rind 0.1.0

Pure-Rust cryptography for MoQ, forked from graviola
Documentation 
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// SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT-0

use crate::low::AesKey;

/// XORs eight blocks of AES-CTR keystream into `inout`.
///
/// The counter blocks are `nonce` followed by the big-endian `counter`,
/// `counter + 1`, ... `counter + 7`, wrapping within 32 bits.
pub(crate) fn apply_8(key: &AesKey, nonce: &[u8; 12], counter: u32, inout: &mut [u8; 128]) {
    if let AesKey::Hw(key) = key {
        let mut ivec = [0u8; 16];
        ivec[..12].copy_from_slice(nonce);
        ivec[12..].copy_from_slice(&counter.to_be_bytes());
        return key.ctr32(&ivec, inout.as_chunks_mut::<16>().0);
    }

    let mut keystream = [0u8; 16];
    for (i, block) in (0u32..).zip(inout.as_chunks_mut::<16>().0) {
        keystream[..12].copy_from_slice(nonce);
        keystream[12..].copy_from_slice(&counter.wrapping_add(i).to_be_bytes());
        key.encrypt_block(&mut keystream);
        for (b, k) in block.iter_mut().zip(keystream) {
            *b ^= k;
        }
    }
}