International Association
for Cryptologic Research

We review the two RSA-based accumulators introduced by Camenisch and Lysyanskaya in 2002 in the setting of revocation for anonymous credential schemes, such as Idemix or BBS+. We show that in such a setting, the lower and upper bounds placed on the accumulated values in the paper are unnecessarily strict; they can be removed almost entirely (up to the group order of the credential scheme). This allows the accumulators to be used on elliptic curves of ordinary sizes, such as the ones on which BBS+ is commonly implemented. We also offer some notes and optimizations for implementations of anonymous credential schemes that use these accumulators to enable revocation.