chore: update README

README.md

@@ -1,13 +1,85 @@
 # Privacy Pass
 
-A Rust implementation of the Privacy Pass protocols as specified in the Privacy
-Pass IETF WG
-[documents](https://datatracker.ietf.org/wg/privacypass/documents/).
+> **Warning:** This library has not been independently audited. It should
+> not be used in production without a professional security review.
 
-The library implements both the server side and the client side components
-for the following token types:
+A Rust implementation of the [Privacy Pass](https://datatracker.ietf.org/wg/privacypass/documents/)
+issuance protocols. The library implements both client and server sides
+with an async API.
 
- - Privately Verifiable Tokens
- - Publicly Verifiable Tokens
- - Amortized Tokens
- - Generic Tokens
+## Protocols
+
+| Token type | Spec | Primitive | Cipher suites |
+|---|---|---|---|
+| Privately Verifiable | [RFC 9578 §5](https://www.rfc-editor.org/rfc/rfc9578.html#section-5) | VOPRF | P384-SHA384, Ristretto255-SHA512 |
+| Publicly Verifiable | [RFC 9578 §6](https://www.rfc-editor.org/rfc/rfc9578.html#section-6) | Blind RSA | RSA-2048, SHA-384, PSS |
+| Amortized (Batch VOPRF) | [draft-ietf-privacypass-batched-tokens §5](https://www.ietf.org/archive/id/draft-ietf-privacypass-batched-tokens-04.html#section-5) | VOPRF | P384-SHA384, Ristretto255-SHA512 |
+| Generic Batch | [draft-ietf-privacypass-batched-tokens §6](https://www.ietf.org/archive/id/draft-ietf-privacypass-batched-tokens-04.html#section-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`:
+
+```toml
+[dependencies]
+privacypass = "0.2"
+```
+
+Privately verifiable token lifecycle (create keypair, challenge, request,
+issue, finalize, redeem):
+
+```rust
+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
+
+```sh
+cargo test
+cargo test --all-features
+cargo bench
+```
+
+## License
+
+This project is licensed under the [MIT License](LICENSE).