Merge pull request #55 from garious/the-mint

More intuitive demo, introducing The Mint

Cargo.toml

@@ -12,8 +12,8 @@ authors = [
 license = "Apache-2.0"
 
 [[bin]]
-name = "silk-demo"
-path = "src/bin/demo.rs"
+name = "silk-historian-demo"
+path = "src/bin/historian-demo.rs"
 
 [[bin]]
 name = "silk-client-demo"
@@ -24,12 +24,16 @@ name = "silk-testnode"
 path = "src/bin/testnode.rs"
 
 [[bin]]
-name = "silk-genesis-block"
-path = "src/bin/genesis-block.rs"
+name = "silk-genesis"
+path = "src/bin/genesis.rs"
 
 [[bin]]
-name = "silk-genesis-file-demo"
-path = "src/bin/genesis-file-demo.rs"
+name = "silk-genesis-demo"
+path = "src/bin/genesis-demo.rs"
+
+[[bin]]
+name = "silk-mint"
+path = "src/bin/mint.rs"
 
 [badges]
 codecov = { repository = "loomprotocol/silk", branch = "master", service = "github" }

README.md

@@ -32,27 +32,27 @@ First, build the demo executables in release mode (optimized for performance):
 ```
 
 The testnode server is initialized with a transaction log from stdin and
-generates a log on stdout. To create the input log, we'll need to create
-a *genesis* configuration file and then generate a log from it. It's done
-in two steps here because the demo-genesis.json file contains a private
-key that will be used later in this demo.
+generates new log entries on stdout. To create the input log, we'll need
+to create *the mint* and use it to generate a *genesis log*. It's done in
+two steps because the mint.json file contains a private key that will be
+used later in this demo.
 
 ```bash
-    $ ./silk-genesis-file-demo > demo-genesis.json
-    $ cat demo-genesis.json | ./silk-genesis-block > demo-genesis.log
+    $ echo 500 | ./silk-mint > mint.json
+    $ cat mint.json | ./silk-genesis > genesis.log
 ```
 
 Now you can start the server:
 
 ```bash
-    $ cat demo-genesis.log | ./silk-testnode > demo-entries0.log
+    $ cat genesis.log | ./silk-testnode > transactions0.log
 ```
 
 Then, in a separate shell, let's execute some transactions. Note we pass in
 the JSON configuration file here, not the genesis log.
 
 ```bash
-    $ cat demo-genesis.json | ./silk-client-demo
+    $ cat mint.json | ./silk-client-demo
 ```
 
 Now kill the server with Ctrl-C, and take a look at the transaction log. You should
@@ -68,7 +68,7 @@ Now restart the server from where we left off. Pass it both the genesis log, and
 the transaction log.
 
 ```bash
-    $ cat demo-genesis.log demo-entries0.log | ./silk-testnode > demo-entries1.log
+    $ cat genesis.log transactions0.log | ./silk-testnode > transactions1.log
 ```
 
 Lastly, run the client demo again, and verify that all funds were spent in the

src/accountant.rs

@@ -7,7 +7,7 @@ use entry::Entry;
 use event::Event;
 use transaction::Transaction;
 use signature::{KeyPair, PublicKey, Signature};
-use genesis::Genesis;
+use mint::Mint;
 use historian::{reserve_signature, Historian};
 use std::sync::mpsc::SendError;
 use std::collections::HashMap;
@@ -62,8 +62,8 @@ impl Accountant {
         acc
     }
 
-    pub fn new(gen: &Genesis, ms_per_tick: Option<u64>) -> Self {
-        Self::new_from_entries(gen.create_entries(), ms_per_tick)
+    pub fn new(mint: &Mint, ms_per_tick: Option<u64>) -> Self {
+        Self::new_from_entries(mint.create_entries(), ms_per_tick)
     }
 
     pub fn sync(self: &mut Self) -> Hash {
@@ -146,19 +146,18 @@ impl Accountant {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use signature::{generate_keypair, get_pubkey};
+    use signature::KeyPairUtil;
     use logger::ExitReason;
 
     #[test]
     fn test_accountant() {
-        let alice = Genesis::new(10_000);
-        let bob_pubkey = get_pubkey(&generate_keypair());
+        let alice = Mint::new(10_000);
+        let bob_pubkey = KeyPair::new().pubkey();
         let mut acc = Accountant::new(&alice, Some(2));
-        acc.transfer(1_000, &alice.get_keypair(), bob_pubkey)
-            .unwrap();
+        acc.transfer(1_000, &alice.keypair(), bob_pubkey).unwrap();
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap(), 1_000);
 
-        acc.transfer(500, &alice.get_keypair(), bob_pubkey).unwrap();
+        acc.transfer(500, &alice.keypair(), bob_pubkey).unwrap();
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap(), 1_500);
 
         drop(acc.historian.sender);
@@ -170,17 +169,16 @@ mod tests {
 
     #[test]
     fn test_invalid_transfer() {
-        let alice = Genesis::new(11_000);
+        let alice = Mint::new(11_000);
         let mut acc = Accountant::new(&alice, Some(2));
-        let bob_pubkey = get_pubkey(&generate_keypair());
-        acc.transfer(1_000, &alice.get_keypair(), bob_pubkey)
-            .unwrap();
+        let bob_pubkey = KeyPair::new().pubkey();
+        acc.transfer(1_000, &alice.keypair(), bob_pubkey).unwrap();
         assert_eq!(
-            acc.transfer(10_001, &alice.get_keypair(), bob_pubkey),
+            acc.transfer(10_001, &alice.keypair(), bob_pubkey),
             Err(AccountingError::InsufficientFunds)
         );
 
-        let alice_pubkey = get_pubkey(&alice.get_keypair());
+        let alice_pubkey = alice.keypair().pubkey();
         assert_eq!(acc.get_balance(&alice_pubkey).unwrap(), 10_000);
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap(), 1_000);
 
@@ -193,10 +191,10 @@ mod tests {
 
     #[test]
     fn test_transfer_to_newb() {
-        let alice = Genesis::new(10_000);
+        let alice = Mint::new(10_000);
         let mut acc = Accountant::new(&alice, Some(2));
-        let alice_keypair = alice.get_keypair();
-        let bob_pubkey = get_pubkey(&generate_keypair());
+        let alice_keypair = alice.keypair();
+        let bob_pubkey = KeyPair::new().pubkey();
         acc.transfer(500, &alice_keypair, bob_pubkey).unwrap();
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap(), 500);
 

src/accountant_stub.rs

@@ -115,23 +115,23 @@ mod tests {
     use accountant_skel::AccountantSkel;
     use std::thread::{sleep, spawn};
     use std::time::Duration;
-    use genesis::Genesis;
-    use signature::{generate_keypair, get_pubkey};
+    use mint::Mint;
+    use signature::{KeyPair, KeyPairUtil};
 
     #[test]
     fn test_accountant_stub() {
         let addr = "127.0.0.1:9000";
         let send_addr = "127.0.0.1:9001";
-        let alice = Genesis::new(10_000);
+        let alice = Mint::new(10_000);
         let acc = Accountant::new(&alice, None);
-        let bob_pubkey = get_pubkey(&generate_keypair());
+        let bob_pubkey = KeyPair::new().pubkey();
         spawn(move || AccountantSkel::new(acc).serve(addr).unwrap());
         sleep(Duration::from_millis(30));
 
         let socket = UdpSocket::bind(send_addr).unwrap();
         let mut acc = AccountantStub::new(addr, socket);
         let last_id = acc.get_last_id().unwrap();
-        let sig = acc.transfer(500, &alice.get_keypair(), bob_pubkey, &last_id)
+        let sig = acc.transfer(500, &alice.keypair(), bob_pubkey, &last_id)
             .unwrap();
         acc.wait_on_signature(&sig).unwrap();
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap().unwrap(), 500);

src/bin/client-demo.rs

@@ -2,9 +2,9 @@ extern crate serde_json;
 extern crate silk;
 
 use silk::accountant_stub::AccountantStub;
-use silk::signature::{generate_keypair, get_pubkey};
+use silk::signature::{KeyPair, KeyPairUtil};
 use silk::transaction::Transaction;
-use silk::genesis::Genesis;
+use silk::mint::Mint;
 use std::time::Instant;
 use std::net::UdpSocket;
 use std::io::stdin;
@@ -13,23 +13,23 @@ fn main() {
     let addr = "127.0.0.1:8000";
     let send_addr = "127.0.0.1:8001";
 
-    let gen: Genesis = serde_json::from_reader(stdin()).unwrap();
-    let alice_keypair = gen.get_keypair();
-    let alice_pubkey = gen.get_pubkey();
+    let mint: Mint = serde_json::from_reader(stdin()).unwrap();
+    let mint_keypair = mint.keypair();
+    let mint_pubkey = mint.pubkey();
 
     let socket = UdpSocket::bind(send_addr).unwrap();
     let mut acc = AccountantStub::new(addr, socket);
     let last_id = acc.get_last_id().unwrap();
 
-    let txs = acc.get_balance(&alice_pubkey).unwrap().unwrap();
-    println!("Alice's Initial Balance {}", txs);
+    let txs = acc.get_balance(&mint_pubkey).unwrap().unwrap();
+    println!("Mint's Initial Balance {}", txs);
 
     println!("Signing transactions...");
     let now = Instant::now();
     let transactions: Vec<_> = (0..txs)
         .map(|_| {
-            let rando_pubkey = get_pubkey(&generate_keypair());
-            Transaction::new(&alice_keypair, rando_pubkey, 1, last_id)
+            let rando_pubkey = KeyPair::new().pubkey();
+            Transaction::new(&mint_keypair, rando_pubkey, 1, last_id)
         })
         .collect();
     let duration = now.elapsed();
@@ -71,7 +71,7 @@ fn main() {
     let ns = duration.as_secs() * 1_000_000_000 + duration.subsec_nanos() as u64;
     let tps = (txs * 1_000_000_000) as f64 / ns as f64;
     println!("Done. {} tps!", tps);
-    let val = acc.get_balance(&alice_pubkey).unwrap().unwrap();
-    println!("Alice's Final Balance {}", val);
+    let val = acc.get_balance(&mint_pubkey).unwrap().unwrap();
+    println!("Mint's Final Balance {}", val);
     assert_eq!(val, 0);
 }

src/bin/genesis-block.rs

@@ -1,18 +0,0 @@
-//! A command-line executable for generating the chain's genesis block.
-
-extern crate ring;
-extern crate serde_json;
-extern crate silk;
-
-use silk::genesis::Genesis;
-use silk::log::verify_slice;
-use std::io::stdin;
-
-fn main() {
-    let gen: Genesis = serde_json::from_reader(stdin()).unwrap();
-    let entries = gen.create_entries();
-    verify_slice(&entries, &entries[0].id);
-    for x in entries {
-        println!("{}", serde_json::to_string(&x).unwrap());
-    }
-}

src/bin/genesis-demo.rs

@@ -1,30 +1,30 @@
 extern crate serde_json;
 extern crate silk;
 
-use silk::genesis::Genesis;
+use silk::mint::Mint;
 use silk::event::Event;
 use silk::transaction::Transaction;
 use silk::log::create_entries;
-use silk::signature::{generate_keypair, get_pubkey, KeyPair, PublicKey};
+use silk::signature::{KeyPair, KeyPairUtil, PublicKey};
 use silk::hash::Hash;
+use std::io::stdin;
 
 fn transfer(from: &KeyPair, (to, tokens): (PublicKey, i64), last_id: Hash) -> Event {
     Event::Transaction(Transaction::new(&from, to, tokens, last_id))
 }
 
 fn main() {
-    let alice = (get_pubkey(&generate_keypair()), 200);
-    let bob = (get_pubkey(&generate_keypair()), 100);
+    let alice = (KeyPair::new().pubkey(), 200);
+    let bob = (KeyPair::new().pubkey(), 100);
 
-    let gen = Genesis::new(500);
-    let from = gen.get_keypair();
-    let seed = gen.get_seed();
-    let mut events = gen.create_events();
+    let mint: Mint = serde_json::from_reader(stdin()).unwrap();
+    let from = mint.keypair();
+    let seed = mint.seed();
+    let mut events = mint.create_events();
     events.push(transfer(&from, alice, seed));
     events.push(transfer(&from, bob, seed));
 
-    let entries = create_entries(&seed, events);
-    for entry in entries {
+    for entry in create_entries(&seed, events) {
         println!("{}", serde_json::to_string(&entry).unwrap());
     }
 }

src/bin/genesis.rs

@@ -0,0 +1,14 @@
+//! A command-line executable for generating the chain's genesis block.
+
+extern crate serde_json;
+extern crate silk;
+
+use silk::mint::Mint;
+use std::io::stdin;
+
+fn main() {
+    let mint: Mint = serde_json::from_reader(stdin()).unwrap();
+    for x in mint.create_entries() {
+        println!("{}", serde_json::to_string(&x).unwrap());
+    }
+}

src/bin/historian-demo.rs

@@ -4,7 +4,7 @@ use silk::historian::Historian;
 use silk::hash::Hash;
 use silk::entry::Entry;
 use silk::log::verify_slice;
-use silk::signature::{generate_keypair, get_pubkey};
+use silk::signature::{KeyPair, KeyPairUtil};
 use silk::transaction::Transaction;
 use silk::event::Event;
 use std::thread::sleep;
@@ -13,8 +13,8 @@ use std::sync::mpsc::SendError;
 
 fn create_log(hist: &Historian, seed: &Hash) -> Result<(), SendError<Event>> {
     sleep(Duration::from_millis(15));
-    let keypair = generate_keypair();
-    let tr = Transaction::new(&keypair, get_pubkey(&keypair), 42, *seed);
+    let keypair = KeyPair::new();
+    let tr = Transaction::new(&keypair, keypair.pubkey(), 42, *seed);
     let event0 = Event::Transaction(tr);
     hist.sender.send(event0)?;
     sleep(Duration::from_millis(10));

src/bin/mint.rs

@@ -0,0 +1,15 @@
+extern crate serde_json;
+extern crate silk;
+
+use silk::mint::Mint;
+use std::io;
+
+fn main() {
+    let mut input_text = String::new();
+    io::stdin().read_line(&mut input_text).unwrap();
+    let trimmed = input_text.trim();
+    let tokens = trimmed.parse::<i64>().unwrap();
+
+    let mint = Mint::new(tokens);
+    println!("{}", serde_json::to_string(&mint).unwrap());
+}

src/lib.rs

@@ -5,7 +5,7 @@ pub mod transaction;
 pub mod event;
 pub mod entry;
 pub mod log;
-pub mod genesis;
+pub mod mint;
 pub mod logger;
 pub mod historian;
 pub mod accountant;

src/log.rs

@@ -48,7 +48,7 @@ pub fn next_ticks(start_hash: &Hash, num_hashes: u64, len: usize) -> Vec<Entry>
 #[cfg(test)]
 mod tests {
     use super::*;
-    use signature::{generate_keypair, get_pubkey};
+    use signature::{KeyPair, KeyPairUtil};
     use transaction::Transaction;
     use hash::hash;
 
@@ -71,9 +71,9 @@ mod tests {
         let zero = Hash::default();
 
         // First, verify entries
-        let keypair = generate_keypair();
-        let tr0 = Transaction::new(&keypair, get_pubkey(&keypair), 0, zero);
-        let tr1 = Transaction::new(&keypair, get_pubkey(&keypair), 1, zero);
+        let keypair = KeyPair::new();
+        let tr0 = Transaction::new(&keypair, keypair.pubkey(), 0, zero);
+        let tr1 = Transaction::new(&keypair, keypair.pubkey(), 1, zero);
         let events = vec![Event::Transaction(tr0), Event::Transaction(tr1)];
         let mut entries = create_entries(&zero, events);
         assert!(verify_slice(&entries, &zero));

src/mint.rs

@@ -2,51 +2,45 @@
 
 use event::Event;
 use transaction::Transaction;
-use signature::{get_pubkey, PublicKey};
+use signature::{KeyPair, KeyPairUtil, PublicKey};
 use entry::Entry;
 use log::create_entries;
 use hash::{hash, Hash};
 use ring::rand::SystemRandom;
-use ring::signature::Ed25519KeyPair;
 use untrusted::Input;
 
 #[derive(Serialize, Deserialize, Debug)]
-pub struct Genesis {
+pub struct Mint {
     pub pkcs8: Vec<u8>,
     pub tokens: i64,
 }
 
-impl Genesis {
+impl Mint {
     pub fn new(tokens: i64) -> Self {
         let rnd = SystemRandom::new();
-        let pkcs8 = Ed25519KeyPair::generate_pkcs8(&rnd).unwrap().to_vec();
-        Genesis { pkcs8, tokens }
+        let pkcs8 = KeyPair::generate_pkcs8(&rnd).unwrap().to_vec();
+        Mint { pkcs8, tokens }
     }
 
-    pub fn get_seed(&self) -> Hash {
+    pub fn seed(&self) -> Hash {
         hash(&self.pkcs8)
     }
 
-    pub fn get_keypair(&self) -> Ed25519KeyPair {
-        Ed25519KeyPair::from_pkcs8(Input::from(&self.pkcs8)).unwrap()
+    pub fn keypair(&self) -> KeyPair {
+        KeyPair::from_pkcs8(Input::from(&self.pkcs8)).unwrap()
     }
 
-    pub fn get_pubkey(&self) -> PublicKey {
-        get_pubkey(&self.get_keypair())
+    pub fn pubkey(&self) -> PublicKey {
+        self.keypair().pubkey()
     }
 
     pub fn create_events(&self) -> Vec<Event> {
-        let tr = Transaction::new(
-            &self.get_keypair(),
-            self.get_pubkey(),
-            self.tokens,
-            self.get_seed(),
-        );
+        let tr = Transaction::new(&self.keypair(), self.pubkey(), self.tokens, self.seed());
         vec![Event::Tick, Event::Transaction(tr)]
     }
 
     pub fn create_entries(&self) -> Vec<Entry> {
-        create_entries(&self.get_seed(), self.create_events())
+        create_entries(&self.seed(), self.create_events())
     }
 }
 
@@ -57,7 +51,7 @@ mod tests {
 
     #[test]
     fn test_create_events() {
-        let mut events = Genesis::new(100).create_events().into_iter();
+        let mut events = Mint::new(100).create_events().into_iter();
         assert_eq!(events.next().unwrap(), Event::Tick);
         if let Event::Transaction(tr) = events.next().unwrap() {
             assert_eq!(tr.from, tr.to);
@@ -69,7 +63,7 @@ mod tests {
 
     #[test]
     fn test_verify_entries() {
-        let entries = Genesis::new(100).create_entries();
+        let entries = Mint::new(100).create_entries();
         assert!(verify_slice(&entries, &entries[0].id));
     }
 }

src/signature.rs

@@ -10,22 +10,34 @@ pub type KeyPair = Ed25519KeyPair;
 pub type PublicKey = GenericArray<u8, U32>;
 pub type Signature = GenericArray<u8, U64>;
 
-/// Return a new ED25519 keypair
-pub fn generate_keypair() -> KeyPair {
-    let rng = rand::SystemRandom::new();
-    let pkcs8_bytes = signature::Ed25519KeyPair::generate_pkcs8(&rng).unwrap();
-    signature::Ed25519KeyPair::from_pkcs8(untrusted::Input::from(&pkcs8_bytes)).unwrap()
+pub trait KeyPairUtil {
+    fn new() -> Self;
+    fn pubkey(&self) -> PublicKey;
 }
 
-/// Return the public key for the given keypair
-pub fn get_pubkey(keypair: &KeyPair) -> PublicKey {
-    GenericArray::clone_from_slice(keypair.public_key_bytes())
+impl KeyPairUtil for Ed25519KeyPair {
+    /// Return a new ED25519 keypair
+    fn new() -> Self {
+        let rng = rand::SystemRandom::new();
+        let pkcs8_bytes = signature::Ed25519KeyPair::generate_pkcs8(&rng).unwrap();
+        signature::Ed25519KeyPair::from_pkcs8(untrusted::Input::from(&pkcs8_bytes)).unwrap()
+    }
+
+    /// Return the public key for the given keypair
+    fn pubkey(&self) -> PublicKey {
+        GenericArray::clone_from_slice(self.public_key_bytes())
+    }
 }
 
-/// 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 {
-    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 trait SignatureUtil {
+    fn verify(&self, peer_public_key_bytes: &[u8], msg_bytes: &[u8]) -> bool;
+}
+
+impl SignatureUtil for GenericArray<u8, U64> {
+    fn verify(&self, peer_public_key_bytes: &[u8], msg_bytes: &[u8]) -> bool {
+        let peer_public_key = untrusted::Input::from(peer_public_key_bytes);
+        let msg = untrusted::Input::from(msg_bytes);
+        let sig = untrusted::Input::from(self);
+        signature::verify(&signature::ED25519, peer_public_key, msg, sig).is_ok()
+    }
 }

src/transaction.rs

@@ -1,6 +1,6 @@
 //! The `transaction` crate provides functionality for creating log transactions.
 
-use signature::{get_pubkey, verify_signature, KeyPair, PublicKey, Signature};
+use signature::{KeyPair, KeyPairUtil, PublicKey, Signature, SignatureUtil};
 use serde::Serialize;
 use bincode::serialize;
 use hash::Hash;
@@ -17,7 +17,7 @@ pub struct Transaction<T> {
 impl<T: Serialize> Transaction<T> {
     pub fn new(from_keypair: &KeyPair, to: PublicKey, asset: T, last_id: Hash) -> Self {
         let mut tr = Transaction {
-            from: get_pubkey(&from_keypair),
+            from: from_keypair.pubkey(),
             to,
             asset,
             last_id,
@@ -37,7 +37,7 @@ impl<T: Serialize> Transaction<T> {
     }
 
     pub fn verify(&self) -> bool {
-        verify_signature(&self.from, &self.get_sign_data(), &self.sig)
+        self.sig.verify(&self.from, &self.get_sign_data())
     }
 }
 
@@ -45,24 +45,23 @@ impl<T: Serialize> Transaction<T> {
 mod tests {
     use super::*;
     use bincode::{deserialize, serialize};
-    use signature::*;
     use hash::hash;
 
     #[test]
     fn test_claim() {
-        let keypair = generate_keypair();
+        let keypair = KeyPair::new();
         let asset = hash(b"hello, world");
         let zero = Hash::default();
-        let tr0 = Transaction::new(&keypair, get_pubkey(&keypair), asset, zero);
+        let tr0 = Transaction::new(&keypair, keypair.pubkey(), asset, zero);
         assert!(tr0.verify());
     }
 
     #[test]
     fn test_transfer() {
         let zero = Hash::default();
-        let keypair0 = generate_keypair();
-        let keypair1 = generate_keypair();
-        let pubkey1 = get_pubkey(&keypair1);
+        let keypair0 = KeyPair::new();
+        let keypair1 = KeyPair::new();
+        let pubkey1 = keypair1.pubkey();
         let asset = hash(b"hello, world");
         let tr0 = Transaction::new(&keypair0, pubkey1, asset, zero);
         assert!(tr0.verify());
@@ -85,8 +84,8 @@ mod tests {
     #[test]
     fn test_bad_event_signature() {
         let zero = Hash::default();
-        let keypair = generate_keypair();
-        let pubkey = get_pubkey(&keypair);
+        let keypair = KeyPair::new();
+        let pubkey = keypair.pubkey();
         let mut tr = Transaction::new(&keypair, pubkey, hash(b"hello, world"), zero);
         tr.sign(&keypair);
         tr.asset = hash(b"goodbye cruel world"); // <-- attack!
@@ -95,14 +94,14 @@ mod tests {
 
     #[test]
     fn test_hijack_attack() {
-        let keypair0 = generate_keypair();
-        let keypair1 = generate_keypair();
-        let thief_keypair = generate_keypair();
-        let pubkey1 = get_pubkey(&keypair1);
+        let keypair0 = KeyPair::new();
+        let keypair1 = KeyPair::new();
+        let thief_keypair = KeyPair::new();
+        let pubkey1 = keypair1.pubkey();
         let zero = Hash::default();
         let mut tr = Transaction::new(&keypair0, pubkey1, hash(b"hello, world"), zero);
         tr.sign(&keypair0);
-        tr.to = get_pubkey(&thief_keypair); // <-- attack!
+        tr.to = thief_keypair.pubkey(); // <-- attack!
         assert!(!tr.verify());
     }
 }