Struct Field

Source

pub struct Field {
    pub v: u64,
}

Expand description

Simple finite field arithmetic modulo a prime p (u64). Uses u128 intermediates to avoid overflow on multiplication.

Fields§

§v: u64

Implementations§

Source §

impl Field

Source

pub const MOD: u64 = 65_537u64

Set the prime modulus here. For prototype/testing you can change it.

Source

pub fn new(x: u128) -> Self

Create element with reduction

Examples found in repository ?

examples/channel.rs (line 13)

3fn main() {
4    // Example coefficients for recurrence: x^3 + 2x^2 + 3x + 4
5    let coeffs = vec![4, 3, 2];
6    let cm = CompanionMatrix::from_coeffs(&coeffs);
7
8    // Example polynomial for T: g(x) = 1 + 2x
9    let g_coeffs = vec![1, 2];
10    let t = StreamGenerator::build_t_from_poly(&cm, &g_coeffs);
11
12    // Initial state vector
13    let state = vec![Field::new(1), Field::new(0), Field::new(0)];
14
15    let mut sg = StreamGenerator::new(cm, t, state);
16
17    // Generate and print first 10 outputs
18    for _ in 0..10 {
19        let output = sg.step();
20        println!("{:?}", output);
21    }
22}

Source

pub fn zero() -> Self

Source

pub fn one() -> Self

Examples found in repository ?

examples/net_receiver.rs (line 9)

5fn handle_client(mut socket: TcpStream) -> io::Result<()> {
6    let coeffs = vec![1, 2, 3];
7    let companion = CompanionMatrix::from_coeffs(&coeffs);
8    let t = StreamGenerator::build_t_from_poly(&companion, &coeffs);
9    let state = vec![Field::one(); companion.k];
10    let mut sg = StreamGenerator::new(companion, t, state);
11
12    let mut buf = [0u8; 1024];
13    let stdout = io::stdout();
14    let mut out = stdout.lock();
15
16    loop {
17        let n = socket.read(&mut buf)?;
18        if n == 0 { break; }
19
20        for &b in &buf[..n] {
21            let _mask = sg.step();
22            let decoded = b.wrapping_sub((_mask.v & 0xFF) as u8);
23            write!(out, "{}", decoded as char)?;
24        }
25        out.flush()?;
26    }
27
28    Ok(())
29}

More examples

Hide additional examples

examples/net_sender.rs (line 14)

6fn main() -> io::Result<()> {
7    // Connect to receiver
8    let mut stream = TcpStream::connect("127.0.0.1:4000")?;
9
10    // Example polynomial coefficients and state
11    let coeffs = vec![1, 2, 3];
12    let companion = CompanionMatrix::from_coeffs(&coeffs);
13    let t = StreamGenerator::build_t_from_poly(&companion, &coeffs);
14    let state = vec![Field::one(); companion.k];
15    let mut sg = StreamGenerator::new(companion, t, state);
16
17    // Read plain data from stdin
18    let mut input = Vec::new();
19    io::stdin().read_to_end(&mut input)?;
20
21    // Encode and send
22    for b in input {
23        let _mask = sg.step();
24        // very simple “encryption”: just add the mask
25        let encoded = b.wrapping_add((_mask.v & 0xFF) as u8);
26        stream.write_all(&[encoded])?;
27    }
28
29    Ok(())
30}