Delete the Discovery event

Not useful to the accountant.

README.md

@@ -45,7 +45,7 @@ use std::sync::mpsc::SendError;
 fn create_log(hist: &Historian) -> Result<(), SendError<Event>> {
     sleep(Duration::from_millis(15));
     let data = Sha256Hash::default();
-    hist.sender.send(Event::Discovery { data })?;
+    hist.sender.send(Event::Claim { data })?;
     sleep(Duration::from_millis(10));
     Ok(())
 }
@@ -70,7 +70,7 @@ Running the program should produce a log similar to:
 
 ```rust
 Entry { num_hashes: 0, end_hash: [0, ...], event: Tick }
-Entry { num_hashes: 2, end_hash: [67, ...], event: Discovery { data: [37, ...] } }
+Entry { num_hashes: 2, end_hash: [67, ...], event: Claim { data: [37, ...] } }
 Entry { num_hashes: 3, end_hash: [123, ...], event: Tick }
 ```
 

diagrams/historian.msc

@@ -4,10 +4,10 @@ msc {
   logger=>historian [ label = "e0 = Entry{hash: h0, n: 0, event: Tick}" ] ;
   logger=>logger [ label = "h1 = hash(h0)" ] ;
   logger=>logger [ label = "h2 = hash(h1)" ] ;
-  client=>historian [ label = "Discovery(d0)" ] ;
-  historian=>logger [ label = "Discovery(d0)" ] ;
+  client=>historian [ label = "Claim(d0)" ] ;
+  historian=>logger [ label = "Claim(d0)" ] ;
   logger=>logger [ label = "h3 = hash(h2 + d0)" ] ;
-  logger=>historian [ label = "e1 = Entry{hash: hash(h3), n: 2, event: Discovery(d0)}" ] ;
+  logger=>historian [ label = "e1 = Entry{hash: hash(h3), n: 2, event: Claim(d0)}" ] ;
   logger=>logger [ label = "h4 = hash(h3)" ] ;
   logger=>logger [ label = "h5 = hash(h4)" ] ;
   logger=>logger [ label = "h6 = hash(h5)" ] ;

src/bin/demo.rs

@@ -1,7 +1,8 @@
 extern crate silk;
 
 use silk::historian::Historian;
-use silk::log::{verify_slice, Entry, Event, Sha256Hash};
+use silk::log::{generate_keypair, get_pubkey, sign_serialized, verify_slice, Entry, Event,
+                Sha256Hash};
 use std::thread::sleep;
 use std::time::Duration;
 use std::sync::mpsc::SendError;
@@ -9,7 +10,13 @@ use std::sync::mpsc::SendError;
 fn create_log(hist: &Historian<Sha256Hash>) -> Result<(), SendError<Event<Sha256Hash>>> {
     sleep(Duration::from_millis(15));
     let data = Sha256Hash::default();
-    hist.sender.send(Event::Discovery { data })?;
+    let keypair = generate_keypair();
+    let event0 = Event::Claim {
+        key: get_pubkey(&keypair),
+        data,
+        sig: sign_serialized(&data, &keypair),
+    };
+    hist.sender.send(event0)?;
     sleep(Duration::from_millis(10));
     Ok(())
 }

src/historian.rs

@@ -141,7 +141,7 @@ mod tests {
 
         hist.sender.send(Event::Tick).unwrap();
         sleep(Duration::new(0, 1_000_000));
-        hist.sender.send(Event::Discovery { data: zero }).unwrap();
+        hist.sender.send(Event::Tick).unwrap();
         sleep(Duration::new(0, 1_000_000));
         hist.sender.send(Event::Tick).unwrap();
 
@@ -175,7 +175,7 @@ mod tests {
         let zero = Sha256Hash::default();
         let hist = Historian::new(&zero, Some(20));
         sleep(Duration::from_millis(30));
-        hist.sender.send(Event::Discovery { data: zero }).unwrap();
+        hist.sender.send(Event::Tick).unwrap();
         sleep(Duration::from_millis(15));
         drop(hist.sender);
         assert_eq!(

src/log.rs

@@ -37,9 +37,6 @@ pub struct Entry<T> {
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
 pub enum Event<T> {
     Tick,
-    Discovery {
-        data: T,
-    },
     Claim {
         key: PublicKey,
         data: T,
@@ -111,11 +108,9 @@ pub fn extend_and_hash(end_hash: &Sha256Hash, ty: u8, val: &[u8]) -> Sha256Hash
     hash(&hash_data)
 }
 
-pub fn hash_event<T: Serialize>(end_hash: &Sha256Hash, event: &Event<T>) -> Sha256Hash {
-    use bincode::serialize;
+pub fn hash_event<T>(end_hash: &Sha256Hash, event: &Event<T>) -> Sha256Hash {
     match *event {
         Event::Tick => *end_hash,
-        Event::Discovery { ref data } => extend_and_hash(end_hash, 1, &serialize(&data).unwrap()),
         Event::Claim { sig, .. } => extend_and_hash(end_hash, 2, &sig),
         Event::Transaction { sig, .. } => extend_and_hash(end_hash, 3, &sig),
     }
@@ -302,15 +297,24 @@ mod tests {
         let zero = Sha256Hash::default();
         let one = hash(&zero);
 
-        // First, verify Discovery events
-        let events = vec![
-            Event::Discovery { data: zero },
-            Event::Discovery { data: one },
-        ];
+        // First, verify Claim events
+        let keypair = generate_keypair();
+        let event0 = Event::Claim {
+            key: get_pubkey(&keypair),
+            data: zero,
+            sig: sign_serialized(&zero, &keypair),
+        };
+
+        let event1 = Event::Claim {
+            key: get_pubkey(&keypair),
+            data: one,
+            sig: sign_serialized(&one, &keypair),
+        };
+        let events = vec![event0, event1];
         let mut entries = create_entries(&zero, 0, events);
         assert!(verify_slice(&entries, &zero));
 
-        // Next, swap two Discovery events and ensure verification fails.
+        // Next, swap two Claim events and ensure verification fails.
         let event0 = entries[0].event.clone();
         let event1 = entries[1].event.clone();
         entries[0].event = event1;