conference paper
Circular Security Reconsidered
2016
Innovative Security Solutions for Information Technology and Communications
The notion of circular security of pseudorandom functions (PRF) was introduced in Distance Bounding Protocols. So far, only a construction based on a random oracle model was proposed. Circular security stands between two new notions which we call Key Dependent Feedback (KDF) security and Leak security. So far, only a construction based on a random oracle was proposed. We give an algebraic construction based on a q-DDH assumpsion. We first prove that a small-domain Verifiable Random Functions (VRF) from Dodis-Yampolskiy is a circular secure PRF. We then use the extension to large-domain VRF by augmented cascading by Boneh et. al. This gives the first construction in the standard model.