If you are using a stable Rust build:
[dependencies]
chacha = "0.1.0"
If you need maximum performance, using a nightly Rust build:
[dependencies.chacha]
version = "0.1.0"
features = ["nightly"]
extern crate chacha;
use chacha::{ChaCha, KeyStream};
fn main() {
let secret_key = [
0x29, 0xfa, 0x35, 0x60, 0x88, 0x45, 0xc6, 0xf9,
0xd8, 0xfe, 0x65, 0xe3, 0x22, 0x0e, 0x5b, 0x05,
0x03, 0x4a, 0xa0, 0x9f, 0x9e, 0x27, 0xad, 0x0f,
0x6c, 0x90, 0xa5, 0x73, 0xa8, 0x10, 0xe4, 0x94,
];
let nonce = [0u8; 8];
let mut stream = ChaCha::new_chacha20(&secret_key, &nonce);
let mut buffer = *b"abcdef";
println!("Plaintext = {:?}", buffer);
stream.xor_read(&mut buffer[..]).expect("hit end of stream far too soon");
println!("Ciphertext = {:?}", buffer);
}