kyber-rs 0.1.0-alpha.9

A toolbox of advanced cryptographic primitives for Rust
Documentation 
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use thiserror::Error;

use crate::xof::blake3::XOFError;

/// A [`Stream`] represents a stream cipher.
pub trait Stream {
    /// [`xor_key_stream()`] XORs each byte in the given slice with a byte from the
    /// cipher's key stream; `dst` and `src` must overlap entirely or not at all.
    ///
    /// If `dst.len() < src.len()`, [`xor_key_stream()`] should panic. It is acceptable
    /// to pass a `dst` bigger than `src`, and in that case, [`xor_key_stream()`] will
    /// only update `dst[..src.len()]` and will not touch the rest of `dst`.
    ///
    /// Multiple calls to [`xor_key_stream()`] behave as if the concatenation of
    /// the `src` buffers was passed in a single run. That is, [`Stream`]
    /// maintains state and does not reset at each [`xor_key_stream()`] call.
    fn xor_key_stream(&mut self, dst: &mut [u8], src: &[u8]) -> Result<(), StreamError>;
}

impl<S: Stream + ?Sized> Stream for Box<S> {
    fn xor_key_stream(&mut self, dst: &mut [u8], src: &[u8]) -> Result<(), StreamError> {
        self.as_mut().xor_key_stream(dst, src)
    }
}

#[derive(Error, Debug)]
pub enum StreamError {
    #[error("io error")]
    IoError(#[from] std::io::Error),
    #[error("XOF error")]
    XOFError(#[from] XOFError),
    #[error("mismatched buffer lengths")]
    WrongBufferLengths,
    #[error("all readers failed")]
    ReadersFailure,
}