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use generic_array::GenericArray;
use generic_array::typenum::{U32, U64};
use ring::signature::Ed25519KeyPair;
pub type Sha256Hash = GenericArray<u8, U32>;
pub type PublicKey = GenericArray<u8, U32>;
pub type Signature = GenericArray<u8, U64>;
#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
pub struct Entry {
pub num_hashes: u64,
pub end_hash: Sha256Hash,
pub event: Event,
}
#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
pub enum Event {
Tick,
Discovery {
data: Sha256Hash,
},
Claim {
key: PublicKey,
data: Sha256Hash,
sig: Signature,
},
}
impl Entry {
pub fn new_tick(num_hashes: u64, end_hash: &Sha256Hash) -> Self {
Entry {
num_hashes,
end_hash: *end_hash,
event: Event::Tick,
}
}
pub fn verify(self: &Self, start_hash: &Sha256Hash) -> bool {
if let Event::Claim { key, data, sig } = self.event {
if !verify_signature(&key, &data, &sig) {
return false;
}
}
self.end_hash == next_hash(start_hash, self.num_hashes, &self.event)
}
}
pub fn sign_hash(data: &Sha256Hash, key_pair: &Ed25519KeyPair) -> Event {
let sig = key_pair.sign(data);
let peer_public_key_bytes = key_pair.public_key_bytes();
let sig_bytes = sig.as_ref();
Event::Claim {
key: GenericArray::clone_from_slice(peer_public_key_bytes),
data: GenericArray::clone_from_slice(data),
sig: GenericArray::clone_from_slice(sig_bytes),
}
}
pub fn hash(val: &[u8]) -> Sha256Hash {
use sha2::{Digest, Sha256};
let mut hasher = Sha256::default();
hasher.input(val);
hasher.result()
}
pub fn extend_and_hash(end_hash: &Sha256Hash, ty: u8, val: &[u8]) -> Sha256Hash {
let mut hash_data = end_hash.to_vec();
hash_data.push(ty);
hash_data.extend_from_slice(val);
hash(&hash_data)
}
pub fn hash_event(end_hash: &Sha256Hash, event: &Event) -> Sha256Hash {
match *event {
Event::Tick => *end_hash,
Event::Discovery { data } => extend_and_hash(end_hash, 1, &data),
Event::Claim { key, data, sig } => {
let mut event_data = data.to_vec();
event_data.extend_from_slice(&sig);
event_data.extend_from_slice(&key);
extend_and_hash(end_hash, 2, &event_data)
}
}
}
pub fn next_hash(start_hash: &Sha256Hash, num_hashes: u64, event: &Event) -> Sha256Hash {
let mut end_hash = *start_hash;
for _ in 0..num_hashes {
end_hash = hash(&end_hash);
}
hash_event(&end_hash, event)
}
pub fn next_entry(start_hash: &Sha256Hash, num_hashes: u64, event: Event) -> Entry {
Entry {
num_hashes,
end_hash: next_hash(start_hash, num_hashes, &event),
event,
}
}
pub fn next_tick(start_hash: &Sha256Hash, num_hashes: u64) -> Entry {
next_entry(start_hash, num_hashes, Event::Tick)
}
pub fn verify_slice(events: &[Entry], start_hash: &Sha256Hash) -> bool {
use rayon::prelude::*;
let genesis = [Entry::new_tick(Default::default(), start_hash)];
let event_pairs = genesis.par_iter().chain(events).zip(events);
event_pairs.all(|(x0, x1)| x1.verify(&x0.end_hash))
}
pub fn verify_slice_seq(events: &[Entry], start_hash: &Sha256Hash) -> bool {
let genesis = [Entry::new_tick(0, start_hash)];
let mut event_pairs = genesis.iter().chain(events).zip(events);
event_pairs.all(|(x0, x1)| x1.verify(&x0.end_hash))
}
pub fn verify_signature(peer_public_key_bytes: &[u8], msg_bytes: &[u8], sig_bytes: &[u8]) -> bool {
use untrusted;
use ring::signature;
let peer_public_key = untrusted::Input::from(peer_public_key_bytes);
let msg = untrusted::Input::from(msg_bytes);
let sig = untrusted::Input::from(sig_bytes);
signature::verify(&signature::ED25519, peer_public_key, msg, sig).is_ok()
}
pub fn create_ticks(start_hash: &Sha256Hash, num_hashes: u64, len: usize) -> Vec<Entry> {
use std::iter;
let mut end_hash = *start_hash;
iter::repeat(Event::Tick)
.take(len)
.map(|event| {
let entry = next_entry(&end_hash, num_hashes, event);
end_hash = entry.end_hash;
entry
})
.collect()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_event_verify() {
let zero = Sha256Hash::default();
let one = hash(&zero);
assert!(Entry::new_tick(0, &zero).verify(&zero));
assert!(!Entry::new_tick(0, &zero).verify(&one));
assert!(next_tick(&zero, 1).verify(&zero));
assert!(!next_tick(&zero, 1).verify(&one));
}
#[test]
fn test_next_tick() {
let zero = Sha256Hash::default();
assert_eq!(next_tick(&zero, 1).num_hashes, 1)
}
fn verify_slice_generic(verify_slice: fn(&[Entry], &Sha256Hash) -> bool) {
let zero = Sha256Hash::default();
let one = hash(&zero);
assert!(verify_slice(&vec![], &zero));
assert!(verify_slice(&vec![Entry::new_tick(0, &zero)], &zero));
assert!(!verify_slice(&vec![Entry::new_tick(0, &zero)], &one));
assert!(verify_slice(&create_ticks(&zero, 0, 2), &zero));
let mut bad_ticks = create_ticks(&zero, 0, 2);
bad_ticks[1].end_hash = one;
assert!(!verify_slice(&bad_ticks, &zero));
}
#[test]
fn test_verify_slice() {
verify_slice_generic(verify_slice);
}
#[test]
fn test_verify_slice_seq() {
verify_slice_generic(verify_slice_seq);
}
#[test]
fn test_reorder_attack() {
let zero = Sha256Hash::default();
let one = hash(&zero);
let mut end_hash = zero;
let events = [
Event::Discovery { data: zero },
Event::Discovery { data: one },
];
let mut entries: Vec<Entry> = events
.iter()
.map(|event| {
let entry = next_entry(&end_hash, 0, event.clone());
end_hash = entry.end_hash;
entry
})
.collect();
assert!(verify_slice(&entries, &zero));
let event0 = entries[0].event.clone();
let event1 = entries[1].event.clone();
entries[0].event = event1;
entries[1].event = event0;
assert!(!verify_slice(&entries, &zero));
}
#[test]
fn test_signature() {
use untrusted;
use ring::{rand, signature};
let rng = rand::SystemRandom::new();
let pkcs8_bytes = signature::Ed25519KeyPair::generate_pkcs8(&rng).unwrap();
let key_pair =
signature::Ed25519KeyPair::from_pkcs8(untrusted::Input::from(&pkcs8_bytes)).unwrap();
const MESSAGE: &'static [u8] = b"hello, world";
let event0 = sign_hash(&hash(MESSAGE), &key_pair);
let zero = Sha256Hash::default();
let mut end_hash = zero;
let entries: Vec<Entry> = [event0]
.iter()
.map(|event| {
let entry = next_entry(&end_hash, 0, event.clone());
end_hash = entry.end_hash;
entry
})
.collect();
assert!(verify_slice(&entries, &zero));
}
#[test]
fn test_bad_signature() {
use untrusted;
use ring::{rand, signature};
let rng = rand::SystemRandom::new();
let pkcs8_bytes = signature::Ed25519KeyPair::generate_pkcs8(&rng).unwrap();
let key_pair =
signature::Ed25519KeyPair::from_pkcs8(untrusted::Input::from(&pkcs8_bytes)).unwrap();
const MESSAGE: &'static [u8] = b"hello, world";
let mut event0 = sign_hash(&hash(MESSAGE), &key_pair);
if let Event::Claim { key, sig, .. } = event0 {
const GOODBYE: &'static [u8] = b"goodbye cruel world";
let data = hash(GOODBYE);
event0 = Event::Claim { key, data, sig };
}
let zero = Sha256Hash::default();
let mut end_hash = zero;
let entries: Vec<Entry> = [event0]
.iter()
.map(|event| {
let entry = next_entry(&end_hash, 0, event.clone());
end_hash = entry.end_hash;
entry
})
.collect();
assert!(!verify_slice(&entries, &zero));
}
}
#[cfg(all(feature = "unstable", test))]
mod bench {
extern crate test;
use self::test::Bencher;
use log::*;
#[bench]
fn event_bench(bencher: &mut Bencher) {
let start_hash = Default::default();
let events = create_ticks(&start_hash, 10_000, 8);
bencher.iter(|| {
assert!(verify_slice(&events, &start_hash));
});
}
#[bench]
fn event_bench_seq(bencher: &mut Bencher) {
let start_hash = Default::default();
let events = create_ticks(&start_hash, 10_000, 8);
bencher.iter(|| {
assert!(verify_slice_seq(&events, &start_hash));
});
}
}