diff --git a/Cargo.toml b/Cargo.toml
index 31e6919a42..47e88ac8d7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,3 +29,5 @@ sha2-asm = {version="0.3", optional=true}
 generic-array = { version = "0.9.0", default-features = false, features = ["serde"] }
 serde = "1.0.27"
 serde_derive = "1.0.27"
+ring = "0.12.1"
+untrusted = "0.5.1"
diff --git a/src/historian.rs b/src/historian.rs
index 606997f956..8312272d9e 100644
--- a/src/historian.rs
+++ b/src/historian.rs
@@ -8,7 +8,7 @@
 use std::thread::JoinHandle;
 use std::sync::mpsc::{Receiver, Sender};
 use std::time::{Duration, SystemTime};
-use log::{extend_and_hash, hash, Entry, Event, Sha256Hash};
+use log::{hash, hash_event, Entry, Event, Sha256Hash};
 
 pub struct Historian {
     pub sender: Sender<Event>,
@@ -27,9 +27,7 @@ fn log_event(
     end_hash: &mut Sha256Hash,
     event: Event,
 ) -> Result<(), (Entry, ExitReason)> {
-    if let Event::Discovery(key) = event {
-        *end_hash = extend_and_hash(end_hash, &key);
-    }
+    *end_hash = hash_event(end_hash, &event);
     let entry = Entry {
         end_hash: *end_hash,
         num_hashes: *num_hashes,
diff --git a/src/lib.rs b/src/lib.rs
index 3ccb87efc5..2765660520 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,7 +3,9 @@ pub mod log;
 pub mod historian;
 extern crate generic_array;
 extern crate rayon;
+extern crate ring;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
 extern crate sha2;
+extern crate untrusted;
diff --git a/src/log.rs b/src/log.rs
index 23c48fb7e6..668fe55891 100644
--- a/src/log.rs
+++ b/src/log.rs
@@ -14,8 +14,11 @@
 /// was generated by the fastest processor at the time the entry was logged.
 
 use generic_array::GenericArray;
-use generic_array::typenum::U32;
+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 {
@@ -33,6 +36,11 @@ pub struct Entry {
 pub enum Event {
     Tick,
     Discovery(Sha256Hash),
+    Claim {
+        key: PublicKey,
+        data: Sha256Hash,
+        sig: Signature,
+    },
 }
 
 impl Entry {
@@ -49,10 +57,28 @@ impl Entry {
     /// Verifies self.end_hash is the result of hashing a 'start_hash' 'self.num_hashes' times.
     /// If the event is not a Tick, then hash that as well.
     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)
     }
 }
 
+/// Return a Claim Event for the given hash and key-pair.
+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),
+    }
+}
+
+/// Return a Sha256 hash for the given data.
 pub fn hash(val: &[u8]) -> Sha256Hash {
     use sha2::{Digest, Sha256};
     let mut hasher = Sha256::default();
@@ -61,21 +87,32 @@ pub fn hash(val: &[u8]) -> Sha256Hash {
 }
 
 /// Return the hash of the given hash extended with the given value.
-pub fn extend_and_hash(end_hash: &Sha256Hash, val: &[u8]) -> Sha256Hash {
+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);
     }
-    if let Event::Discovery(data) = *event {
-        return extend_and_hash(&end_hash, &data);
-    }
-    end_hash
+    hash_event(&end_hash, event)
 }
 
 /// Creates the next Tick Entry 'num_hashes' after 'start_hash'.
@@ -107,6 +144,16 @@ pub fn verify_slice_seq(events: &[Entry], start_hash: &Sha256Hash) -> bool {
     event_pairs.all(|(x0, x1)| x1.verify(&x0.end_hash))
 }
 
+/// Verify a signed message with the given public key.
+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()
+}
+
 /// 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 std::iter;
@@ -180,16 +227,38 @@ mod tests {
                 entry
             })
             .collect();
-        assert!(verify_slice(&entries, &zero)); // inductive step
+        assert!(verify_slice(&entries, &zero));
 
         // Next, swap two Discovery events and ensure verification fails.
         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)); // inductive step
+        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));
+    }
 }
 
 #[cfg(all(feature = "unstable", test))]