This work introduces the most eﬃcient universal accumulator known today. For the ﬁrst time, we have an accumulator which does not depend on hidden order groups, does not require any exponentiations in the target group associated with the pairing function, and only requires two pairings to verify a proof-of-knowledge of a witness. We present implementations of our accumulator and another recent proposal utilizing Groth-Sahai proofs, with performance results. Our implementations are designed with cryptography agility in mind. We then build a library for revoking anonymous credentials using any accumulators, and integrated it with Microsoft U-Prove, which has a signiﬁcant contribution to an European Union’s privacy standardization eﬀort. Our work enables U-Prove revocation without compromising untraceability.