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// -*- mode: rust; -*-
//
// This file is part of x25519-dalek.
// Copyright (c) 2017-2021 isis lovecruft
// Copyright (c) 2019-2021 DebugSteven
// See LICENSE for licensing information.
//
// Authors:
// - isis agora lovecruft <isis@patternsinthevoid.net>
// - DebugSteven <debugsteven@gmail.com>
// Refuse to compile if documentation is missing, but only on nightly.
//
// This means that missing docs will still fail CI, but means we can use
// README.md as the crate documentation.
#![no_std]
#![cfg_attr(feature = "bench", feature(test))]
#![cfg_attr(feature = "nightly", deny(missing_docs))]
#![doc(html_logo_url = "https://doc.dalek.rs/assets/dalek-logo-clear.png")]
#![doc(html_root_url = "https://docs.rs/x25519-dalek/1.2.0")]
//! # x25519-dalek [](https://crates.io/crates/x25519-dalek) [](https://docs.rs/x25519-dalek) [](https://travis-ci.org/dalek-cryptography/x25519-dalek)
//!
//! A pure-Rust implementation of x25519 elliptic curve Diffie-Hellman key exchange,
//! with curve operations provided by
//! [curve25519-dalek](https://github.com/dalek-cryptography/curve25519-dalek).
//!
//! This crate provides two levels of API: a bare byte-oriented `x25519`
//! function which matches the function specified in [RFC7748][rfc7748], as
//! well as a higher-level Rust API for static and ephemeral Diffie-Hellman.
//!
//! ## Examples
//!
//! <a href="https://shop.bubblesort.io">
//! <img
//! style="float: right; width: auto; height: 300px;"
//! src="https://raw.githubusercontent.com/dalek-cryptography/x25519-dalek/master/res/bubblesort-zines-secret-messages-cover.jpeg"/>
//! </a>
//!
//! Alice and Bob are two adorable kittens who have lost their mittens, and they
//! wish to be able to send secret messages to each other to coordinate finding
//! them, otherwise—if their caretaker cat finds out—they will surely be called
//! naughty kittens and be given no pie!
//!
//! But the two kittens are quite clever. Even though their paws are still too big
//! and the rest of them is 90% fuzziness, these clever kittens have been studying
//! up on modern public key cryptography and have learned a nifty trick called
//! *elliptic curve Diffie-Hellman key exchange*. With the right incantations, the
//! kittens will be able to secretly organise to find their mittens, and then spend
//! the rest of the afternoon nomming some yummy pie!
//!
//! First, Alice uses `EphemeralSecret::new()` and then
//! `PublicKey::from()` to produce her secret and public keys:
//!
//! ```rust
//! use rand_core::OsRng;
//! use x25519_dalek::{EphemeralSecret, PublicKey};
//!
//! let alice_secret = EphemeralSecret::new(OsRng);
//! let alice_public = PublicKey::from(&alice_secret);
//! ```
//!
//! Bob does the same:
//!
//! ```rust
//! # use rand_core::OsRng;
//! # use x25519_dalek::{EphemeralSecret, PublicKey};
//! let bob_secret = EphemeralSecret::new(OsRng);
//! let bob_public = PublicKey::from(&bob_secret);
//! ```
//!
//! Alice meows across the room, telling `alice_public` to Bob, and Bob
//! loudly meows `bob_public` back to Alice. Alice now computes her
//! shared secret with Bob by doing:
//!
//! ```rust
//! # use rand_core::OsRng;
//! # use x25519_dalek::{EphemeralSecret, PublicKey};
//! # let alice_secret = EphemeralSecret::new(OsRng);
//! # let alice_public = PublicKey::from(&alice_secret);
//! # let bob_secret = EphemeralSecret::new(OsRng);
//! # let bob_public = PublicKey::from(&bob_secret);
//! let alice_shared_secret = alice_secret.diffie_hellman(&bob_public);
//! ```
//!
//! Similarly, Bob computes a shared secret by doing:
//!
//! ```rust
//! # use rand_core::OsRng;
//! # use x25519_dalek::{EphemeralSecret, PublicKey};
//! # let alice_secret = EphemeralSecret::new(OsRng);
//! # let alice_public = PublicKey::from(&alice_secret);
//! # let bob_secret = EphemeralSecret::new(OsRng);
//! # let bob_public = PublicKey::from(&bob_secret);
//! let bob_shared_secret = bob_secret.diffie_hellman(&alice_public);
//! ```
//!
//! These secrets are the same:
//!
//! ```rust
//! # use rand_core::OsRng;
//! # use x25519_dalek::{EphemeralSecret, PublicKey};
//! # let alice_secret = EphemeralSecret::new(OsRng);
//! # let alice_public = PublicKey::from(&alice_secret);
//! # let bob_secret = EphemeralSecret::new(OsRng);
//! # let bob_public = PublicKey::from(&bob_secret);
//! # let alice_shared_secret = alice_secret.diffie_hellman(&bob_public);
//! # let bob_shared_secret = bob_secret.diffie_hellman(&alice_public);
//! assert_eq!(alice_shared_secret.as_bytes(), bob_shared_secret.as_bytes());
//! ```
//!
//! Voilà! Alice and Bob can now use their shared secret to encrypt their
//! meows, for example, by using it to generate a key and nonce for an
//! authenticated-encryption cipher.
//!
//! This example used the ephemeral DH API, which ensures that secret keys
//! cannot be reused; Alice and Bob could instead use the static DH API
//! and load a long-term secret key.
//!
//! # Installation
//!
//! To install, add the following to your project's `Cargo.toml`:
//!
//! ```toml
//! [dependencies]
//! x25519-dalek = "1"
//! ```
//!
//! # MSRV
//!
//! Current MSRV is 1.41 for production builds, and 1.48 for running tests.
//!
//! # Documentation
//!
//! Documentation is available [here](https://docs.rs/x25519-dalek).
//!
//! # Note
//!
//! This code matches the [RFC7748][rfc7748] test vectors.
//! The elliptic curve
//! operations are provided by `curve25519-dalek`, which makes a best-effort
//! attempt to prevent software side-channels.
//!
//! "Secret Messages" cover image and [zine](https://shop.bubblesort.io/products/secret-messages-zine)
//! copyright © Amy Wibowo ([@sailorhg](https://twitter.com/sailorhg))
//!
//! [rfc7748]: https://tools.ietf.org/html/rfc7748
//!
//! # See also
//!
//! - [crypto_box]: pure Rust public-key authenticated encryption compatible with
//! the NaCl family of encryption libraries (libsodium, TweetNaCl) which uses
//! `x25519-dalek` for key agreement
//!
//! [crypto_box]: https://github.com/RustCrypto/AEADs/tree/master/crypto_box
extern crate curve25519_dalek;
extern crate rand_core;
extern crate zeroize;
mod x25519;
pub use crate::x25519::*;