* liboprf

This library implements the basic OPRF(ristretto255, SHA-512) variant
from the IRTF CFRG Draft: https://github.com/cfrg/draft-irtf-cfrg-voprf/

Additionally it implements a threshold OPRF based on
https://eprint.iacr.org/2017/363 by Krawczyk et al.

This library depends on libsodium.
