Privacy Pass

Warning: This library has not been independently audited. It should not be used in production without a professional security review.

A Rust implementation of the Privacy Pass issuance protocols. The library implements both client and server sides with an async API.

Protocols

Token type	Spec	Primitive	Cipher suites
Privately Verifiable	RFC 9578 §5	VOPRF	P384-SHA384, Ristretto255-SHA512
Publicly Verifiable	RFC 9578 §6	Blind RSA	RSA-2048, SHA-384, PSS
Amortized (Batch VOPRF)	draft-ietf-privacypass-batched-tokens §5	VOPRF	P384-SHA384, Ristretto255-SHA512
Generic Batch	draft-ietf-privacypass-batched-tokens §6	Mixed	All of the above

The auth module provides construction and parsing of the HTTP WWW-Authenticate / Authorization headers used in the Privacy Pass challenge-redemption flow.

Usage

Add the dependency to your Cargo.toml:

[dependencies]
privacypass = "0.2"

Privately verifiable token lifecycle (create keypair, challenge, request, issue, finalize, redeem):

use p384::NistP384;
use privacypass::{
    auth::authenticate::TokenChallenge,
    common::private::PrivateCipherSuite,
    private_tokens::{TokenRequest, server::*},
};

// Server: create a keypair
let key_store = /* NonceKeyStore implementation */;
let nonce_store = /* NonceStore implementation */;
let server = Server::new();
let public_key = server.create_keypair(&key_store).await.unwrap();

// Client: build a token request from a challenge
let challenge = TokenChallenge::new(
    NistP384::token_type(),
    "example.com",
    None,
    &["example.com".to_string()],
);
let (token_request, token_state) =
    TokenRequest::new(public_key, &challenge).unwrap();

// Server: issue a token response
let token_response = server
    .issue_token_response(&key_store, token_request)
    .await
    .unwrap();

// Client: finalize the token
let token = token_response.issue_token(&token_state).unwrap();

// Server: redeem the token
server
    .redeem_token(&key_store, &nonce_store, token)
    .await
    .unwrap();

Testing

cargo test
cargo test --all-features
cargo bench

License

This project is licensed under the MIT License.