diff --git a/Cargo.toml b/Cargo.toml index 2604de3..0871841 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -5,6 +5,7 @@ edition = "2018" # - update version in README.md # - update html_root_url # - update CHANGELOG +# - if any changes were made to README.md, mirror them in src/lib.rs docs version = "1.1.1" authors = [ "Isis Lovecruft ", diff --git a/src/lib.rs b/src/lib.rs index 845538b..e5f7bfe 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -17,12 +17,139 @@ #![no_std] #![cfg_attr(feature = "bench", feature(test))] #![cfg_attr(feature = "nightly", deny(missing_docs))] -#![cfg_attr(feature = "nightly", doc = include_str!("../README.md"))] #![doc(html_logo_url = "https://doc.dalek.rs/assets/dalek-logo-clear.png")] #![doc(html_root_url = "https://docs.rs/x25519-dalek/1.1.1")] -//! Note that docs will only build on nightly Rust until -//! `feature(external_doc)` is stabilized. +//! # x25519-dalek [![](https://img.shields.io/crates/v/x25519-dalek.svg)](https://crates.io/crates/x25519-dalek) [![](https://docs.rs/x25519-dalek/badge.svg)](https://docs.rs/x25519-dalek) [![](https://travis-ci.org/dalek-cryptography/x25519-dalek.svg?branch=master)](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 +//! +//! +//! +//! +//! +//! 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 = "1.1" +//! ``` +//! +//! # 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;