|0.1.2||Mar 12, 2019|
|0.1.1||Feb 17, 2017|
|0.1.0||Feb 16, 2017|
#861 in Cryptography
SPARX is a family of lightweight block ciphers allowing small processors to securely encrypt information for a fraction of the cost a standard algorithm would require.
Due to the use of ARX operations, these block ciphers are inherently more secure against side-channel attacks than an S-Box-based cipher such as AES.
Furthermore, unlike all other ARX-based, which share those advantages, SPARX ciphers are the only ARX-based block ciphers for which bounds on the probability of differential and linear trails can be proved.
To sum up, SPARX has:
- the lightweightness and side-channel resilience of an ARX-based cipher,
- the security argument of an S-Box-based cipher, and
- a flexible structure easing implementation trade-offs.
This crate implements SPARX-64/128 (64 bit block size, 128 bit key) in the
sparx64 module and SPARX-128/128 (128 bit block size, 128 bit key) in the
It doesn't require the Rust standard library.
let key: [u8; KEY_SIZE] = [0x11, 0x00, 0x33, 0x22, 0x55, 0x44, 0x77, 0x66, 0x99, 0x88, 0xbb, 0xaa, 0xdd, 0xcc, 0xff, 0xee]; let mut block: [u8; BLOCK_SIZE] = [0x23, 0x01, 0x67, 0x45, 0xab, 0x89, 0xef, 0xcd]; let ks = key_schedule_encrypt(&key); // key schedule - can be reused with multiple blocks encrypt_block(&mut block, &ks); // ...
decrypt_block() performs the inverse operation:
let ks = key_schedule_decrypt(&key); // key schedule - can be reused with multiple blocks decrypt_block(&mut block, &ks);
This uses SPARX in counter mode as well as a 160-bit nonce in order to encrypt multiple blocks.
The internal counter size for this construction with SPARX-64/128 is 32 bits (no more than 32 GB should be encrypted with the same
(key, nonce) tuple) and 48 bits with SPARX-128/128 (allowing up to 4 PB to be encrypted with the same
(key, nonce) tuple).
The nonce is large enough to be randomly chosen; the probably of a collision to occur will be negligible.
Note that this construction does not add any authentication tags to the message.
let nonce: [u8; NONCE_SIZE] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]; let key: [u8; KEY_SIZE] = [0x11, 0x00, 0x33, 0x22, 0x55, 0x44, 0x77, 0x66, 0x99, 0x88, 0xbb, 0xaa, 0xdd, 0xcc, 0xff, 0xee]; let input = b"The quick brown fox jumps over the lazy dog"; let mut buf = input.to_vec(); encrypt_ctr(&mut buf, &nonce, &key); // ... decrypt_ctr(&mut buf, &nonce, &key);
- Design Strategies for ARX with Provable Bounds: SPARX and LAX (Daniel Dinu, Léo Perrin, Aleksei Udovenko, Vesselin Velichkov, Johann Großschädl, Alex Biryukov).