| //! The Salsa20 stream cipher. |
| //! |
| //! Cipher functionality is accessed using traits from re-exported |
| //! [`cipher`](https://docs.rs/cipher) crate. |
| //! |
| //! # Security Warning |
| //! |
| //! This crate does not ensure ciphertexts are authentic! Thus ciphertext integrity |
| //! is not verified, which can lead to serious vulnerabilities! |
| //! |
| //! USE AT YOUR OWN RISK! |
| //! |
| //! # Diagram |
| //! |
| //! This diagram illustrates the Salsa quarter round function. |
| //! Each round consists of four quarter-rounds: |
| //! |
| //! <img src="https://raw.githubusercontent.com/RustCrypto/meta/master/img/stream-ciphers/salsa20.png" width="300px"> |
| //! |
| //! Legend: |
| //! |
| //! - ⊞ add |
| //! - ‹‹‹ rotate |
| //! - ⊕ xor |
| //! |
| //! # Usage |
| //! |
| //! ``` |
| //! use salsa20::{Salsa20, Key, Nonce}; |
| //! use salsa20::cipher::{NewCipher, StreamCipher, StreamCipherSeek}; |
| //! |
| //! let mut data = [1, 2, 3, 4, 5, 6, 7]; |
| //! |
| //! let key = Key::from_slice(b"an example very very secret key."); |
| //! let nonce = Nonce::from_slice(b"a nonce."); |
| //! |
| //! // create cipher instance |
| //! let mut cipher = Salsa20::new(&key, &nonce); |
| //! |
| //! // apply keystream (encrypt) |
| //! cipher.apply_keystream(&mut data); |
| //! assert_eq!(data, [182, 14, 133, 113, 210, 25, 165]); |
| //! |
| //! // seek to the keystream beginning and apply it again to the `data` (decrypt) |
| //! cipher.seek(0); |
| //! cipher.apply_keystream(&mut data); |
| //! assert_eq!(data, [1, 2, 3, 4, 5, 6, 7]); |
| //! ``` |
| |
| #![no_std] |
| #![doc( |
| html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg", |
| html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg", |
| html_root_url = "https://docs.rs/salsa20/0.8.1" |
| )] |
| #![cfg_attr(docsrs, feature(doc_cfg))] |
| #![deny(unsafe_code)] |
| #![warn(missing_docs, rust_2018_idioms, trivial_casts, unused_qualifications)] |
| |
| pub use cipher; |
| |
| mod core; |
| mod rounds; |
| mod salsa; |
| #[cfg(feature = "xsalsa20")] |
| mod xsalsa; |
| |
| pub use crate::salsa::{Key, Nonce, Salsa, Salsa12, Salsa20, Salsa8}; |
| |
| #[cfg(feature = "expose-core")] |
| pub use crate::{ |
| core::Core, |
| rounds::{R12, R20, R8}, |
| }; |
| |
| #[cfg(feature = "hsalsa20")] |
| pub use crate::xsalsa::hsalsa20; |
| |
| #[cfg(feature = "xsalsa20")] |
| pub use crate::xsalsa::{XNonce, XSalsa20}; |
| |
| /// Size of a Salsa20 block in bytes |
| pub const BLOCK_SIZE: usize = 64; |
| |
| /// Size of a Salsa20 key in bytes |
| pub const KEY_SIZE: usize = 32; |
| |
| /// Number of 32-bit words in the Salsa20 state |
| const STATE_WORDS: usize = 16; |
| |
| /// State initialization constant ("expand 32-byte k") |
| const CONSTANTS: [u32; 4] = [0x6170_7865, 0x3320_646e, 0x7962_2d32, 0x6b20_6574]; |