An Improved Elegant Method to Re-initialize Hash Chains

Hash chains are widely used in various cryptographic systems such as electronic micropayments and one-time passwords etc. However, hash chains suffer from the limitation that they have a finite number of links which when used up requires the system to re-initialize new hash chains. So system design has to reduce the overhead when hash chains are re-initialized. Recently, Vipul Goyal proposed an elegant one-time-signature-based method to re-initialize hash chains, in this efficient method an infinite number of finite length hash chains can be tied together so that hash chains can be securely re-initialized in a non-repudiable manner. Vipul Goyal¡¯s method is improved in this paper to reach a little more efficient method, which, more importantly, is a natural extension of the concept of conventional hash chains

An Improved Elegant Method to Re-initialize Hash Chains

Abstract: Hash chains are widely used in various cryptographic systems such as electronic micropayments and one-time passwords etc. However, hash chains suffer from the limitation that they have a finite number of links which when used up requires the system to re-initialize new hash chains. So system design has to reduce the overhead when hash chains are re-initialized. Recently, Vipul Goyal proposed an elegant one-time-signature-based method to re-initialize hash chains, in this efficient method an infinite number of finite length hash chains can be tied together so that hash chains can be securely re-initialized in a non-repudiable manner. Vipul Goyal’s method is improved in this paper to reach a little more efficient method, which, more importantly, is a natural extension of the concept of conventional hash chains. Key words: Hash chain, One-time signature, Non-repudiability

Security mechanisms for next-generation mobile networks

Basic concepts and definitions -- Motivation and research challenges -- Research objectives -- Mobile value-added service access -- UMTS access security -- DoS attacks in mobile networks -- A lightweight mobile service access based on reusable tickets -- Background work and motivation -- Service access through tickets -- System security analysis -- Comparisons with related work -- Enhancing UMTS AKA with vector combination -- Overview of UMTS AKA -- UMTS AKA weaknesses- -- Vector combination based AKA -- Security analysis of VC-AKA -- Mobility-oriented AKA in UMTS -- Mobility-oriented authentication -- Security analysis of MO-AKA -- A fine-grained puzzle against DOS attacks -- Quasi partial collision -- Fine-grained control over difficulties -- Lightweight to mobile devices -- Against replay attacks -- Confidentiality, integrity and user privacy