kyber_rs/cipher/
stream.rs

1use thiserror::Error;
2
3use crate::xof::blake3::XOFError;
4
5/// A [`Stream`] represents a stream cipher.
6pub trait Stream {
7    /// [`xor_key_stream()`] XORs each byte in the given slice with a byte from the
8    /// cipher's key stream; `dst` and `src` must overlap entirely or not at all.
9    ///
10    /// If `dst.len() < src.len()`, [`xor_key_stream()`] should panic. It is acceptable
11    /// to pass a `dst` bigger than `src`, and in that case, [`xor_key_stream()`] will
12    /// only update `dst[..src.len()]` and will not touch the rest of `dst`.
13    ///
14    /// Multiple calls to [`xor_key_stream()`] behave as if the concatenation of
15    /// the `src` buffers was passed in a single run. That is, [`Stream`]
16    /// maintains state and does not reset at each [`xor_key_stream()`] call.
17    fn xor_key_stream(&mut self, dst: &mut [u8], src: &[u8]) -> Result<(), StreamError>;
18}
19
20impl<S: Stream + ?Sized> Stream for Box<S> {
21    fn xor_key_stream(&mut self, dst: &mut [u8], src: &[u8]) -> Result<(), StreamError> {
22        self.as_mut().xor_key_stream(dst, src)
23    }
24}
25
26#[derive(Error, Debug)]
27pub enum StreamError {
28    #[error("io error")]
29    IoError(#[from] std::io::Error),
30    #[error("XOF error")]
31    XOFError(#[from] XOFError),
32    #[error("mismatched buffer lengths")]
33    WrongBufferLengths,
34    #[error("all readers failed")]
35    ReadersFailure,
36}
kyber_rs/cipher/stream.rs

kyber_rs/cipher/
stream.rs
