parity.rs

fn parity(xs: &[u8]) -> u64 {
    let mut ret = 0u64;

    for (i, _) in xs.iter().enumerate() {
        let mut acc = 0;
        for j in i..i + 8 {
            let x = xs[j % xs.len()];
            acc ^= (x >> (7 - ((i + 1) % 8))) & 0b1;
        }
        ret |= (acc as u64) << (xs.len() - (i+1));
    }

    ret
}

fn main() {
    println!(
        "0x{:X}",
        parity(&"CRYPT0GR4PHY".bytes().collect::<Vec<_>>())
    );
    println!(
        "0x{:X}",
        parity(&"BSYPT0GR4PHY".bytes().collect::<Vec<_>>())
    );
}