Coconut [paper] is a distributed cryptographic signing scheme providing a high degree of privacy for its users. You can find an overview of how to use it in the Coconut section of the Nym documentation.
A simple explanation is also available in blog form.
This repo contains Go and Rust implementations of Coconut.
Note: Currently the libraries are not interoperable - different methods of curve hash are being used.
Coconut is released under the Apache-2.0 license. See inside the LICENSES folder of each project.