pmohassel / chl

Rust implementation of single-message credential-hiding login

Credential-Hiding Login

This Rust implementation is a research prototype of the single-message credential-hiding login protocol described in the following paper: Single-Message Credential-Hiding Login.

This prototype serves primarily as a proof of concept and benchmarking tool for our cryptographic primitive. The code has not been carefully analyzed for potential security flaws, and is not intended for use in production-level code.

Background

The typical login protocol for authenticating a user to a web service involves the client sending a password over a TLS-secured channel to the service, occasionally deployed with the password being prehashed. This widely-deployed paradigm, while simple in nature, is prone to both inadvertent logging and eavesdropping attacks, and has repeatedly led to the exposure of passwords in plaintext.

Partly to address this problem, symmetric and asymmetric PAKE protocols were developed to ensure that the messages exchanged during an authentication protocol reveal nothing about the passwords. However, these protocols inherently require at least two messages to be sent out: one from each party. This limitation hinders wider adoption, as the most common login flow consists of a single message from client to the login server. The ideal solution would retain the password privacy properties of asymmetric PAKEs while allowing the protocol to be a drop-in replacement into legacy password-over-TLS deployments.

In a credential-hiding login protocol, a client can authenticate itself by sending a single message to the server, while ensuring the correct verification of credentials and maintaining credential privacy in the same strong sense as guaranteed by asymmetric PAKEs.

Benchmarks

To run the tests and benchmarks for this library, simply run:

cargo test
cargo bench

License

This project is MIT licensed.