T. Maloney - One of the best experts on this subject based on the ideXlab platform.

  • Surface color perception and equivalent illumination models
    Journal of Vision, 2011
    Co-Authors: David H. Brainard, Laurence T. Maloney
    Abstract:

    Vision provides information about the properties and identity of objects. The ease with which we perceive object properties belies the difficulty of the underlying information-processing task. In the case of object color, retinal information about object reflectance is confounded with information about the illumination as well as about the object's shape and pose. There is no obvious rule that allows transformation of the retinal image to a color representation that depends primarily on object surface reflectance. Under many circumstances, however, object color appearance is remarkably stable across scenes in which the object is viewed. Here, we review a line of experiments and theory that aim to understand how the visual system stabilizes object color appearance. Our emphasis is on models derived from explicit analysis of the Computational Problem of estimating the physical properties of illuminants and surfaces from the retinal image, and experiments that test these models. We argue that this approach has considerable promise for allowing generalization from simplified laboratory experiments to richer scenes that more closely approximate natural viewing. We discuss the relation between the work we review and other theoretical approaches available in the literature.

  • Surface color perception and light field estimation in 3D scenes
    Vision in 3D environments, 2010
    Co-Authors: Laurence T. Maloney, He Gerhard, Huseyin Boyaci, Katja Doerschner
    Abstract:

    Previous research on surface color perception has typically used Mondrian stimuli consisting of a small number of matte surface patches in a plane perpendicular to the line of sight. In such scenes, reliable estimation of the color of a surface is a difficult if not impossible Computational Problem (Maloney, 1999). In three-dimensional scenes consisting of surfaces at many different orientations it is at least in theory possible to estimate surface color. However, the difficulty of the Problem increases, in part, be- cause the effective illumination incident on each surface (the light field) now depends on surface orientation and location. We review recent work in multiple laboratories that examines the degree to which the human visual system discounts the light field in judging matte surface lightness and color and how the visual system estimates the flow of light in a scene.

  • Surface color perception in three-dimensional scenes
    Visual Neuroscience, 2006
    Co-Authors: Huseyin Boyaci, Katja Doerschner, Jacqueline L. Snyder, Laurence T. Maloney
    Abstract:

    Researchers studying surface color perception have typically used stimuli that consist of a small number of matte patches (real or simulated) embedded in a plane perpendicular to the line of sight (a "Mondrian," Land & McCann, 1971). Reliable estimation of the color of a matte surface is a difficult if not impossible Computational Problem in such limited scenes (Maloney, 1999). In more realistic, three-dimensional scenes the difficulty of the Problem increases, in part, because the effective illumination incident on the surface (the light field) now depends on surface orientation and location. We review recent work in multiple laboratories that examines (1) the degree to which the human visual system discounts the light field in judging matte surface lightness and color and (2) what illuminant cues the visual system uses in estimating the flow of light in a scene.

David Cash - One of the best experts on this subject based on the ideXlab platform.

  • The Twin Diffie–Hellman Problem and Applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie–Hellman Problem . This Problem is closely related to the usual (Computational) Diffie–Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie–Hellman Problem. Moreover, the twin Diffie–Hellman Problem is at least as hard as the ordinary Diffie–Hellman Problem. However, we are able to show that the twin Diffie–Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem—this is a feature not enjoyed by the Diffie–Hellman Problem, in general. Specifically, we show how to build a certain “trapdoor test” that allows us to effectively answer decision oracle queries for the twin Diffie–Hellman Problem without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie–Hellman Problem is hard. We present several other applications as well, including a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer–Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh–Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • The twin diffie-hellman Problem and applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem . This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem — this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain “trapdoor test” which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • EUROCRYPT - The twin Diffie-Hellman Problem and applications
    Advances in Cryptology – EUROCRYPT 2008, 2008
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem. This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem -- this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain "trapdoor test" which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman's non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

Katja Doerschner - One of the best experts on this subject based on the ideXlab platform.

  • Surface color perception and light field estimation in 3D scenes
    Vision in 3D environments, 2010
    Co-Authors: Laurence T. Maloney, He Gerhard, Huseyin Boyaci, Katja Doerschner
    Abstract:

    Previous research on surface color perception has typically used Mondrian stimuli consisting of a small number of matte surface patches in a plane perpendicular to the line of sight. In such scenes, reliable estimation of the color of a surface is a difficult if not impossible Computational Problem (Maloney, 1999). In three-dimensional scenes consisting of surfaces at many different orientations it is at least in theory possible to estimate surface color. However, the difficulty of the Problem increases, in part, be- cause the effective illumination incident on each surface (the light field) now depends on surface orientation and location. We review recent work in multiple laboratories that examines the degree to which the human visual system discounts the light field in judging matte surface lightness and color and how the visual system estimates the flow of light in a scene.

  • Surface color perception in three-dimensional scenes
    Visual Neuroscience, 2006
    Co-Authors: Huseyin Boyaci, Katja Doerschner, Jacqueline L. Snyder, Laurence T. Maloney
    Abstract:

    Researchers studying surface color perception have typically used stimuli that consist of a small number of matte patches (real or simulated) embedded in a plane perpendicular to the line of sight (a "Mondrian," Land & McCann, 1971). Reliable estimation of the color of a matte surface is a difficult if not impossible Computational Problem in such limited scenes (Maloney, 1999). In more realistic, three-dimensional scenes the difficulty of the Problem increases, in part, because the effective illumination incident on the surface (the light field) now depends on surface orientation and location. We review recent work in multiple laboratories that examines (1) the degree to which the human visual system discounts the light field in judging matte surface lightness and color and (2) what illuminant cues the visual system uses in estimating the flow of light in a scene.

Eike Kiltz - One of the best experts on this subject based on the ideXlab platform.

  • The Twin Diffie–Hellman Problem and Applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie–Hellman Problem . This Problem is closely related to the usual (Computational) Diffie–Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie–Hellman Problem. Moreover, the twin Diffie–Hellman Problem is at least as hard as the ordinary Diffie–Hellman Problem. However, we are able to show that the twin Diffie–Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem—this is a feature not enjoyed by the Diffie–Hellman Problem, in general. Specifically, we show how to build a certain “trapdoor test” that allows us to effectively answer decision oracle queries for the twin Diffie–Hellman Problem without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie–Hellman Problem is hard. We present several other applications as well, including a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer–Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh–Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • The twin diffie-hellman Problem and applications
    Journal of Cryptology, 2009
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem . This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem — this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain “trapdoor test” which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman’s non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.

  • EUROCRYPT - The twin Diffie-Hellman Problem and applications
    Advances in Cryptology – EUROCRYPT 2008, 2008
    Co-Authors: David Cash, Eike Kiltz, Victor Shoup
    Abstract:

    We propose a new Computational Problem called the twin Diffie-Hellman Problem. This Problem is closely related to the usual (Computational) Diffie-Hellman Problem and can be used in many of the same cryptographic constructions that are based on the Diffie-Hellman Problem. Moreover, the twin Diffie-Hellman Problem is at least as hard as the ordinary Diffie-Hellman Problem. However, we are able to show that the twin Diffie-Hellman Problem remains hard, even in the presence of a decision oracle that recognizes solutions to the Problem -- this is a feature not enjoyed by the ordinary Diffie-Hellman Problem. In particular, we show how to build a certain "trapdoor test" which allows us to effectively answer such decision oracle queries, without knowing any of the corresponding discrete logarithms. Our new techniques have many applications. As one such application, we present a new variant of ElGamal encryption with very short ciphertexts, and with a very simple and tight security proof, in the random oracle model, under the assumption that the ordinary Diffie-Hellman Problem is hard. We present several other applications as well, including: a new variant of Diffie and Hellman's non-interactive key exchange protocol; a new variant of Cramer-Shoup encryption, with a very simple proof in the standard model; a new variant of Boneh-Franklin identity-based encryption, with very short ciphertexts; a more robust version of a password-authenticated key exchange protocol of Abdalla and Pointcheval.