3 research outputs found

    A Unlinkable Delegation-based Authentication Protocol with Users’ Non-repudiation for Portable Communication Systems

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    [[abstract]]For portable communication systems, the delegation-based authentication protocol provides efficient subsequent login authentication, data confidentiality, user privacy protection, and non-repudiation. However, in all proposed protocols, the non-repudiation of mobile users is based on an unreasonable assumption that home location registers are always trusted. To weaken this assumption and enhance the nonrepudiation of mobile users, a new delegation-based authentication protocol is proposed. The new protocol also removes the exhaustive search problem of the subsequent login authentication to improve the subsequent login authentication performance. Moreover, the user unlinkability in the subsequent login authentication is also provided to enhance the user identity privacy protection.[[incitationindex]]EI[[incitationindex]]CEPS[[booktype]]紙

    Identity Based Self Delegated Signature - Self Proxy Signatures

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    A proxy signature scheme is a variant of digital signature scheme in which a signer delegates his signing rights to another person called proxy signer, so that the proxy signer can generate the signature of the actual signer in his absence. Self Proxy Signature (SPS) is a type of proxy signature wherein, the original signer delegates the signing rights to himself (Self Delegation), there by generating temporary public and private key pairs for himself. Thus, in SPS the user can prevent the exposure of his private key from repeated use. In this paper, we propose the first identity based self proxy signature scheme. We give a generic scheme and a concrete instantiation in the identity based setting. We have defined the appropriate security model for the same and proved both the generic and identity based schemes in the defined security model

    CONSTRUCTION OF EFFICIENT AUTHENTICATION SCHEMES USING TRAPDOOR HASH FUNCTIONS

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    In large-scale distributed systems, where adversarial attacks can have widespread impact, authentication provides protection from threats involving impersonation of entities and tampering of data. Practical solutions to authentication problems in distributed systems must meet specific constraints of the target system, and provide a reasonable balance between security and cost. The goal of this dissertation is to address the problem of building practical and efficient authentication mechanisms to secure distributed applications. This dissertation presents techniques to construct efficient digital signature schemes using trapdoor hash functions for various distributed applications. Trapdoor hash functions are collision-resistant hash functions associated with a secret trapdoor key that allows the key-holder to find collisions between hashes of different messages. The main contributions of this dissertation are as follows: 1. A common problem with conventional trapdoor hash functions is that revealing a collision producing message pair allows an entity to compute additional collisions without knowledge of the trapdoor key. To overcome this problem, we design an efficient trapdoor hash function that prevents all entities except the trapdoor key-holder from computing collisions regardless of whether collision producing message pairs are revealed by the key-holder. 2. We design a technique to construct efficient proxy signatures using trapdoor hash functions to authenticate and authorize agents acting on behalf of users in agent-based computing systems. Our technique provides agent authentication, assurance of agreement between delegator and agent, security without relying on secure communication channels and control over an agent’s capabilities. 3. We develop a trapdoor hash-based signature amortization technique for authenticating real-time, delay-sensitive streams. Our technique provides independent verifiability of blocks comprising a stream, minimizes sender-side and receiver-side delays, minimizes communication overhead, and avoids transmission of redundant information. 4. We demonstrate the practical efficacy of our trapdoor hash-based techniques for signature amortization and proxy signature construction by presenting discrete log-based instantiations of the generic techniques that are efficient to compute, and produce short signatures. Our detailed performance analyses demonstrate that the proposed schemes outperform existing schemes in computation cost and signature size. We also present proofs for security of the proposed discrete-log based instantiations against forgery attacks under the discrete-log assumption
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