## The OPAQUE key exchange protocol 
[OPAQUE](https://eprint.iacr.org/2018/163.pdf) is an asymmetric password-authenticated key exchange protocol. It allows a client to authenticate to a server using a password, without ever having to expose the plaintext password to the server.
This implementation is based on the [Internet Draft for OPAQUE](https://github.com/cfrg/draft-irtf-cfrg-opaque).
Background
----------
Asymmetric Password Authenticated Key Exchange (aPAKE) protocols are designed to provide password authentication and mutually authenticated key exchange without relying on PKI (except during user/password registration) and without disclosing passwords to servers or other entities other than the client machine.
OPAQUE is a PKI-free aPAKE that is secure against pre-computation attacks and capable of using a secret salt.
Documentation
-------------
The API can be found [here](https://docs.rs/opaque-ke/) along with an example for usage.
Installation
------------
Add the following line to the dependencies of your `Cargo.toml`:
```
opaque-ke = "0.2.1"
```
Resources
---------
- [OPAQUE academic publication](https://eprint.iacr.org/2018/163.pdf), including formal definitions and a proof of security
- [draft-krawczyk-cfrg-opaque-05](https://tools.ietf.org/html/draft-krawczyk-cfrg-opaque-06), containing a specification for the OPAQUE protocol
- ["Let's talk about PAKE"](https://blog.cryptographyengineering.com/2018/10/19/lets-talk-about-pake/), an introductory blog post written by Matthew Green that covers OPAQUE
Contributors
------------
The authors of this code are Kevin Lewi
([@kevinlewi](https://github.com/kevinlewi)) and François Garillot ([@huitseeker](https://github.com/huitseeker)).
To learn more about contributing to this project, [see this document](./CONTRIBUTING.md).
#### Acknowledgments
Special thanks go to Hugo Krawczyk for helping to clarify discrepancies and making suggestions for improving
this implementation.
License
-------
This project is [MIT licensed](./LICENSE).