An Identity-Based Group Signature with Membership Revocation in the Standard Model

Group signatures allow group members to sign an arbitrary number\ud of messages on behalf of the group without revealing their\ud identity. Under certain circumstances the group manager holding a\ud tracing key can reveal the identity of the signer from the\ud signature. Practical group signature schemes should support\ud membership revocation where the revoked member loses the\ud capability to sign a message on behalf of the group without\ud influencing the other non-revoked members. A model known as\ud \emph{verifier-local revocation} supports membership revocation.\ud In this model the trusted revocation authority sends revocation\ud messages to the verifiers and there is no need for the trusted\ud revocation authority to contact non-revoked members to update\ud their secret keys. Previous constructions of verifier-local\ud revocation group signature schemes either have a security proof in the\ud random oracle model or are non-identity based. A security proof\ud in the random oracle model is only a heuristic proof and\ud non-identity-based group signature suffer from standard Public Key\ud Infrastructure (PKI) problems, i.e. the group public key is not\ud derived from the group identity and therefore has to be certified.\ud \ud \ud In this work we construct the first verifier-local revocation group\ud signature scheme which is identity-based and which has a security proof in the standard model. In\ud particular, we give a formal security model for the proposed\ud scheme and prove that the scheme has the\ud property of selfless-anonymity under the decision Linear (DLIN)\ud assumption and it is fully-traceable under the\ud Computation Diffie-Hellman (CDH) assumption. The proposed scheme is based on prime order bilinear\ud groups

Efficient Multi-Party Contact Tracing

Since the beginning of the Covid-19 Pandemic, many Countries adopted Contact Tracing Apps as an automatic way to trace if someone has been in contact with a Covid-19 patient. However, most existing solutions consider two party settings only. Since many people meet at the same time in real-life scenarios, one cannot extend current schemes to multi-party settings because they will not scale well and burden the device. In this paper, we propose a new contact tracing protocol that works in a multi-party setting. We evaluate our scheme to show its efficiency.M. de Goyon, A. Miyaji and Y. Tian, "Efficient Multi-Party Contact Tracing," in 2021 Ninth International Symposium on Computing and Networking (CANDAR), Matsue, Japan, 2021 pp. 10-18. doi: 10.1109/CANDAR53791.2021.00010

An Online English Auction Scheme

Online English auction is most familiar and mostly used online auction process in the present scenario. It is the most efficient auction process which gives most desirable results in terms of revenue . Our scheme involves three parties, namely the Registration Manager(RM), Auction Manager(AM), and Bidder(B). The Registration Manager publicizes the parameters to register the bidders, allowing them to participate in the bidding process. It also protects the bidding rights and manages the information on the key. The Auction Manager is responsible for conducting the bidding after the registration is over. Our proposed scheme satisfies the following features such as anonymity, no framing, unforgeability, non-repudiation, fairness, public verifiability, one-time registration, and easy revocation. The scheme uses Discrete Logarithmic Problem (DLP) and Secure Hash Algorithm (SHA-1) as hash function

Online English Auction Scheme

Online English auction is most familiar and mostly used online auction process in the present scenario. It is the most efficient auction process which gives most desirable results in terms of revenue. Our scheme involves three parties, namely the Registration Manager(RM), Auction Manager(AM), and Bidder(B). The Registration Manager publicizes the parameters to register the bidders, allowing them to participate in the bidding process. It also protects the bidding rights and manages the information on the key. The Auction Manager is responsible for conducting the bidding after the registration is over. Our proposed scheme satisfies the following features such as anonymity, no framing, unforgeability, non-repudiation, fairness, public verifiability, one-time registration, and easy revocation. The scheme uses Discrete Logarithmic Problem (DLP) and Secure Hash Algorithm (SHA-1) as hash function

An Electronic Auction Scheme Based on Group Signatures and Partially Blind Signatures

AbstractA new electronic auction scheme is proposed based on group signatures and partially blind signatures. At the same security strengthen, an optimization was done on the processes of electronic auction scheme and the dependence on trusted third party was reduced, moreover, multiple goods is auctioned at the same time, therefore, this scheme suited to large-scale electronic auction. Furthermore, due to application of vickrey auctions, the principle of optimal allocation of goods is easily satisfied