Version bump

* Add asm, though it doesn't make it faster. TODO: use avx instructions.
* Do 10x less hashes, since sha256 is more expensive.

.codecov.yml

@@ -0,0 +1,2 @@
+ignore:
+  - "src/bin" 

.travis.yml

@@ -9,7 +9,7 @@ matrix:
   - rust: stable
   - rust: nightly
     env:
-    - FEATURES='unstable'
+    - FEATURES='asm,unstable'
 before_script: |
   export PATH="$PATH:$HOME/.cargo/bin"
   rustup component add rustfmt-preview

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "silk"
 description = "A silky smooth implementation of the Loom architecture"
-version = "0.1.3"
+version = "0.2.1"
 documentation = "https://docs.rs/silk"
 homepage = "http://loomprotocol.com/"
 repository = "https://github.com/loomprotocol/silk"
@@ -11,12 +11,20 @@ authors = [
 ]
 license = "Apache-2.0"
 
+[[bin]]
+name = "silk-demo"
+path = "src/bin/demo.rs"
+
 [badges]
 codecov = { repository = "loomprotocol/silk", branch = "master", service = "github" }
 
 [features]
 unstable = []
+asm = ["sha2-asm"]
 
 [dependencies]
 rayon = "1.0.0"
 itertools = "0.7.6"
+sha2 = "0.7.0"
+sha2-asm = {version="0.3", optional=true}
+digest = "0.7.2"

README.md

@@ -15,6 +15,54 @@ corresponding benchmarks are also added that demonstrate real performance boots.
 feature set here will always be a ways behind the loom repo, but that this is an implementation
 you can take to the bank, literally.
 
+# Usage
+
+Add the latest [silk package](https://crates.io/crates/silk) to the `[dependencies]` section
+of your Cargo.toml.
+
+Create a *Historian* and send it *events* to generate an *event log*, where each log *entry*
+is tagged with the historian's latest *hash*. Then ensure the order of events was not tampered
+with by verifying each entry's hash can be generated from the hash in the previous entry:
+
+```rust
+extern crate silk;
+
+use silk::historian::Historian;
+use silk::log::{verify_slice, Entry, Event, Sha256Hash};
+use std::{thread, time};
+use std::sync::mpsc::SendError;
+
+fn create_log(hist: &Historian) -> Result<(), SendError<Event>> {
+    hist.sender.send(Event::Tick)?;
+    thread::sleep(time::Duration::new(0, 100_000));
+    hist.sender.send(Event::UserDataKey(0xdeadbeef))?;
+    thread::sleep(time::Duration::new(0, 100_000));
+    hist.sender.send(Event::Tick)?;
+    Ok(())
+}
+
+fn main() {
+    let seed = Sha256Hash::default();
+    let hist = Historian::new(&seed);
+    create_log(&hist).expect("send error");
+    drop(hist.sender);
+    let entries: Vec<Entry> = hist.receiver.iter().collect();
+    for entry in &entries {
+        println!("{:?}", entry);
+    }
+    assert!(verify_slice(&entries, &seed));
+}
+```
+
+Running the program should produce a log similar to:
+
+```rust
+Entry { num_hashes: 0, end_hash: [0, ...], event: Tick }
+Entry { num_hashes: 6, end_hash: [67, ...], event: UserDataKey(3735928559) }
+Entry { num_hashes: 5, end_hash: [123, ...], event: Tick }
+```
+
+
 # Developing
 
 Building
@@ -56,5 +104,5 @@ $ rustup install nightly
 Run the benchmarks:
 
 ```bash
-$ cargo +nightly bench --features="unstable"
+$ cargo +nightly bench --features="asm,unstable"
 ```

src/bin/demo.rs

@@ -0,0 +1,27 @@
+extern crate silk;
+
+use silk::historian::Historian;
+use silk::log::{verify_slice, Entry, Event, Sha256Hash};
+use std::{thread, time};
+use std::sync::mpsc::SendError;
+
+fn create_log(hist: &Historian) -> Result<(), SendError<Event>> {
+    hist.sender.send(Event::Tick)?;
+    thread::sleep(time::Duration::new(0, 100_000));
+    hist.sender.send(Event::UserDataKey(0xdeadbeef))?;
+    thread::sleep(time::Duration::new(0, 100_000));
+    hist.sender.send(Event::Tick)?;
+    Ok(())
+}
+
+fn main() {
+    let seed = Sha256Hash::default();
+    let hist = Historian::new(&seed);
+    create_log(&hist).expect("send error");
+    drop(hist.sender);
+    let entries: Vec<Entry> = hist.receiver.iter().collect();
+    for entry in &entries {
+        println!("{:?}", entry);
+    }
+    assert!(verify_slice(&entries, &seed));
+}

src/event.rs

@@ -1,151 +0,0 @@
-//! The `event` crate provides the foundational data structures for Proof-of-History
-
-/// A Proof-of-History is an ordered log of events in time. Each entry contains three
-/// pieces of data. The 'num_hashes' field is the number of hashes performed since the previous
-/// entry.  The 'end_hash' field is the result of hashing 'end_hash' from the previous entry
-/// 'num_hashes' times.  The 'data' field is an optional foreign key (a hash) pointing to some
-/// arbitrary data that a client is looking to associate with the entry.
-///
-/// If you divide 'num_hashes' by the amount of time it takes to generate a new hash, you
-/// get a duration estimate since the last event. Since processing power increases
-/// over time, one should expect the duration 'num_hashes' represents to decrease proportionally.
-/// Though processing power varies across nodes, the network gives priority to the
-/// fastest processor. Duration should therefore be estimated by assuming that the hash
-/// was generated by the fastest processor at the time the entry was logged.
-pub struct Event {
-    pub num_hashes: u64,
-    pub end_hash: u64,
-    pub data: EventData,
-}
-
-/// When 'data' is Tick, the event represents a simple clock tick, and exists for the
-/// sole purpose of improving the performance of event log verification. A tick can
-/// be generated in 'num_hashes' hashes and verified in 'num_hashes' hashes.  By logging
-/// a hash alongside the tick, each tick and be verified in parallel using the 'end_hash'
-/// of the preceding tick to seed its hashing.
-pub enum EventData {
-    Tick,
-    UserDataKey(u64),
-}
-
-impl Event {
-    /// Creates an Event from the number of hashes 'num_hashes' since the previous event
-    /// and that resulting 'end_hash'.
-    pub fn new_tick(num_hashes: u64, end_hash: u64) -> Self {
-        let data = EventData::Tick;
-        Event {
-            num_hashes,
-            end_hash,
-            data,
-        }
-    }
-
-    /// Verifies self.end_hash is the result of hashing a 'start_hash' 'self.num_hashes' times.
-    pub fn verify(self: &Self, start_hash: u64) -> bool {
-        self.end_hash == next_tick(start_hash, self.num_hashes).end_hash
-    }
-}
-
-/// Creates the next Tick Event 'num_hashes' after 'start_hash'.
-pub fn next_tick(start_hash: u64, num_hashes: u64) -> Event {
-    use std::collections::hash_map::DefaultHasher;
-    use std::hash::{Hash, Hasher};
-    let mut end_hash = start_hash;
-    let mut hasher = DefaultHasher::new();
-    for _ in 0..num_hashes {
-        end_hash.hash(&mut hasher);
-        end_hash = hasher.finish();
-    }
-    Event::new_tick(num_hashes, end_hash)
-}
-
-/// Verifies the hashes and counts of a slice of events are all consistent.
-pub fn verify_slice(events: &[Event], start_hash: u64) -> bool {
-    use rayon::prelude::*;
-    let genesis = [Event::new_tick(0, start_hash)];
-    let event_pairs = genesis.par_iter().chain(events).zip(events);
-    event_pairs.all(|(x0, x1)| x1.verify(x0.end_hash))
-}
-
-/// Verifies the hashes and events serially. Exists only for reference.
-pub fn verify_slice_seq(events: &[Event], start_hash: u64) -> bool {
-    let genesis = [Event::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))
-}
-
-/// Create a vector of Ticks of length 'len' from 'start_hash' hash and 'num_hashes'.
-pub fn create_ticks(start_hash: u64, num_hashes: u64, len: usize) -> Vec<Event> {
-    use itertools::unfold;
-    let mut events = unfold(start_hash, |state| {
-        let event = next_tick(*state, num_hashes);
-        *state = event.end_hash;
-        return Some(event);
-    });
-    events.by_ref().take(len).collect()
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_event_verify() {
-        assert!(Event::new_tick(0, 0).verify(0)); // base case
-        assert!(!Event::new_tick(0, 0).verify(1)); // base case, bad
-        assert!(next_tick(0, 1).verify(0)); // inductive step
-        assert!(!next_tick(0, 1).verify(1)); // inductive step, bad
-    }
-
-    #[test]
-    fn test_next_tick() {
-        assert_eq!(next_tick(0, 1).num_hashes, 1)
-    }
-
-    fn verify_slice_generic(verify_slice: fn(&[Event], u64) -> bool) {
-        assert!(verify_slice(&vec![], 0)); // base case
-        assert!(verify_slice(&vec![Event::new_tick(0, 0)], 0)); // singleton case 1
-        assert!(!verify_slice(&vec![Event::new_tick(0, 0)], 1)); // singleton case 2, bad
-        assert!(verify_slice(&create_ticks(0, 0, 2), 0)); // inductive step
-
-        let mut bad_ticks = create_ticks(0, 0, 2);
-        bad_ticks[1].end_hash = 1;
-        assert!(!verify_slice(&bad_ticks, 0)); // inductive step, bad
-    }
-
-    #[test]
-    fn test_verify_slice() {
-        verify_slice_generic(verify_slice);
-    }
-
-    #[test]
-    fn test_verify_slice_seq() {
-        verify_slice_generic(verify_slice_seq);
-    }
-
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod bench {
-    extern crate test;
-    use self::test::Bencher;
-    use event;
-
-    #[bench]
-    fn event_bench(bencher: &mut Bencher) {
-        let start_hash = 0;
-        let events = event::create_ticks(start_hash, 100_000, 8);
-        bencher.iter(|| {
-            assert!(event::verify_slice(&events, start_hash));
-        });
-    }
-
-    #[bench]
-    fn event_bench_seq(bencher: &mut Bencher) {
-        let start_hash = 0;
-        let events = event::create_ticks(start_hash, 100_000, 8);
-        bencher.iter(|| {
-            assert!(event::verify_slice_seq(&events, start_hash));
-        });
-    }
-}

src/historian.rs

@@ -0,0 +1,139 @@
+//! The `historian` crate provides a microservice for generating a Proof-of-History.
+//! It logs Event items on behalf of its users. It continuously generates
+//! new hashes, only stopping to check if it has been sent an Event item. It
+//! tags each Event with an Entry and sends it back. The Entry includes the
+//! Event, the latest hash, and the number of hashes since the last event.
+//! The resulting stream of entries represents ordered events in time.
+
+use std::thread::JoinHandle;
+use std::sync::mpsc::{Receiver, Sender};
+use log::{hash, Entry, Event, Sha256Hash};
+
+pub struct Historian {
+    pub sender: Sender<Event>,
+    pub receiver: Receiver<Entry>,
+    pub thread_hdl: JoinHandle<(Entry, ExitReason)>,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum ExitReason {
+    RecvDisconnected,
+    SendDisconnected,
+}
+
+fn log_events(
+    receiver: &Receiver<Event>,
+    sender: &Sender<Entry>,
+    num_hashes: u64,
+    end_hash: Sha256Hash,
+) -> Result<u64, (Entry, ExitReason)> {
+    use std::sync::mpsc::TryRecvError;
+    let mut num_hashes = num_hashes;
+    loop {
+        match receiver.try_recv() {
+            Ok(event) => {
+                let entry = Entry {
+                    end_hash,
+                    num_hashes,
+                    event,
+                };
+                if let Err(_) = sender.send(entry.clone()) {
+                    return Err((entry, ExitReason::SendDisconnected));
+                }
+                num_hashes = 0;
+            }
+            Err(TryRecvError::Empty) => {
+                return Ok(num_hashes);
+            }
+            Err(TryRecvError::Disconnected) => {
+                let entry = Entry {
+                    end_hash,
+                    num_hashes,
+                    event: Event::Tick,
+                };
+                return Err((entry, ExitReason::RecvDisconnected));
+            }
+        }
+    }
+}
+
+/// A background thread that will continue tagging received Event messages and
+/// sending back Entry messages until either the receiver or sender channel is closed.
+pub fn create_logger(
+    start_hash: Sha256Hash,
+    receiver: Receiver<Event>,
+    sender: Sender<Entry>,
+) -> JoinHandle<(Entry, ExitReason)> {
+    use std::thread;
+    thread::spawn(move || {
+        let mut end_hash = start_hash;
+        let mut num_hashes = 0;
+        loop {
+            match log_events(&receiver, &sender, num_hashes, end_hash) {
+                Ok(n) => num_hashes = n,
+                Err(err) => return err,
+            }
+            end_hash = hash(&end_hash);
+            num_hashes += 1;
+        }
+    })
+}
+
+impl Historian {
+    pub fn new(start_hash: &Sha256Hash) -> Self {
+        use std::sync::mpsc::channel;
+        let (sender, event_receiver) = channel();
+        let (entry_sender, receiver) = channel();
+        let thread_hdl = create_logger(*start_hash, event_receiver, entry_sender);
+        Historian {
+            sender,
+            receiver,
+            thread_hdl,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use log::*;
+
+    #[test]
+    fn test_historian() {
+        use std::thread::sleep;
+        use std::time::Duration;
+
+        let zero = Sha256Hash::default();
+        let hist = Historian::new(&zero);
+
+        hist.sender.send(Event::Tick).unwrap();
+        sleep(Duration::new(0, 1_000_000));
+        hist.sender.send(Event::UserDataKey(0xdeadbeef)).unwrap();
+        sleep(Duration::new(0, 1_000_000));
+        hist.sender.send(Event::Tick).unwrap();
+
+        let entry0 = hist.receiver.recv().unwrap();
+        let entry1 = hist.receiver.recv().unwrap();
+        let entry2 = hist.receiver.recv().unwrap();
+
+        drop(hist.sender);
+        assert_eq!(
+            hist.thread_hdl.join().unwrap().1,
+            ExitReason::RecvDisconnected
+        );
+
+        assert!(verify_slice(&[entry0, entry1, entry2], &zero));
+    }
+
+    #[test]
+    fn test_historian_closed_sender() {
+        let zero = Sha256Hash::default();
+        let hist = Historian::new(&zero);
+        drop(hist.receiver);
+        hist.sender.send(Event::Tick).unwrap();
+        assert_eq!(
+            hist.thread_hdl.join().unwrap().1,
+            ExitReason::SendDisconnected
+        );
+    }
+}

src/lib.rs

@@ -1,4 +1,7 @@
 #![cfg_attr(feature = "unstable", feature(test))]
-pub mod event;
+pub mod log;
+pub mod historian;
+extern crate digest;
 extern crate itertools;
 extern crate rayon;
+extern crate sha2;

src/log.rs

@@ -0,0 +1,166 @@
+//! The `log` crate provides the foundational data structures for Proof-of-History,
+//! an ordered log of events in time.
+
+/// Each log entry contains three pieces of data. The 'num_hashes' field is the number
+/// of hashes performed since the previous entry.  The 'end_hash' field is the result
+/// of hashing 'end_hash' from the previous entry 'num_hashes' times.  The 'event'
+/// field points to an Event that took place shortly after 'end_hash' was generated.
+///
+/// If you divide 'num_hashes' by the amount of time it takes to generate a new hash, you
+/// get a duration estimate since the last event. Since processing power increases
+/// over time, one should expect the duration 'num_hashes' represents to decrease proportionally.
+/// Though processing power varies across nodes, the network gives priority to the
+/// fastest processor. Duration should therefore be estimated by assuming that the hash
+/// was generated by the fastest processor at the time the entry was logged.
+
+use digest::generic_array::GenericArray;
+use digest::generic_array::typenum::U32;
+pub type Sha256Hash = GenericArray<u8, U32>;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Entry {
+    pub num_hashes: u64,
+    pub end_hash: Sha256Hash,
+    pub event: Event,
+}
+
+/// When 'event' is Tick, the event represents a simple clock tick, and exists for the
+/// sole purpose of improving the performance of event log verification. A tick can
+/// be generated in 'num_hashes' hashes and verified in 'num_hashes' hashes.  By logging
+/// a hash alongside the tick, each tick and be verified in parallel using the 'end_hash'
+/// of the preceding tick to seed its hashing.
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Event {
+    Tick,
+    UserDataKey(u64),
+}
+
+impl Entry {
+    /// Creates a Entry from the number of hashes 'num_hashes' since the previous event
+    /// and that resulting 'end_hash'.
+    pub fn new_tick(num_hashes: u64, end_hash: &Sha256Hash) -> Self {
+        let event = Event::Tick;
+        Entry {
+            num_hashes,
+            end_hash: *end_hash,
+            event,
+        }
+    }
+
+    /// Verifies self.end_hash is the result of hashing a 'start_hash' 'self.num_hashes' times.
+    pub fn verify(self: &Self, start_hash: &Sha256Hash) -> bool {
+        self.end_hash == next_tick(start_hash, self.num_hashes).end_hash
+    }
+}
+
+pub fn hash(val: &[u8]) -> Sha256Hash {
+    use sha2::{Digest, Sha256};
+    let mut hasher = Sha256::default();
+    hasher.input(val);
+    hasher.result()
+}
+
+/// Creates the next Tick Entry 'num_hashes' after 'start_hash'.
+pub fn next_tick(start_hash: &Sha256Hash, num_hashes: u64) -> Entry {
+    let mut end_hash = *start_hash;
+    for _ in 0..num_hashes {
+        end_hash = hash(&end_hash);
+    }
+    Entry::new_tick(num_hashes, &end_hash)
+}
+
+/// Verifies the hashes and counts of a slice of events are all consistent.
+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))
+}
+
+/// Verifies the hashes and events serially. Exists only for reference.
+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))
+}
+
+/// Create a vector of Ticks of length 'len' from 'start_hash' hash and 'num_hashes'.
+pub fn create_ticks(start_hash: &Sha256Hash, num_hashes: u64, len: usize) -> Vec<Entry> {
+    use itertools::unfold;
+    let mut events = unfold(*start_hash, |state| {
+        let event = next_tick(state, num_hashes);
+        *state = event.end_hash;
+        return Some(event);
+    });
+    events.by_ref().take(len).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)); // base case
+        assert!(!Entry::new_tick(0, &zero).verify(&one)); // base case, bad
+        assert!(next_tick(&zero, 1).verify(&zero)); // inductive step
+        assert!(!next_tick(&zero, 1).verify(&one)); // inductive step, bad
+    }
+
+    #[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)); // base case
+        assert!(verify_slice(&vec![Entry::new_tick(0, &zero)], &zero)); // singleton case 1
+        assert!(!verify_slice(&vec![Entry::new_tick(0, &zero)], &one)); // singleton case 2, bad
+        assert!(verify_slice(&create_ticks(&zero, 0, 2), &zero)); // inductive step
+
+        let mut bad_ticks = create_ticks(&zero, 0, 2);
+        bad_ticks[1].end_hash = one;
+        assert!(!verify_slice(&bad_ticks, &zero)); // inductive step, bad
+    }
+
+    #[test]
+    fn test_verify_slice() {
+        verify_slice_generic(verify_slice);
+    }
+
+    #[test]
+    fn test_verify_slice_seq() {
+        verify_slice_generic(verify_slice_seq);
+    }
+
+}
+
+#[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));
+        });
+    }
+}