diff --git a/src/crypto/mod.rs b/src/crypto/mod.rs
index e879392..29dbb7b 100644
--- a/src/crypto/mod.rs
+++ b/src/crypto/mod.rs
@@ -104,7 +104,7 @@ impl Signature {
 }
 
 /// A secret key, or a secret key share.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SecretKey(Fr);
 
 impl Default for SecretKey {
diff --git a/src/crypto/poly.rs b/src/crypto/poly.rs
index b58ad01..f03dab6 100644
--- a/src/crypto/poly.rs
+++ b/src/crypto/poly.rs
@@ -390,8 +390,8 @@ impl BivarPoly {
     }
 }
 
-/// A commitment to a bivariate polynomial.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+/// A commitment to a symmetric bivariate polynomial.
+#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq)]
 pub struct BivarCommitment {
     /// The polynomial's degree in each of the two variables.
     degree: usize,
diff --git a/src/honey_badger.rs b/src/honey_badger.rs
index 0b0ee05..0ad23e8 100644
--- a/src/honey_badger.rs
+++ b/src/honey_badger.rs
@@ -3,12 +3,11 @@ use std::collections::{BTreeMap, BTreeSet, HashSet, VecDeque};
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::rc::Rc;
-use std::{cmp, iter};
+use std::{cmp, iter, mem};
 
 use bincode;
 use rand;
-use serde::de::DeserializeOwned;
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 
 use common_subset::{self, CommonSubset};
 use crypto::{Ciphertext, DecryptionShare};
@@ -63,7 +62,7 @@ pub struct HoneyBadger<Tx, NodeUid> {
 
 impl<Tx, NodeUid> DistAlgorithm for HoneyBadger<Tx, NodeUid>
 where
-    Tx: Eq + Hash + Serialize + DeserializeOwned + Debug,
+    Tx: Serialize + for<'r> Deserialize<'r> + Debug + Hash + Eq,
     NodeUid: Ord + Clone + Debug,
 {
     type NodeUid = NodeUid;
@@ -119,7 +118,7 @@ where
 // TODO: Use a threshold encryption scheme to encrypt the proposed transactions.
 impl<Tx, NodeUid> HoneyBadger<Tx, NodeUid>
 where
-    Tx: Eq + Hash + Serialize + DeserializeOwned + Debug,
+    Tx: Serialize + for<'r> Deserialize<'r> + Debug + Hash + Eq,
     NodeUid: Ord + Clone + Debug,
 {
     /// Returns a new Honey Badger instance with the given parameters, starting at epoch `0`.
@@ -156,6 +155,11 @@ where
         Ok(())
     }
 
+    /// Empties and returns the transaction buffer.
+    pub fn drain_buffer(&mut self) -> Vec<Tx> {
+        mem::replace(&mut self.buffer, Vec::new())
+    }
+
     /// Proposes a new batch in the current epoch.
     fn propose(&mut self) -> HoneyBadgerResult<()> {
         let proposal = self.choose_transactions()?;
diff --git a/src/messaging.rs b/src/messaging.rs
index d10ac34..f243725 100644
--- a/src/messaging.rs
+++ b/src/messaging.rs
@@ -136,7 +136,7 @@ impl<'a, D: DistAlgorithm + 'a> Iterator for OutputIter<'a, D> {
 /// use this construction to zero out the section of heap memory that is
 /// allocated for `secret_key` when the corresponding instance of
 /// `NetworkInfo` goes out of scope.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct NetworkInfo<NodeUid> {
     our_uid: NodeUid,
     all_uids: BTreeSet<NodeUid>,
diff --git a/src/sync_key_gen.rs b/src/sync_key_gen.rs
index aac0c57..67dbc06 100644
--- a/src/sync_key_gen.rs
+++ b/src/sync_key_gen.rs
@@ -34,25 +34,27 @@
 
 use std::collections::btree_map::Entry;
 use std::collections::{BTreeMap, BTreeSet};
+use std::fmt::Debug;
+
+use bincode;
+use clear_on_drop::ClearOnDrop;
+use pairing::bls12_381::{Fr, G1Affine};
+use pairing::{CurveAffine, Field};
+use rand::OsRng;
 
 use crypto::poly::{BivarCommitment, BivarPoly, Poly};
 use crypto::serde_impl::field_vec::FieldWrap;
 use crypto::{Ciphertext, PublicKey, PublicKeySet, SecretKey};
 
-use bincode;
-use pairing::bls12_381::{Fr, G1Affine};
-use pairing::{CurveAffine, Field};
-use rand::OsRng;
-
 // TODO: No need to send our own row and value to ourselves.
 
 /// A commitment to a bivariate polynomial, and for each node, an encrypted row of values.
-#[derive(Deserialize, Serialize, Debug, Clone)]
+#[derive(Deserialize, Serialize, Debug, Clone, Hash, Eq, PartialEq)]
 pub struct Propose(BivarCommitment, Vec<Ciphertext>);
 
 /// A confirmation that we have received a node's proposal and verified our row against the
 /// commitment. For each node, it contains one encrypted value of our row.
-#[derive(Deserialize, Serialize, Debug, Clone)]
+#[derive(Deserialize, Serialize, Debug, Clone, Hash, Eq, PartialEq)]
 pub struct Accept(u64, Vec<Ciphertext>);
 
 /// The information needed to track a single proposer's secret sharing process.
@@ -84,33 +86,37 @@ impl ProposalState {
 /// A synchronous algorithm for dealerless distributed key generation.
 ///
 /// It requires that all nodes handle all messages in the exact same order.
-pub struct SyncKeyGen {
+pub struct SyncKeyGen<NodeUid> {
     /// Our node index.
     our_idx: u64,
     /// Our secret key.
     sec_key: SecretKey,
     /// The public keys of all nodes, by node index.
-    pub_keys: Vec<PublicKey>,
+    pub_keys: BTreeMap<NodeUid, PublicKey>,
     /// Proposed bivariate polynomial.
     proposals: BTreeMap<u64, ProposalState>,
     /// The degree of the generated polynomial.
     threshold: usize,
 }
 
-impl SyncKeyGen {
+impl<NodeUid: Ord + Debug> SyncKeyGen<NodeUid> {
     /// Creates a new `SyncKeyGen` instance, together with the `Propose` message that should be
     /// broadcast.
     pub fn new(
-        our_idx: u64,
+        our_uid: &NodeUid,
         sec_key: SecretKey,
-        pub_keys: Vec<PublicKey>,
+        pub_keys: BTreeMap<NodeUid, PublicKey>,
         threshold: usize,
-    ) -> (SyncKeyGen, Propose) {
+    ) -> (SyncKeyGen<NodeUid>, Propose) {
+        let our_idx = pub_keys
+            .keys()
+            .position(|uid| uid == our_uid)
+            .expect("missing pub key for own ID") as u64;
         let mut rng = OsRng::new().expect("OS random number generator");
         let our_proposal = BivarPoly::random(threshold, &mut rng);
         let commit = our_proposal.commitment();
         let rows: Vec<_> = pub_keys
-            .iter()
+            .values()
             .enumerate()
             .map(|(i, pk)| {
                 let row = our_proposal.row(i as u64 + 1);
@@ -131,9 +137,16 @@ impl SyncKeyGen {
     /// Handles a `Propose` message. If it is valid, returns an `Accept` message to be broadcast.
     pub fn handle_propose(
         &mut self,
-        sender_idx: u64,
+        sender_id: &NodeUid,
         Propose(commit, rows): Propose,
     ) -> Option<Accept> {
+        let sender_idx =
+            if let Some(sender_idx) = self.pub_keys.keys().position(|uid| uid == sender_id) {
+                sender_idx as u64
+            } else {
+                debug!("Unknown sender {:?}", sender_id);
+                return None;
+            };
         let commit_row = commit.row(self.our_idx + 1);
         match self.proposals.entry(sender_idx) {
             Entry::Occupied(_) => return None, // Ignore multiple proposals.
@@ -150,7 +163,7 @@ impl SyncKeyGen {
         // The row is valid: now encrypt one value for each node.
         let values = self
             .pub_keys
-            .iter()
+            .values()
             .enumerate()
             .map(|(idx, pk)| {
                 let val = row.evaluate(idx as u64 + 1);
@@ -163,7 +176,14 @@ impl SyncKeyGen {
     }
 
     /// Handles an `Accept` message.
-    pub fn handle_accept(&mut self, sender_idx: u64, accept: Accept) {
+    pub fn handle_accept(&mut self, sender_id: &NodeUid, accept: Accept) {
+        let sender_idx =
+            if let Some(sender_idx) = self.pub_keys.keys().position(|uid| uid == sender_id) {
+                sender_idx as u64
+            } else {
+                debug!("Unknown sender {:?}", sender_id);
+                return;
+            };
         if let Err(err) = self.handle_accept_or_err(sender_idx, accept) {
             debug!("Invalid accept from node {}: {}", sender_idx, err);
         }
@@ -194,7 +214,7 @@ impl SyncKeyGen {
     ///
     /// These are only secure if `is_ready` returned `true`. Otherwise it is not guaranteed that
     /// none of the nodes knows the secret master key.
-    pub fn generate(&self) -> (PublicKeySet, SecretKey) {
+    pub fn generate(&self) -> (PublicKeySet, ClearOnDrop<Box<SecretKey>>) {
         let mut pk_commit = Poly::zero().commitment();
         let mut sk_val = Fr::zero();
         for proposal in self
@@ -206,7 +226,8 @@ impl SyncKeyGen {
             let row: Poly = Poly::interpolate(proposal.values.iter().take(self.threshold + 1));
             sk_val.add_assign(&row.evaluate(0));
         }
-        (pk_commit.into(), SecretKey::from_value(sk_val))
+        let sk = ClearOnDrop::new(Box::new(SecretKey::from_value(sk_val)));
+        (pk_commit.into(), sk)
     }
 
     /// Handles an `Accept` message or returns an error string.
diff --git a/tests/agreement.rs b/tests/agreement.rs
index de4b047..198a8de 100644
--- a/tests/agreement.rs
+++ b/tests/agreement.rs
@@ -19,6 +19,8 @@ extern crate hbbft;
 extern crate log;
 extern crate pairing;
 extern crate rand;
+#[macro_use]
+extern crate serde_derive;
 
 mod network;
 
diff --git a/tests/broadcast.rs b/tests/broadcast.rs
index 597900a..a4c47cd 100644
--- a/tests/broadcast.rs
+++ b/tests/broadcast.rs
@@ -6,6 +6,8 @@ extern crate log;
 extern crate env_logger;
 extern crate pairing;
 extern crate rand;
+#[macro_use]
+extern crate serde_derive;
 
 mod network;
 
diff --git a/tests/common_coin.rs b/tests/common_coin.rs
index cd62c27..9e26daf 100644
--- a/tests/common_coin.rs
+++ b/tests/common_coin.rs
@@ -6,6 +6,8 @@ extern crate hbbft;
 extern crate log;
 extern crate pairing;
 extern crate rand;
+#[macro_use]
+extern crate serde_derive;
 
 mod network;
 
diff --git a/tests/common_subset.rs b/tests/common_subset.rs
index 84dbbcc..37be109 100644
--- a/tests/common_subset.rs
+++ b/tests/common_subset.rs
@@ -6,6 +6,8 @@ extern crate hbbft;
 extern crate log;
 extern crate pairing;
 extern crate rand;
+#[macro_use]
+extern crate serde_derive;
 
 mod network;
 
diff --git a/tests/honey_badger.rs b/tests/honey_badger.rs
index e22edd7..f2e883c 100644
--- a/tests/honey_badger.rs
+++ b/tests/honey_badger.rs
@@ -6,6 +6,8 @@ extern crate log;
 extern crate env_logger;
 extern crate pairing;
 extern crate rand;
+#[macro_use]
+extern crate serde_derive;
 
 mod network;
 
diff --git a/tests/network/mod.rs b/tests/network/mod.rs
index 71d5716..414cdfb 100644
--- a/tests/network/mod.rs
+++ b/tests/network/mod.rs
@@ -9,7 +9,7 @@ use hbbft::crypto::SecretKeySet;
 use hbbft::messaging::{DistAlgorithm, NetworkInfo, Target, TargetedMessage};
 
 /// A node identifier. In the tests, nodes are simply numbered.
-#[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy)]
+#[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, Serialize, Deserialize)]
 pub struct NodeUid(pub usize);
 
 /// A "node" running an instance of the algorithm `D`.
diff --git a/tests/sync_key_gen.rs b/tests/sync_key_gen.rs
index 7a1a2c6..6b6f46f 100644
--- a/tests/sync_key_gen.rs
+++ b/tests/sync_key_gen.rs
@@ -15,16 +15,19 @@ fn test_sync_key_gen_with(threshold: usize, node_num: usize) {
 
     // Generate individual key pairs for encryption. These are not suitable for threshold schemes.
     let sec_keys: Vec<SecretKey> = (0..node_num).map(|_| SecretKey::new(&mut rng)).collect();
-    let pub_keys: Vec<PublicKey> = sec_keys.iter().map(|sk| sk.public_key()).collect();
+    let pub_keys: BTreeMap<usize, PublicKey> = sec_keys
+        .iter()
+        .map(|sk| sk.public_key())
+        .enumerate()
+        .collect();
 
     // Create the `SyncKeyGen` instances and initial proposals.
     let mut nodes = Vec::new();
     let proposals: Vec<_> = sec_keys
         .into_iter()
         .enumerate()
-        .map(|(idx, sk)| {
-            let (sync_key_gen, proposal) =
-                SyncKeyGen::new(idx as u64, sk, pub_keys.clone(), threshold);
+        .map(|(id, sk)| {
+            let (sync_key_gen, proposal) = SyncKeyGen::new(&id, sk, pub_keys.clone(), threshold);
             nodes.push(sync_key_gen);
             proposal
         })
@@ -32,23 +35,23 @@ fn test_sync_key_gen_with(threshold: usize, node_num: usize) {
 
     // Handle the first `threshold + 1` proposals. Those should suffice for key generation.
     let mut accepts = Vec::new();
-    for (sender_idx, proposal) in proposals[..=threshold].iter().enumerate() {
-        for (node_idx, node) in nodes.iter_mut().enumerate() {
+    for (sender_id, proposal) in proposals[..=threshold].iter().enumerate() {
+        for (node_id, node) in nodes.iter_mut().enumerate() {
             let accept = node
-                .handle_propose(sender_idx as u64, proposal.clone())
+                .handle_propose(&sender_id, proposal.clone())
                 .expect("valid proposal");
             // Only the first `threshold + 1` manage to commit their `Accept`s.
-            if node_idx <= 2 * threshold {
-                accepts.push((node_idx, accept));
+            if node_id <= 2 * threshold {
+                accepts.push((node_id, accept));
             }
         }
     }
 
     // Handle the `Accept`s from `2 * threshold + 1` nodes.
-    for (sender_idx, accept) in accepts {
+    for (sender_id, accept) in accepts {
         for node in &mut nodes {
             assert!(!node.is_ready()); // Not enough `Accept`s yet.
-            node.handle_accept(sender_idx as u64, accept.clone());
+            node.handle_accept(&sender_id, accept.clone());
         }
     }