10 releases
0.3.3 | Oct 24, 2021 |
---|---|
0.3.1 | May 12, 2021 |
0.3.0 | Nov 2, 2020 |
0.2.4 | May 16, 2020 |
0.1.0 | Feb 3, 2019 |
#228 in Cryptography
196,610 downloads per month
Used in 153 crates
(6 directly)
145KB
4K
SLoC
The ChaCha family of stream ciphers
Features
- pure Rust implementation
- supports the RustCrypto API
- builds on stable Rust
- portable
- fast: within 15% of throughput of a hand-optimized ASM SIMD implementation (floodberry/chacha-opt) on my machine (a Xeon X5650, using ppv-lite86)
- no-std compatible (std required only for runtime algorithm selection)
Supported Variants
ChaCha20: used in chacha20-poly1305 in TLS, OpenSSH; arc4random in the BSDs, Linux /dev/urandom since 4.8.
Ietf: IETF RFC 7539. Longer nonce, short block counter.
XChaCha20: constructed analogously to XSalsa20; a mixing step during initialization allows using a long nonce and along with a full-sized block counter.
ChaCha12, ChaCha8: faster; lower security margin of safety.
lib.rs
:
Pure Rust ChaCha with SIMD optimizations.
Stream-cipher usage:
#[cfg(features = "std")]
fn demo() {
extern crate c2_chacha;
use c2_chacha::stream_cipher::{NewStreamCipher, SyncStreamCipher, SyncStreamCipherSeek};
use c2_chacha::{ChaCha20, ChaCha12};
let key = b"very secret key-the most secret.";
let iv = b"my nonce";
let plaintext = b"The quick brown fox jumps over the lazy dog.";
let mut buffer = plaintext.to_vec();
// create cipher instance
let mut cipher = ChaCha20::new_var(key, iv).unwrap();
// apply keystream (encrypt)
cipher.apply_keystream(&mut buffer);
// and decrypt it back
cipher.seek(0);
cipher.apply_keystream(&mut buffer);
// stream ciphers can be used with streaming messages
let mut cipher = ChaCha12::new_var(key, iv).unwrap();
for chunk in buffer.chunks_mut(3) {
cipher.apply_keystream(chunk);
}
}
Dependencies
~1–1.6MB
~28K SLoC