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#![no_std]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![doc(
html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
html_root_url = "https://docs.rs/rabbit/0.4.1"
)]
#![deny(unsafe_code)]
#![warn(missing_docs, rust_2018_idioms)]
pub use cipher;
use cipher::{
consts::{U1, U16, U8},
crypto_common::InnerUser,
Block, BlockSizeUser, InnerIvInit, IvSizeUser, KeyInit, KeySizeUser, ParBlocksSizeUser,
StreamBackend, StreamCipherCore, StreamCipherCoreWrapper, StreamClosure,
};
#[cfg(feature = "zeroize")]
use cipher::zeroize::{Zeroize, ZeroizeOnDrop};
const KEY_BYTE_LEN: usize = 16;
const IV_BYTE_LEN: usize = 8;
const WORDSIZE: u64 = 1 << 32;
const A: [u32; 8] = [
0x4D34D34D, 0xD34D34D3, 0x34D34D34, 0x4D34D34D, 0xD34D34D3, 0x34D34D34, 0x4D34D34D, 0xD34D34D3,
];
pub type Key = cipher::Key<RabbitCore>;
pub type Iv = cipher::Iv<RabbitCore>;
type BlockSize = U16;
pub type RabbitKeyOnly = StreamCipherCoreWrapper<RabbitKeyOnlyCore>;
pub type Rabbit = StreamCipherCoreWrapper<RabbitCore>;
#[derive(Clone)]
struct State {
x: [u32; 8],
c: [u32; 8],
carry_bit: u8,
}
impl State {
fn setup_key(key: [u8; KEY_BYTE_LEN]) -> Self {
let mut k = [0u16; 8];
k[0] = (key[0x0] as u16) | ((key[0x1] as u16) << 8);
k[1] = (key[0x2] as u16) | ((key[0x3] as u16) << 8);
k[2] = (key[0x4] as u16) | ((key[0x5] as u16) << 8);
k[3] = (key[0x6] as u16) | ((key[0x7] as u16) << 8);
k[4] = (key[0x8] as u16) | ((key[0x9] as u16) << 8);
k[5] = (key[0xA] as u16) | ((key[0xB] as u16) << 8);
k[6] = (key[0xC] as u16) | ((key[0xD] as u16) << 8);
k[7] = (key[0xE] as u16) | ((key[0xF] as u16) << 8);
let mut x = [0u32; 8];
let mut c = [0u32; 8];
for j in 0..8 {
if j % 2 == 0 {
x[j] = ((k[(j + 1) % 8] as u32) << 16) | (k[j] as u32);
c[j] = ((k[(j + 4) % 8] as u32) << 16) | (k[(j + 5) % 8] as u32);
} else {
x[j] = ((k[(j + 5) % 8] as u32) << 16) | (k[(j + 4) % 8] as u32);
c[j] = ((k[j] as u32) << 16) | (k[(j + 1) % 8] as u32);
}
}
let carry_bit = 0;
let mut state = Self { x, c, carry_bit };
for _ in 0..4 {
state.next_state();
}
for j in 0..8 {
state.c[j] ^= state.x[(j + 4) % 8];
}
state
}
fn setup_iv(&mut self, iv: [u8; IV_BYTE_LEN]) {
let mut i = [0_u32; 4];
i[0] = iv[0] as u32 | (iv[1] as u32) << 8 | (iv[2] as u32) << 16 | (iv[3] as u32) << 24;
i[2] = iv[4] as u32 | (iv[5] as u32) << 8 | (iv[6] as u32) << 16 | (iv[7] as u32) << 24;
i[1] = (i[0] >> 16) | (i[2] & 0xFFFF0000);
i[3] = (i[2] << 16) | (i[0] & 0x0000FFFF);
self.c[0] ^= i[0];
self.c[1] ^= i[1];
self.c[2] ^= i[2];
self.c[3] ^= i[3];
self.c[4] ^= i[0];
self.c[5] ^= i[1];
self.c[6] ^= i[2];
self.c[7] ^= i[3];
for _ in 0..4 {
self.next_state();
}
}
fn counter_update(&mut self) {
#[allow(unused_mut, clippy::needless_range_loop)]
for j in 0..8 {
let t = self.c[j] as u64 + A[j] as u64 + self.carry_bit as u64;
self.carry_bit = ((t / WORDSIZE) as u8) & 0b1;
self.c[j] = (t % WORDSIZE) as u32;
}
}
fn next_state(&mut self) {
let mut g = [0u32; 8];
self.counter_update();
#[allow(clippy::needless_range_loop)]
for j in 0..8 {
let u_plus_v = self.x[j] as u64 + self.c[j] as u64;
let square_uv = (u_plus_v % WORDSIZE) * (u_plus_v % WORDSIZE);
g[j] = (square_uv ^ (square_uv >> 32)) as u32;
}
self.x[0] = g[0]
.wrapping_add(g[7].rotate_left(16))
.wrapping_add(g[6].rotate_left(16));
self.x[1] = g[1].wrapping_add(g[0].rotate_left(8)).wrapping_add(g[7]);
self.x[2] = g[2]
.wrapping_add(g[1].rotate_left(16))
.wrapping_add(g[0].rotate_left(16));
self.x[3] = g[3].wrapping_add(g[2].rotate_left(8)).wrapping_add(g[1]);
self.x[4] = g[4]
.wrapping_add(g[3].rotate_left(16))
.wrapping_add(g[2].rotate_left(16));
self.x[5] = g[5].wrapping_add(g[4].rotate_left(8)).wrapping_add(g[3]);
self.x[6] = g[6]
.wrapping_add(g[5].rotate_left(16))
.wrapping_add(g[4].rotate_left(16));
self.x[7] = g[7].wrapping_add(g[6].rotate_left(8)).wrapping_add(g[5]);
}
fn extract(&self) -> [u8; 16] {
let mut s = [0u8; 16];
let mut tmp = [0_u16; 8];
tmp[0] = ((self.x[0]) ^ (self.x[5] >> 16)) as u16;
tmp[1] = ((self.x[0] >> 16) ^ (self.x[3])) as u16;
tmp[2] = ((self.x[2]) ^ (self.x[7] >> 16)) as u16;
tmp[3] = ((self.x[2] >> 16) ^ (self.x[5])) as u16;
tmp[4] = ((self.x[4]) ^ (self.x[1] >> 16)) as u16;
tmp[5] = ((self.x[4] >> 16) ^ (self.x[7])) as u16;
tmp[6] = ((self.x[6]) ^ (self.x[3] >> 16)) as u16;
tmp[7] = ((self.x[6] >> 16) ^ (self.x[1])) as u16;
s[0x0] = tmp[0] as u8;
s[0x1] = (tmp[0] >> 8) as u8;
s[0x2] = tmp[1] as u8;
s[0x3] = (tmp[1] >> 8) as u8;
s[0x4] = tmp[2] as u8;
s[0x5] = (tmp[2] >> 8) as u8;
s[0x6] = tmp[3] as u8;
s[0x7] = (tmp[3] >> 8) as u8;
s[0x8] = tmp[4] as u8;
s[0x9] = (tmp[4] >> 8) as u8;
s[0xA] = tmp[5] as u8;
s[0xB] = (tmp[5] >> 8) as u8;
s[0xC] = tmp[6] as u8;
s[0xD] = (tmp[6] >> 8) as u8;
s[0xE] = tmp[7] as u8;
s[0xF] = (tmp[7] >> 8) as u8;
s
}
fn next_block(&mut self) -> [u8; 16] {
self.next_state();
self.extract()
}
}
#[cfg(feature = "zeroize")]
impl core::ops::Drop for State {
fn drop(&mut self) {
self.x.zeroize();
self.c.zeroize();
self.carry_bit.zeroize();
}
}
#[derive(Clone)]
pub struct RabbitKeyOnlyCore {
state: State,
}
impl KeySizeUser for RabbitKeyOnlyCore {
type KeySize = U16;
}
impl KeyInit for RabbitKeyOnlyCore {
fn new(key: &Key) -> Self {
Self {
state: State::setup_key((*key).into()),
}
}
}
impl BlockSizeUser for RabbitKeyOnlyCore {
type BlockSize = BlockSize;
}
impl StreamCipherCore for RabbitKeyOnlyCore {
#[inline(always)]
fn remaining_blocks(&self) -> Option<usize> {
None
}
fn process_with_backend(&mut self, f: impl StreamClosure<BlockSize = Self::BlockSize>) {
f.call(&mut Backend(&mut self.state));
}
}
#[cfg(feature = "zeroize")]
#[cfg_attr(docsrs, doc(cfg(feature = "zeroize")))]
impl ZeroizeOnDrop for RabbitKeyOnlyCore {}
#[derive(Clone)]
pub struct RabbitCore {
state: State,
}
impl InnerUser for RabbitCore {
type Inner = RabbitKeyOnlyCore;
}
impl IvSizeUser for RabbitCore {
type IvSize = U8;
}
impl InnerIvInit for RabbitCore {
fn inner_iv_init(inner: RabbitKeyOnlyCore, iv: &Iv) -> Self {
let mut state = inner.state;
state.setup_iv((*iv).into());
Self { state }
}
}
impl BlockSizeUser for RabbitCore {
type BlockSize = BlockSize;
}
impl StreamCipherCore for RabbitCore {
#[inline(always)]
fn remaining_blocks(&self) -> Option<usize> {
None
}
fn process_with_backend(&mut self, f: impl StreamClosure<BlockSize = Self::BlockSize>) {
f.call(&mut Backend(&mut self.state));
}
}
struct Backend<'a>(&'a mut State);
impl<'a> BlockSizeUser for Backend<'a> {
type BlockSize = BlockSize;
}
impl<'a> ParBlocksSizeUser for Backend<'a> {
type ParBlocksSize = U1;
}
impl<'a> StreamBackend for Backend<'a> {
#[inline(always)]
fn gen_ks_block(&mut self, block: &mut Block<Self>) {
block.copy_from_slice(&self.0.next_block());
}
}
#[cfg(feature = "zeroize")]
#[cfg_attr(docsrs, doc(cfg(feature = "zeroize")))]
impl ZeroizeOnDrop for RabbitCore {}