Collection of stream ciphers written in pure Rust.

Crates in this repository do not ensure ciphertexts are authentic (i.e. by using a MAC to verify ciphertext integrity), which can lead to serious vulnerabilities if used incorrectly!

Aside from the chacha20 crate, no crates in this repository have yet received any formal cryptographic and security reviews/audits.

USE AT YOUR OWN RISK!

Name	Crate name	Crates.io	Docs	MSRV	Security
ChaCha	chacha20				💚
HC-256	hc-256				💛
Rabbit	rabbit				💛
RC4	rc4				💔
Salsa20	salsa20				💚

The following describes the security level ratings associated with each hash function (i.e. algorithms, not the specific implementation):

MSRV bump is considered a breaking change and will be performed only with a minor version bump.

Crates functionality is expressed in terms of traits defined in the cipher crate.

Let's use ChaCha20 to demonstrate usage of synchronous stream cipher:

use chacha20::ChaCha20;
// Import relevant traits
use chacha20::cipher::{KeyIvInit, StreamCipher, StreamCipherSeek};
use hex_literal::hex;

let key = [0x42; 32];
let nonce = [0x24; 12];
let plaintext = hex!("00010203 04050607 08090a0b 0c0d0e0f");
let ciphertext = hex!("e405626e 4f1236b3 670ee428 332ea20e");

// Key and IV must be references to the `GenericArray` type.
// Here we use the `Into` trait to convert arrays into it.
let mut cipher = ChaCha20::new(&key.into(), &nonce.into());

let mut buffer = plaintext.clone();

// apply keystream (encrypt)
cipher.apply_keystream(&mut buffer);
assert_eq!(buffer, ciphertext);

let ciphertext = buffer.clone();

// ChaCha ciphers support seeking
cipher.seek(0u32);

// decrypt ciphertext by applying keystream again
cipher.apply_keystream(&mut buffer);
assert_eq!(buffer, plaintext);

// stream ciphers can be used with streaming messages
cipher.seek(0u32);
for chunk in buffer.chunks_mut(3) {
    cipher.apply_keystream(chunk);
}
assert_eq!(buffer, ciphertext);

All crates licensed under either of

• Apache License, Version 2.0
• MIT license

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.