A0-4152: Global consensus threshold and other crypto improvements

README.md

@@ -60,7 +60,7 @@ More details are available [in the book][reference-link-implementation-details].
 - Import AlephBFT in your crate
   ```toml
   [dependencies]
-  aleph-bft = "^0.34"
+  aleph-bft = "^0.35"
   ```
 - The main entry point is the `run_session` function, which returns a Future that runs the
   consensus algorithm.

consensus/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "aleph-bft"
-version = "0.34.1"
+version = "0.35.0"
 edition = "2021"
 authors = ["Cardinal Cryptography"]
 categories = ["algorithms", "data-structures", "cryptography", "database"]
@@ -13,8 +13,8 @@ readme = "../README.md"
 description = "AlephBFT is an asynchronous and Byzantine fault tolerant consensus protocol aimed at ordering arbitrary messages (transactions). It has been designed to continuously operate even in the harshest conditions: with no bounds on message-delivery delays and in the presence of malicious actors. This makes it an excellent fit for blockchain-related applications."
 
 [dependencies]
-aleph-bft-rmc = { path = "../rmc", version = "0.11" }
-aleph-bft-types = { path = "../types", version = "0.11" }
+aleph-bft-rmc = { path = "../rmc", version = "0.12" }
+aleph-bft-types = { path = "../types", version = "0.12" }
 anyhow = "1.0"
 async-trait = "0.1"
 codec = { package = "parity-scale-codec", version = "3.0", default-features = false, features = ["derive"] }

consensus/src/backup/loader.rs

@@ -246,7 +246,7 @@ mod tests {
     use crate::{
         backup::BackupLoader,
         units::{
-            create_units, creator_set, preunit_to_unchecked_signed_unit, preunit_to_unit,
+            create_preunits, creator_set, preunit_to_unchecked_signed_unit, preunit_to_unit,
             UncheckedSignedUnit as GenericUncheckedSignedUnit,
         },
         NodeCount, NodeIndex, Round, SessionId,
@@ -273,7 +273,7 @@ mod tests {
         let mut units_per_round = Vec::with_capacity(rounds);
 
         for round in 0..rounds {
-            let pre_units = create_units(creators.iter(), round as Round);
+            let pre_units = create_preunits(creators.iter(), round as Round);
 
             let units: Vec<_> = pre_units
                 .iter()

consensus/src/creation/creator.rs

@@ -41,9 +41,7 @@ impl<H: Hasher> UnitsCollector<H> {
         &self,
         node_id: NodeIndex,
     ) -> Result<&NodeMap<H::Hash>, ConstraintError> {
-        let threshold = (self.candidates.size() * 2) / 3 + NodeCount(1);
-
-        if self.n_candidates < threshold {
+        if self.n_candidates < self.candidates.size().consensus_threshold() {
             return Err(ConstraintError::NotEnoughParents);
         }
         if self.candidates.get(node_id).is_none() {
@@ -95,7 +93,7 @@ impl<H: Hasher> Creator<H> {
         &mut self.round_collectors[round_ix]
     }
 
-    /// To create a new unit, we need to have at least floor(2*N/3) + 1 parents available in previous round.
+    /// To create a new unit, we need to have at least the consensus threshold of parents available in previous round.
     /// Additionally, our unit from previous round must be available.
     pub fn create_unit(&self, round: Round) -> Result<(PreUnit<H>, Vec<H::Hash>)> {
         if round == 0 {
@@ -124,7 +122,7 @@ mod tests {
     use super::{Creator as GenericCreator, UnitsCollector};
     use crate::{
         creation::creator::ConstraintError,
-        units::{create_units, creator_set, preunit_to_unit},
+        units::{create_preunits, creator_set, preunit_to_unit},
         NodeCount, NodeIndex,
     };
     use aleph_bft_mock::Hasher64;
@@ -149,7 +147,7 @@ mod tests {
     fn creates_unit_with_all_parents() {
         let n_members = NodeCount(7);
         let mut creators = creator_set(n_members);
-        let new_units = create_units(creators.iter(), 0);
+        let new_units = create_preunits(creators.iter(), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -167,9 +165,9 @@ mod tests {
     }
 
     fn create_unit_with_minimal_parents(n_members: NodeCount) {
-        let n_parents = (n_members.0 * 2) / 3 + 1;
+        let n_parents = n_members.consensus_threshold().0;
         let mut creators = creator_set(n_members);
-        let new_units = create_units(creators.iter().take(n_parents), 0);
+        let new_units = create_preunits(creators.iter().take(n_parents), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -207,9 +205,9 @@ mod tests {
     }
 
     fn dont_create_unit_below_parents_threshold(n_members: NodeCount) {
-        let n_parents = (n_members.0 * 2) / 3;
+        let n_parents = n_members.consensus_threshold() - NodeCount(1);
         let mut creators = creator_set(n_members);
-        let new_units = create_units(creators.iter().take(n_parents), 0);
+        let new_units = create_preunits(creators.iter().take(n_parents.0), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -247,7 +245,7 @@ mod tests {
         let mut creators = creator_set(n_members);
         let mut expected_hashes_per_round = Vec::new();
         for round in 0..2 {
-            let new_units = create_units(creators.iter().skip(1), round);
+            let new_units = create_preunits(creators.iter().skip(1), round);
             let new_units: Vec<_> = new_units
                 .into_iter()
                 .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -284,7 +282,7 @@ mod tests {
     fn cannot_create_unit_without_predecessor() {
         let n_members = NodeCount(7);
         let mut creators = creator_set(n_members);
-        let new_units = create_units(creators.iter().skip(1), 0);
+        let new_units = create_preunits(creators.iter().skip(1), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -299,7 +297,7 @@ mod tests {
     fn units_collector_successfully_computes_parents() {
         let n_members = NodeCount(4);
         let creators = creator_set(n_members);
-        let new_units = create_units(creators.iter(), 0);
+        let new_units = create_preunits(creators.iter(), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -324,7 +322,7 @@ mod tests {
     fn units_collector_returns_err_when_not_enough_parents() {
         let n_members = NodeCount(4);
         let creators = creator_set(n_members);
-        let new_units = create_units(creators.iter().take(2), 0);
+        let new_units = create_preunits(creators.iter().take(2), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))
@@ -346,7 +344,7 @@ mod tests {
     fn units_collector_returns_err_when_missing_own_parent() {
         let n_members = NodeCount(4);
         let creators = creator_set(n_members);
-        let new_units = create_units(creators.iter().take(3), 0);
+        let new_units = create_preunits(creators.iter().take(3), 0);
         let new_units: Vec<_> = new_units
             .into_iter()
             .map(|(pu, _)| preunit_to_unit(pu, 0))

consensus/src/extension/election.rs

@@ -66,7 +66,7 @@ impl<H: Hasher> CandidateElection<H> {
         relative_round: Round,
     ) -> Result<bool, CandidateOutcome<H>> {
         use CandidateOutcome::*;
-        let threshold = (parents.size() * 2) / 3 + NodeCount(1);
+        let threshold = parents.size().consensus_threshold();
         // Gather parents' votes.
         let (votes_for, votes_against) = self.parent_votes(parents)?;
         assert!(votes_for + votes_against >= threshold);

consensus/src/reconstruction/dag.rs

@@ -123,10 +123,10 @@ impl<H: Hasher> Dag<H> {
 mod test {
     use crate::{
         reconstruction::{dag::Dag, ReconstructedUnit},
-        units::tests::{random_full_parent_units_up_to, TestFullUnit},
+        units::{random_full_parent_units_up_to, FullUnit},
         Hasher, NodeCount, NodeIndex, NodeMap,
     };
-    use aleph_bft_mock::Hasher64;
+    use aleph_bft_mock::{Data, Hasher64};
     use std::collections::HashSet;
 
     fn full_parents_to_map(
@@ -141,11 +141,13 @@ mod test {
 
     // silly clippy, the map below doesn't work with &[..]
     #[allow(clippy::ptr_arg)]
-    fn unit_hashes(units: &Vec<TestFullUnit>) -> Vec<<Hasher64 as Hasher>::Hash> {
+    fn unit_hashes(units: &Vec<FullUnit<Hasher64, Data>>) -> Vec<<Hasher64 as Hasher>::Hash> {
         units.iter().map(|unit| unit.hash()).collect()
     }
 
-    fn reconstructed(dag: Vec<Vec<TestFullUnit>>) -> Vec<Vec<ReconstructedUnit<Hasher64>>> {
+    fn reconstructed(
+        dag: Vec<Vec<FullUnit<Hasher64, Data>>>,
+    ) -> Vec<Vec<ReconstructedUnit<Hasher64>>> {
         let hashes: Vec<_> = dag.iter().map(unit_hashes).collect();
         let initial_units: Vec<_> = dag
             .get(0)
@@ -171,7 +173,7 @@ mod test {
     #[test]
     fn reconstructs_initial_units() {
         let mut dag = Dag::new();
-        for unit in reconstructed(random_full_parent_units_up_to(0, NodeCount(4)))
+        for unit in reconstructed(random_full_parent_units_up_to(0, NodeCount(4), 43))
             .pop()
             .expect("we have initial units")
         {
@@ -183,7 +185,7 @@ mod test {
     #[test]
     fn reconstructs_units_in_order() {
         let mut dag = Dag::new();
-        for units in reconstructed(random_full_parent_units_up_to(7000, NodeCount(4))) {
+        for units in reconstructed(random_full_parent_units_up_to(7000, NodeCount(4), 43)) {
             for unit in units {
                 let reconstructed = dag.add_unit(unit.clone());
                 assert_eq!(reconstructed, vec![unit]);
@@ -193,7 +195,7 @@ mod test {
 
     #[test]
     fn reconstructs_units_in_reverse_order() {
-        let full_unit_dag = random_full_parent_units_up_to(7000, NodeCount(4));
+        let full_unit_dag = random_full_parent_units_up_to(7000, NodeCount(4), 43);
         let mut hash_batches: Vec<_> = full_unit_dag
             .iter()
             .map(unit_hashes)

consensus/src/reconstruction/parents.rs

@@ -291,17 +291,14 @@ mod test {
             parents::{Reconstruction, Request},
             ReconstructedUnit,
         },
-        units::{
-            tests::{random_full_parent_units_up_to, TestFullUnit},
-            UnitCoord,
-        },
+        units::{random_full_parent_units_up_to, UnitCoord},
         NodeCount, NodeIndex,
     };
 
     #[test]
     fn reconstructs_initial_units() {
         let mut reconstruction = Reconstruction::new();
-        for unit in &random_full_parent_units_up_to(0, NodeCount(4))[0] {
+        for unit in &random_full_parent_units_up_to(0, NodeCount(4), 43)[0] {
             let unit = unit.unit();
             let (mut reconstructed_units, requests) = reconstruction.add_unit(unit.clone()).into();
             assert!(requests.is_empty());
@@ -315,7 +312,7 @@ mod test {
     #[test]
     fn reconstructs_units_coming_in_order() {
         let mut reconstruction = Reconstruction::new();
-        let dag = random_full_parent_units_up_to(7, NodeCount(4));
+        let dag = random_full_parent_units_up_to(7, NodeCount(4), 43);
         for units in &dag {
             for unit in units {
                 let unit = unit.unit();
@@ -332,7 +329,7 @@ mod test {
                     }
                     round => {
                         assert_eq!(reconstructed_unit.parents().item_count(), 4);
-                        let parents: &Vec<TestFullUnit> = dag
+                        let parents = dag
                             .get((round - 1) as usize)
                             .expect("the parents are there");
                         for (parent, reconstructed_parent) in
@@ -349,7 +346,7 @@ mod test {
     #[test]
     fn requests_all_parents() {
         let mut reconstruction = Reconstruction::new();
-        let dag = random_full_parent_units_up_to(1, NodeCount(4));
+        let dag = random_full_parent_units_up_to(1, NodeCount(4), 43);
         let unit = dag
             .get(1)
             .expect("just created")
@@ -364,7 +361,7 @@ mod test {
     #[test]
     fn requests_single_parent() {
         let mut reconstruction = Reconstruction::new();
-        let dag = random_full_parent_units_up_to(1, NodeCount(4));
+        let dag = random_full_parent_units_up_to(1, NodeCount(4), 43);
         for unit in dag.get(0).expect("just created").iter().skip(1) {
             let unit = unit.unit();
             reconstruction.add_unit(unit.clone());
@@ -387,7 +384,7 @@ mod test {
     #[test]
     fn reconstructs_units_coming_in_reverse_order() {
         let mut reconstruction = Reconstruction::new();
-        let mut dag = random_full_parent_units_up_to(7, NodeCount(4));
+        let mut dag = random_full_parent_units_up_to(7, NodeCount(4), 43);
         dag.reverse();
         for unit in dag.get(0).expect("we have the top units") {
             let unit = unit.unit();
@@ -414,12 +411,12 @@ mod test {
     #[test]
     fn handles_bad_hash() {
         let mut reconstruction = Reconstruction::new();
-        let dag = random_full_parent_units_up_to(0, NodeCount(4));
+        let dag = random_full_parent_units_up_to(0, NodeCount(4), 43);
         for unit in dag.get(0).expect("just created") {
             let unit = unit.unit();
             reconstruction.add_unit(unit.clone());
         }
-        let other_dag = random_full_parent_units_up_to(1, NodeCount(4));
+        let other_dag = random_full_parent_units_up_to(1, NodeCount(4), 43);
         let unit = other_dag
             .get(1)
             .expect("just created")