stjordanis / vrf

Implementation of Cardano compatible VRF function

Verifiable Random Function

DISCLAIMER: this crate is under active development and should not be used.

Implementation of the verifiable random function presented in draft-irtf-cfrg-vrf-03 using Edwards25519, SHA512, and Elligator2, and that presented in draft-irtf-cfrg-vrf-09 using Edwards25519, SHA512, and Elligator2.

The goal of this crate is to a compatible implementation with the VRF-03 implemented over libsodium, and with the latest version of the standard.

Note on compatibility:

Currently, the tests pass because we are using a forked curve25519-dalek crate. The implementation of the vrf over libsodium differs in the elligator2 function. curve25519-dalek's API does not allow us to modify the elligator2 function, which makes use rely on a fork. In particular, here we clear the sign bit, when it should be cleared only here (according to the latest standards). This does not reduce the security of the scheme, but makes it incompatible with other implementations.