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use crate::{sign_message, verify_message};
use anyhow::anyhow;
use secp256k1::{PublicKey, SecretKey};
use std::convert::TryInto;
pub struct Controller(SecretKey, PublicKey, u64);
const SIG_LEN: usize = 65;
impl Controller {
pub fn new(sk: SecretKey, pk: PublicKey, nonce: u64) -> Self {
Self(sk, pk, nonce)
}
pub fn nonce(&self) -> u64 {
self.2
}
pub fn pubkey(&self) -> PublicKey {
self.1
}
pub fn build_msg(&mut self, d: &[u8]) -> anyhow::Result<Vec<u8>> {
self.2 = self.2 + 1;
Ok(build_msg(d, &self.0, self.2)?)
}
pub fn build_msg_with_nonce(&mut self, d: &[u8], nonce: u64) -> anyhow::Result<Vec<u8>> {
Ok(build_msg(d, &self.0, nonce)?)
}
pub fn parse_msg(&mut self, input: &[u8]) -> anyhow::Result<Vec<u8>> {
let res = parse_msg(input, &self.1, self.2)?;
self.2 = self.2 + 1;
Ok(res)
}
pub fn parse_msg_with_nonce(&mut self, input: &[u8], nonce: u64) -> anyhow::Result<Vec<u8>> {
let res = parse_msg(input, &self.1, nonce)?;
Ok(res)
}
}
pub fn build_msg(input: &[u8], sk: &SecretKey, nonce: u64) -> anyhow::Result<Vec<u8>> {
let mut d = input.to_vec();
d.extend_from_slice(&nonce.to_be_bytes());
let sig = sign_message(&d, sk)?;
d.extend_from_slice(&sig);
Ok(d)
}
pub fn parse_msg(input: &[u8], pk: &PublicKey, last_nonce: u64) -> anyhow::Result<Vec<u8>> {
let (msg, nonce) = parse_msg_no_nonce(input, pk)?;
if nonce <= last_nonce {
println!("nonce {} last_mnone {}", nonce, last_nonce);
return Err(anyhow!("bad nonce"));
}
Ok(msg.to_vec())
}
pub fn parse_msg_no_nonce(input: &[u8], pk: &PublicKey) -> anyhow::Result<(Vec<u8>, u64)> {
if input.len() < SIG_LEN + 8 + 1 {
return Err(anyhow!("msg too short"));
}
let msg_sig = input.split_at(input.len() - SIG_LEN);
let sig: [u8; SIG_LEN] = msg_sig.1.try_into()?;
let msg_nonce = msg_sig.0.split_at(msg_sig.0.len() - 8);
let nonce_bytes: [u8; 8] = msg_nonce.1.try_into()?;
let nonce = u64::from_be_bytes(nonce_bytes);
let msg = msg_nonce.0;
verify_message(msg_sig.0, &sig, pk)?;
Ok((msg.to_vec(), nonce))
}
#[cfg(test)]
mod tests {
use crate::nonce::*;
use secp256k1::{PublicKey, Secp256k1, SecretKey};
fn secret_key() -> SecretKey {
SecretKey::from_slice(&[0xcd; 32]).expect("32 bytes, within curve order")
}
#[test]
fn test_nonce() {
let secp = Secp256k1::new();
let sk = secret_key();
let public_key = PublicKey::from_secret_key(&secp, &sk);
let input = vec![1, 2, 3];
let mut cont = Controller::new(sk, public_key, 0);
let msg = cont.build_msg(&input).expect("couldnt sign");
let parsed = cont.parse_msg_with_nonce(&msg, 0).expect("couldnt verify");
assert_eq!(input, parsed, "unequal");
}
}