//! Common cryptographic traits.
#![no_std]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![doc(
html_logo_url = "
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html_favicon_url = "
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)]
#![forbid(unsafe_code)]
#![warn(missing_docs, rust_2018_idioms)]
#[cfg(feature = "std")]
extern crate std;
#[cfg(feature = "rand_core")]
pub use rand_core;
pub use generic_array;
pub use generic_array::typenum;
use core::fmt;
use generic_array::{typenum::Unsigned, ArrayLength, GenericArray};
#[cfg(feature = "rand_core")]
use rand_core::{CryptoRng, RngCore};
/// Block on which [`BlockSizeUser`] implementors operate.
pub type Block<B> = GenericArray<u8, <B as BlockSizeUser>::BlockSize>;
/// Parallel blocks on which [`ParBlocksSizeUser`] implementors operate.
pub type ParBlocks<T> = GenericArray<Block<T>, <T as ParBlocksSizeUser>::ParBlocksSize>;
/// Output array of [`OutputSizeUser`] implementors.
pub type Output<T> = GenericArray<u8, <T as OutputSizeUser>::OutputSize>;
/// Key used by [`KeySizeUser`] implementors.
pub type Key<B> = GenericArray<u8, <B as KeySizeUser>::KeySize>;
/// Initialization vector (nonce) used by [`IvSizeUser`] implementors.
pub type Iv<B> = GenericArray<u8, <B as IvSizeUser>::IvSize>;
/// Types which process data in blocks.
pub trait BlockSizeUser {
/// Size of the block in bytes.
type BlockSize: ArrayLength<u8> + 'static;
/// Return block size in bytes.
fn block_size() -> usize {
Self::BlockSize::USIZE
}
}
impl<T: BlockSizeUser> BlockSizeUser for &T {
type BlockSize = T::BlockSize;
}
impl<T: BlockSizeUser> BlockSizeUser for &mut T {
type BlockSize = T::BlockSize;
}
/// Types which can process blocks in parallel.
pub trait ParBlocksSizeUser: BlockSizeUser {
/// Number of blocks which can be processed in parallel.
type ParBlocksSize: ArrayLength<Block<Self>>;
}
/// Types which return data with the given size.
pub trait OutputSizeUser {
/// Size of the output in bytes.
type OutputSize: ArrayLength<u8> + 'static;
/// Return output size in bytes.
fn output_size() -> usize {
Self::OutputSize::USIZE
}
}
/// Types which use key for initialization.
///
/// Generally it's used indirectly via [`KeyInit`] or [`KeyIvInit`].
pub trait KeySizeUser {
/// Key size in bytes.
type KeySize: ArrayLength<u8> + 'static;
/// Return key size in bytes.
fn key_size() -> usize {
Self::KeySize::USIZE
}
}
/// Types which use initialization vector (nonce) for initialization.
///
/// Generally it's used indirectly via [`KeyIvInit`] or [`InnerIvInit`].
pub trait IvSizeUser {
/// Initialization vector size in bytes.
type IvSize: ArrayLength<u8> + 'static;
/// Return IV size in bytes.
fn iv_size() -> usize {
Self::IvSize::USIZE
}
}
/// Types which use another type for initialization.
///
/// Generally it's used indirectly via [`InnerInit`] or [`InnerIvInit`].
pub trait InnerUser {
/// Inner type.
type Inner;
}
/// Resettable types.
pub trait Reset {
/// Reset state to its initial value.
fn reset(&mut self);
}
/// Trait which stores algorithm name constant, used in `Debug` implementations.
pub trait AlgorithmName {
/// Write algorithm name into `f`.
fn write_alg_name(f: &mut fmt::Formatter<'_>) -> fmt::Result;
}
/// Types which can be initialized from key.
pub trait KeyInit: KeySizeUser + Sized {
/// Create new value from fixed size key.
fn new(key: &Key<Self>) -> Self;
/// Create new value from variable size key.
fn new_from_slice(key: &[u8]) -> Result<Self, InvalidLength> {
if key.len() != Self::KeySize::to_usize() {
Err(InvalidLength)
} else {
Ok(Self::new(Key::<Self>::from_slice(key)))
}
}
/// Generate random key using the provided [`CryptoRng`].
#[cfg(feature = "rand_core")]
#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
#[inline]
fn generate_key(mut rng: impl CryptoRng + RngCore) -> Key<Self> {
let mut key = Key::<Self>::default();
rng.fill_bytes(&mut key);
key
}
}
/// Types which can be initialized from key and initialization vector (nonce).
pub trait KeyIvInit: KeySizeUser + IvSizeUser + Sized {
/// Create new value from fixed length key and nonce.
fn new(key: &Key<Self>, iv: &Iv<Self>) -> Self;
/// Create new value from variable length key and nonce.
#[inline]
fn new_from_slices(key: &[u8], iv: &[u8]) -> Result<Self, InvalidLength> {
let key_len = Self::KeySize::USIZE;
let iv_len = Self::IvSize::USIZE;
if key.len() != key_len || iv.len() != iv_len {
Err(InvalidLength)
} else {
Ok(Self::new(
Key::<Self>::from_slice(key),
Iv::<Self>::from_slice(iv),
))
}
}
/// Generate random key using the provided [`CryptoRng`].
#[cfg(feature = "rand_core")]
#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
#[inline]
fn generate_key(mut rng: impl CryptoRng + RngCore) -> Key<Self> {
let mut key = Key::<Self>::default();
rng.fill_bytes(&mut key);
key
}
/// Generate random IV using the provided [`CryptoRng`].
#[cfg(feature = "rand_core")]
#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
#[inline]
fn generate_iv(mut rng: impl CryptoRng + RngCore) -> Iv<Self> {
let mut iv = Iv::<Self>::default();
rng.fill_bytes(&mut iv);
iv
}
/// Generate random key and nonce using the provided [`CryptoRng`].
#[cfg(feature = "rand_core")]
#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
#[inline]
fn generate_key_iv(mut rng: impl CryptoRng + RngCore) -> (Key<Self>, Iv<Self>) {
(Self::generate_key(&mut rng), Self::generate_iv(&mut rng))
}
}
/// Types which can be initialized from another type (usually block ciphers).
///
/// Usually used for initializing types from block ciphers.
pub trait InnerInit: InnerUser + Sized {
/// Initialize value from the `inner`.
fn inner_init(inner: Self::Inner) -> Self;
}
/// Types which can be initialized from another type and additional initialization
/// vector/nonce.
///
/// Usually used for initializing types from block ciphers.
pub trait InnerIvInit: InnerUser + IvSizeUser + Sized {
/// Initialize value using `inner` and `iv` array.
fn inner_iv_init(inner: Self::Inner, iv: &Iv<Self>) -> Self;
/// Initialize value using `inner` and `iv` slice.
fn inner_iv_slice_init(inner: Self::Inner, iv: &[u8]) -> Result<Self, InvalidLength> {
if iv.len() != Self::IvSize::to_usize() {
Err(InvalidLength)
} else {
Ok(Self::inner_iv_init(inner, Iv::<Self>::from_slice(iv)))
}
}
/// Generate random IV using the provided [`CryptoRng`].
#[cfg(feature = "rand_core")]
#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
#[inline]
fn generate_iv(mut rng: impl CryptoRng + RngCore) -> Iv<Self> {
let mut iv = Iv::<Self>::default();
rng.fill_bytes(&mut iv);
iv
}
}
impl<T> KeySizeUser for T
where
T: InnerUser,
T::Inner: KeySizeUser,
{
type KeySize = <T::Inner as KeySizeUser>::KeySize;
}
impl<T> KeyIvInit for T
where
T: InnerIvInit,
T::Inner: KeyInit,
{
#[inline]
fn new(key: &Key<Self>, iv: &Iv<Self>) -> Self {
Self::inner_iv_init(T::Inner::new(key), iv)
}
#[inline]
fn new_from_slices(key: &[u8], iv: &[u8]) -> Result<Self, InvalidLength> {
T::Inner::new_from_slice(key).and_then(|i| T::inner_iv_slice_init(i, iv))
}
}
impl<T> KeyInit for T
where
T: InnerInit,
T::Inner: KeyInit,
{
#[inline]
fn new(key: &Key<Self>) -> Self {
Self::inner_init(T::Inner::new(key))
}
#[inline]
fn new_from_slice(key: &[u8]) -> Result<Self, InvalidLength> {
T::Inner::new_from_slice(key)
.map_err(|_| InvalidLength)
.map(Self::inner_init)
}
}
// Unfortunately this blanket impl is impossible without mutually
// exclusive traits, see:
https://github.com/rust-lang/rfcs/issues/1053
// or at the very least without:
https://github.com/rust-lang/rust/issues/20400
/*
impl<T> KeyIvInit for T
where
T: InnerInit,
T::Inner: KeyIvInit,
{
#[inline]
fn new(key: &Key<Self>, iv: &Iv<Self>) -> Self {
Self::inner_init(T::Inner::new(key, iv))
}
#[inline]
fn new_from_slices(key: &[u8], iv: &[u8]) -> Result<Self, InvalidLength> {
T::Inner::new_from_slice(key)
.map_err(|_| InvalidLength)
.map(Self::inner_init)
}
}
*/
/// The error type returned when key and/or IV used in the [`KeyInit`],
/// [`KeyIvInit`], and [`InnerIvInit`] slice-based methods had
/// an invalid length.
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub struct InvalidLength;
impl fmt::Display for InvalidLength {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
f.write_str("Invalid Length")
}
}
#[cfg(feature = "std")]
impl std::error::Error for InvalidLength {}
