Crate salsa20

The Salsa20 stream cipher.

Cipher functionality is accessed using traits from re-exported stream-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:

Legend:

• ⊞ add
• ‹‹‹ rotate
• ⊕ xor

Usage

use salsa20::Salsa20;
use salsa20::stream_cipher::generic_array::GenericArray;
use salsa20::stream_cipher::{NewStreamCipher, SyncStreamCipher, SyncStreamCipherSeek};

let mut data = [1, 2, 3, 4, 5, 6, 7];

let key = GenericArray::from_slice(b"an example very very secret key.");
let nonce = GenericArray::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]);

Re-exports

pub use stream_cipher;

Structs

Salsa	The Salsa20 family of stream ciphers (implemented generically over a number of rounds).
XSalsa20	feature="xsalsa20" XSalsa20 is a Salsa20 variant with an extended 192-bit (24-byte) nonce.

Constants

BLOCK_SIZE	Size of a Salsa20 block in bytes
KEY_SIZE	Size of a Salsa20 key in bytes

Functions

hsalsa20

feature="hsalsa20" The HSalsa20 function defined in the paper "Extending the Salsa20 nonce"

Type Definitions

Key	Key type.
Nonce	Nonce type
Salsa8	Salsa20/8 stream cipher (reduced-round variant of Salsa20 with 8 rounds, not recommended)
Salsa12	Salsa20/12 stream cipher (reduced-round variant of Salsa20 with 12 rounds, not recommended)
Salsa20	Salsa20/20 stream cipher (20 rounds; recommended)
XNonce	feature="xsalsa20" EXtended Salsa20 nonce (192-bit/24-byte)