Quantum Homomorphic Signature with Repeatable Verification

In January 2015,the first quantum homomorphic signature scheme was proposed creatively.However,only one verifier is allowed to verify a signature once in this scheme.In order to support repeatable verification for general scenario,we propose a new quantum homomorphic signature scheme with repeatable verification by introducing serial verification model and parallel verification model.Serial verification model solves the problem of signature verification by combining key distribution and Bell measurement.Parallel verification model solves the problem of signature duplication by logically treating one particle of an EPR pair as a quantum signature and physically preparing a new EPR pair.These models will be beneficial to the signature verification of general scenarios.Scheme analysis shows that both intermediate verifiers and terminal verifiers can successfully verify signatures in the same operation with fewer resource consumption,and especially the verified signature in entangled states can be used repeatedly.

A Linear Homomorphic Proxy Signature Scheme Based on Blockchain for Internet of Things

The mushroom growth of IoT has been accompanied by the generation of massive amounts of data.Subject to the limited storage and computing capabilities ofmost IoT devices,a growing number of institutions and organizations outsource their data computing tasks to cloud servers to obtain efficient and accurate computation while avoiding the cost of local data computing.One of the most important challenges facing outsourcing computing is how to ensure the correctness of computation results.Linearly homomorphic proxy signature(LHPS)is a desirable solution to ensure the reliability of outsourcing computing in the case of authorized signing right.Blockchain has the characteristics of tamper-proof and traceability,and is a new technology to solve data security.However,as far as we know,constructions of LHPS have been few and far between.In addition,the existing LHPS scheme does not focus on homomorphic unforgeability and does not use blockchain technology.Herein,we improve the security model of the LHPS scheme,and the usual existential forgery and homomorphic existential forgery of two types of adversaries are considered.Under the new model,we present a blockchain-based LHPS scheme.The security analysis shows that under the adaptive chosen message attack,the unforgeability of the proposed scheme can be reduced to the CDH hard assumption,while achieving the usual and homomorphic existential unforgeability.Moreover,comparedwith the previous LHPS scheme,the performance analysis shows that our scheme has the same key size and comparable computational overhead,but has higher security.