1Caulk: Lookup Arguments in Sublinear Time Arantxa Zapico∗1, Vitalik Buterin2, Dmitry Khovratovich2, Mary Maller2, Anca Nitulescu3, and Mark Simkin2 1 Universitat Pompeu Fabra† 2 Ethereum Foundation‡ 3 Protocol Labs§ Abstract We present position-hiding linkability for vector commitment schemes: one can prove in zero knowledge that one or m values that comprise commitment cm all belong to the vector of size N committed to in C. Our construction Caulk can be used for membership proofs and looku...