In this short paper, we present a Fiat-Shamir type transform that takes any Sigma protocol for a relation R and outputs a non-interactive zero-knowledge proof (not of knowledge) for the associated language LR, in the common reference string model. As in the Fiat-Shamir transform, we use a hash function H. However, zero-knowledge is achieved under standard assumptions in the common reference str...

Similarity between objects (documents, persons, answers to a questionnaire, etc.) is generally determined through relations between representations of these objects. In the case of binary representations the presence of a properly (e.g., an index term) carries a weight of one, the absence a weight of zero. In many similarity studies common zeros are ignored. This situation is called the zero in...