pakery-opaque

OPAQUE augmented PAKE protocol implementation (RFC 9807).

Part of the pakery workspace.

OPAQUE is an augmented (asymmetric) PAKE: the server stores a password verifier instead of the plaintext password. Even if the server is compromised, the attacker must perform an offline dictionary attack per user to recover passwords.

Usage

[dependencies]
pakery-opaque = "0.1"
pakery-crypto = { version = "0.1", features = ["ristretto255"] }

Example

use pakery_opaque::*;
use pakery_crypto::*;
use pakery_core::crypto::IdentityKsf;

struct MyOpaqueSuite;

impl OpaqueCiphersuite for MyOpaqueSuite {
    type Hash = Sha512Hash;
    type Kdf = HkdfSha512;
    type Mac = HmacSha512;
    type Dh = Ristretto255Dh;
    type Oprf = Ristretto255Oprf;
    type Ksf = IdentityKsf;

    const NN: usize = 32;
    const NSEED: usize = 32;
    const NOE: usize = 32;
    const NOK: usize = 32;
    const NM: usize = 64;
    const NH: usize = 64;
    const NPK: usize = 32;
    const NSK: usize = 32;
    const NX: usize = 64;
}

let mut rng = rand_core::OsRng;

// === Registration ===
let setup = ServerSetup::<MyOpaqueSuite>::new(&mut rng).unwrap();

let (reg_request, reg_state) =
    ClientRegistration::<MyOpaqueSuite>::start(b"password", &mut rng).unwrap();

let reg_response =
    ServerRegistration::<MyOpaqueSuite>::start(&setup, &reg_request, b"user@example.com")
        .unwrap();

let (record, _export_key) = reg_state.finish(&reg_response, b"", b"", &mut rng).unwrap();

// === Login ===
let (ke1, client_state) =
    ClientLogin::<MyOpaqueSuite>::start(b"password", &mut rng).unwrap();

let (ke2, server_state) = ServerLogin::<MyOpaqueSuite>::start(
    &setup, &record, &ke1, b"user@example.com",
    b"my-context", b"", b"", &mut rng,
).unwrap();

let (ke3, client_session_key, _export_key) = client_state
    .finish(&ke2, b"my-context", b"", b"").unwrap();

let server_session_key = server_state.finish(&ke3).unwrap();

assert_eq!(client_session_key, server_session_key);

Features

Security

• #![forbid(unsafe_code)]
• Constant-time comparisons via subtle
• Secret values zeroized on drop via zeroize
• Validated against RFC 9807 test vectors

MSRV

The minimum supported Rust version is 1.79.

License

Licensed under either of Apache License, Version 2.0 or MIT License at your option.