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use super::curve::WeierstrassCurve;
#[cfg(feature = "encoding")]
use crate::encoding::Decode;
#[cfg(all(feature = "alloc", feature = "encoding"))]
use crate::encoding::Encode;
#[cfg(all(feature = "alloc", feature = "encoding"))]
use alloc::vec::Vec;
use generic_array::{typenum::Unsigned, GenericArray};
#[cfg(feature = "getrandom")]
use getrandom::getrandom;
#[cfg(feature = "encoding")]
use subtle_encoding::Encoding;
use zeroize::Zeroize;
pub struct SecretKey<C: WeierstrassCurve> {
bytes: GenericArray<u8, C::ScalarSize>,
}
impl<C> SecretKey<C>
where
C: WeierstrassCurve,
{
pub fn new<B>(into_bytes: B) -> Self
where
B: Into<GenericArray<u8, C::ScalarSize>>,
{
Self {
bytes: into_bytes.into(),
}
}
pub fn from_bytes<B: AsRef<[u8]>>(bytes: B) -> Option<Self> {
let slice = bytes.as_ref();
let length = slice.len();
if length == C::ScalarSize::to_usize() {
Some(Self::new(GenericArray::clone_from_slice(slice)))
} else {
None
}
}
#[cfg(feature = "getrandom")]
pub fn generate() -> Self {
let mut bytes = GenericArray::default();
getrandom(bytes.as_mut_slice()).expect("RNG failure!");
Self { bytes }
}
pub fn as_secret_slice(&self) -> &[u8] {
self.bytes.as_ref()
}
}
impl<C: WeierstrassCurve> Clone for SecretKey<C> {
fn clone(&self) -> Self {
Self::new(self.bytes.clone())
}
}
#[cfg(feature = "encoding")]
impl<C> Decode for SecretKey<C>
where
C: WeierstrassCurve,
{
fn decode<E: Encoding>(
encoded_key: &[u8],
encoding: &E,
) -> Result<Self, crate::encoding::Error> {
let mut bytes = GenericArray::default();
let decoded_len = encoding.decode_to_slice(encoded_key, &mut bytes)?;
if decoded_len == C::ScalarSize::to_usize() {
Ok(Self { bytes })
} else {
Err(crate::encoding::error::ErrorKind::Decode.into())
}
}
}
#[cfg(all(feature = "encoding", feature = "alloc"))]
impl<C> Encode for SecretKey<C>
where
C: WeierstrassCurve,
{
fn encode<E: Encoding>(&self, encoding: &E) -> Vec<u8> {
encoding.encode(self.as_secret_slice())
}
}
impl<C> Drop for SecretKey<C>
where
C: WeierstrassCurve,
{
fn drop(&mut self) {
self.bytes.as_mut().zeroize();
}
}