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 $L_R$, 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 string model (without any random oracle), and soundness is achieved in the \emph{non-programmable} random oracle model. The concrete computational complexity of the transform is only slightly higher than the original Fiat-Shamir transform.
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