Merge pull request #2160 from subspace/pos-tweaks

PoS tweaks

crates/subspace-core-primitives/src/lib.rs

@@ -169,29 +169,6 @@ impl PosSeed {
     pub const SIZE: usize = 32;
 }
 
-/// Proof of space quality.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Deref)]
-pub struct PosQualityBytes([u8; Self::SIZE]);
-
-impl From<[u8; PosQualityBytes::SIZE]> for PosQualityBytes {
-    #[inline]
-    fn from(value: [u8; Self::SIZE]) -> Self {
-        Self(value)
-    }
-}
-
-impl From<PosQualityBytes> for [u8; PosQualityBytes::SIZE] {
-    #[inline]
-    fn from(value: PosQualityBytes) -> Self {
-        value.0
-    }
-}
-
-impl PosQualityBytes {
-    /// Size of proof of space quality in bytes.
-    pub const SIZE: usize = 32;
-}
-
 /// Proof of space proof bytes.
 #[derive(
     Debug, Copy, Clone, Eq, PartialEq, Deref, DerefMut, Encode, Decode, TypeInfo, MaxEncodedLen,

crates/subspace-farmer-components/src/plotting.rs

@@ -24,7 +24,7 @@ use subspace_core_primitives::{
     SectorId, SectorIndex,
 };
 use subspace_erasure_coding::ErasureCoding;
-use subspace_proof_of_space::{Quality, Table, TableGenerator};
+use subspace_proof_of_space::{Table, TableGenerator};
 use thiserror::Error;
 use tokio::sync::Semaphore;
 use tokio::task::yield_now;
@@ -353,11 +353,9 @@ where
                     .interleave(&parity_record_chunks),
             )
             .map(|(s_bucket, record_chunk)| {
-                let quality = pos_table.find_quality(s_bucket.into())?;
+                let proof = pos_table.find_proof(s_bucket.into())?;
 
-                Some(
-                    Simd::from(record_chunk.to_bytes()) ^ Simd::from(quality.create_proof().hash()),
-                )
+                Some(Simd::from(record_chunk.to_bytes()) ^ Simd::from(proof.hash()))
             })
             .collect_into_vec(&mut chunks_scratch);
         let num_successfully_encoded_chunks = chunks_scratch

crates/subspace-farmer-components/src/proving.rs

@@ -18,7 +18,7 @@ use subspace_core_primitives::{
     RecordWitness, SBucket, SectorId, Solution, SolutionRange,
 };
 use subspace_erasure_coding::ErasureCoding;
-use subspace_proof_of_space::{Quality, Table};
+use subspace_proof_of_space::Table;
 use thiserror::Error;
 
 /// Solutions that can be proven if necessary.
@@ -440,13 +440,9 @@ where
             );
             let record_metadata = record_metadata_fut.await?;
 
-            let proof_of_space = pos_table
-                .find_quality(state.s_bucket.into())
-                .expect(
-                    "Quality exists for this s-bucket, otherwise it wouldn't be a winning \
-                        chunk; qed",
-                )
-                .create_proof();
+            let proof_of_space = pos_table.find_proof(state.s_bucket.into()).expect(
+                "Quality exists for this s-bucket, otherwise it wouldn't be a winning chunk; qed",
+            );
 
             let chunk_witness = state
                 .kzg

crates/subspace-farmer-components/src/reading.rs

@@ -15,7 +15,7 @@ use subspace_core_primitives::{
     Piece, PieceOffset, Record, RecordCommitment, RecordWitness, SBucket, SectorId,
 };
 use subspace_erasure_coding::ErasureCoding;
-use subspace_proof_of_space::{Quality, Table, TableGenerator};
+use subspace_proof_of_space::{Table, TableGenerator};
 use thiserror::Error;
 use tracing::debug;
 
@@ -148,13 +148,12 @@ where
 
                     // Decode chunk if necessary
                     if encoded_chunk_used {
-                        let quality = pos_table.find_quality(s_bucket.into()).expect(
-                            "encoded_chunk_used implies quality exists for this chunk; qed",
-                        );
+                        let proof = pos_table
+                            .find_proof(s_bucket.into())
+                            .expect("encoded_chunk_used implies proof exists for this chunk; qed");
 
-                        record_chunk = Simd::to_array(
-                            Simd::from(record_chunk) ^ Simd::from(quality.create_proof().hash()),
-                        );
+                        record_chunk =
+                            Simd::to_array(Simd::from(record_chunk) ^ Simd::from(proof.hash()));
                     }
 
                     maybe_record_chunk.replace(Scalar::try_from(record_chunk).map_err(
@@ -194,12 +193,12 @@ where
 
                         // Decode chunk if necessary
                         if encoded_chunk_used {
-                            let quality = pos_table.find_quality(s_bucket.into()).expect(
-                                "encoded_chunk_used implies quality exists for this chunk; qed",
+                            let proof = pos_table.find_proof(s_bucket.into()).expect(
+                                "encoded_chunk_used implies proof exists for this chunk; qed",
                             );
 
                             record_chunk = Simd::to_array(
-                                Simd::from(record_chunk) ^ Simd::from(quality.create_proof().hash()),
+                                Simd::from(record_chunk) ^ Simd::from(proof.hash()),
                             );
                         }
 

crates/subspace-proof-of-space/benches/pos.rs

@@ -4,7 +4,7 @@ use criterion::{black_box, criterion_group, criterion_main, Criterion};
 #[cfg(feature = "parallel")]
 use rayon::ThreadPoolBuilder;
 use subspace_core_primitives::PosSeed;
-use subspace_proof_of_space::{Quality, Table, TableGenerator};
+use subspace_proof_of_space::{Table, TableGenerator};
 
 fn pos_bench<PosTable>(
     c: &mut Criterion,
@@ -49,37 +49,31 @@ fn pos_bench<PosTable>(
 
     let table = generator_instance.generate(&seed);
 
-    group.bench_function("quality/no-solution", |b| {
+    group.bench_function("proof/missing", |b| {
         b.iter(|| {
             assert!(table
-                .find_quality(black_box(challenge_index_without_solution))
+                .find_proof(black_box(challenge_index_without_solution))
                 .is_none());
         });
     });
 
-    group.bench_function("quality/solution", |b| {
+    group.bench_function("proof/present", |b| {
         b.iter(|| {
             assert!(table
-                .find_quality(black_box(challenge_index_with_solution))
+                .find_proof(black_box(challenge_index_with_solution))
                 .is_some());
         });
     });
 
-    let quality = table.find_quality(challenge_index_with_solution).unwrap();
-
-    group.bench_function("proof", |b| {
-        b.iter(|| {
-            quality.create_proof();
-        });
-    });
-
-    let proof = quality.create_proof();
+    let proof = table.find_proof(challenge_index_with_solution).unwrap();
 
     group.bench_function("verification", |b| {
         b.iter(|| {
-            assert!(
-                PosTable::is_proof_valid(&seed, challenge_index_with_solution, &proof).is_some()
-            );
+            assert!(PosTable::is_proof_valid(
+                &seed,
+                challenge_index_with_solution,
+                &proof
+            ));
         });
     });
     group.finish();

crates/subspace-proof-of-space/src/chia.rs

@@ -1,36 +1,11 @@
 //! Chia proof of space implementation
 use crate::chiapos::{Tables, TablesCache};
-use crate::{PosTableType, Quality, Table, TableGenerator};
+use crate::{PosTableType, Table, TableGenerator};
 use core::mem;
-use subspace_core_primitives::{PosProof, PosQualityBytes, PosSeed};
+use subspace_core_primitives::{PosProof, PosSeed};
 
 const K: u8 = 20;
 
-/// Abstraction that represents quality of the solution in the table.
-///
-/// Chia implementation.
-#[derive(Debug)]
-#[must_use]
-pub struct ChiaQuality<'a> {
-    bytes: PosQualityBytes,
-    challenge: [u8; 32],
-    tables: &'a Tables<K>,
-}
-
-impl<'a> Quality for ChiaQuality<'a> {
-    fn to_bytes(&self) -> PosQualityBytes {
-        self.bytes
-    }
-
-    fn create_proof(&self) -> PosProof {
-        self.tables
-            .find_proof(&self.challenge)
-            .next()
-            .map(PosProof::from)
-            .expect("Proof always exists if quality exists; qed")
-    }
-}
-
 /// Subspace proof of space table generator.
 ///
 /// Chia implementation.
@@ -66,8 +41,6 @@ impl Table for ChiaTable {
     const TABLE_TYPE: PosTableType = PosTableType::Chia;
     type Generator = ChiaTableGenerator;
 
-    type Quality<'a> = ChiaQuality<'a>;
-
     fn generate(seed: &PosSeed) -> ChiaTable {
         Self {
             tables: Tables::<K>::create_simple((*seed).into()),
@@ -81,25 +54,22 @@ impl Table for ChiaTable {
         }
     }
 
-    fn find_quality(&self, challenge_index: u32) -> Option<Self::Quality<'_>> {
+    fn find_proof(&self, challenge_index: u32) -> Option<PosProof> {
         let mut challenge = [0; 32];
         challenge[..mem::size_of::<u32>()].copy_from_slice(&challenge_index.to_le_bytes());
-        let maybe_quality = self.tables.find_quality(&challenge).next();
-        maybe_quality.map(|quality| ChiaQuality {
-            bytes: PosQualityBytes::from(quality),
-            challenge,
-            tables: &self.tables,
-        })
+
+        let proof = self
+            .tables
+            .find_proof(&challenge)
+            .next()
+            .map(PosProof::from);
+        proof
     }
 
-    fn is_proof_valid(
-        seed: &PosSeed,
-        challenge_index: u32,
-        proof: &PosProof,
-    ) -> Option<PosQualityBytes> {
+    fn is_proof_valid(seed: &PosSeed, challenge_index: u32, proof: &PosProof) -> bool {
         let mut challenge = [0; 32];
         challenge[..mem::size_of::<u32>()].copy_from_slice(&challenge_index.to_le_bytes());
-        Tables::<K>::verify(**seed, &challenge, proof).map(PosQualityBytes::from)
+        Tables::<K>::verify(**seed, &challenge, proof).is_some()
     }
 }
 
@@ -117,22 +87,14 @@ mod tests {
         let table = ChiaTable::generate(&seed);
         let table_parallel = ChiaTable::generate_parallel(&seed);
 
-        assert!(table.find_quality(1232460437).is_none());
-        assert!(table_parallel.find_quality(1232460437).is_none());
+        assert!(table.find_proof(1232460437).is_none());
+        assert!(table_parallel.find_proof(1232460437).is_none());
 
         {
             let challenge_index = 600426542;
-            let quality = table.find_quality(challenge_index).unwrap();
-            assert_eq!(
-                quality.to_bytes(),
-                table_parallel
-                    .find_quality(challenge_index)
-                    .unwrap()
-                    .to_bytes()
-            );
-            let proof = quality.create_proof();
-            let maybe_quality = ChiaTable::is_proof_valid(&seed, challenge_index, &proof);
-            assert_eq!(maybe_quality, Some(quality.to_bytes()));
+            let proof = table.find_proof(challenge_index).unwrap();
+            assert_eq!(proof, table_parallel.find_proof(challenge_index).unwrap());
+            assert!(ChiaTable::is_proof_valid(&seed, challenge_index, &proof));
         }
     }
 }

crates/subspace-proof-of-space/src/chiapos/tables.rs

@@ -336,6 +336,8 @@ where
                 let mut hasher = Sha256::new();
                 hasher.update(challenge);
 
+                // NOTE: this works correctly, but may overflow if `quality_index` is changed to
+                // not be zero-initialized anymore
                 let left_right_xs_bit_offset = quality_index * usize::from(K * 2);
                 // Collect `left_x` and `right_x` bits, potentially with extra bits at the beginning
                 // and the end

crates/subspace-proof-of-space/src/lib.rs

@@ -18,16 +18,7 @@ pub mod chiapos;
 pub mod shim;
 
 use core::fmt;
-use subspace_core_primitives::{PosProof, PosQualityBytes, PosSeed};
-
-/// Abstraction that represents quality of the solution in the table
-pub trait Quality {
-    /// Get underlying bytes representation of the quality
-    fn to_bytes(&self) -> PosQualityBytes;
-
-    /// Create proof for this solution
-    fn create_proof(&self) -> PosProof;
-}
+use subspace_core_primitives::{PosProof, PosSeed};
 
 /// Proof of space table type
 #[derive(Debug, Clone, Copy)]
@@ -62,11 +53,6 @@ pub trait Table: Sized + Send + Sync + 'static {
     /// Instance that can be used to generate tables with better performance
     type Generator: TableGenerator<Self>;
 
-    /// Abstraction that represents quality of the solution in the table
-    type Quality<'a>: Quality
-    where
-        Self: 'a;
-
     /// Generate new table with 32 bytes seed.
     ///
     /// There is also [`Self::generate_parallel()`] that can achieve lower latency.
@@ -81,15 +67,11 @@ pub trait Table: Sized + Send + Sync + 'static {
         Self::generate(seed)
     }
 
-    /// Try to find quality of the proof at `challenge_index` if proof exists
-    fn find_quality(&self, challenge_index: u32) -> Option<Self::Quality<'_>>;
+    /// Try to find proof at `challenge_index` if it exists
+    fn find_proof(&self, challenge_index: u32) -> Option<PosProof>;
 
     /// Check whether proof created earlier is valid and return quality bytes if yes
-    fn is_proof_valid(
-        seed: &PosSeed,
-        challenge_index: u32,
-        proof: &PosProof,
-    ) -> Option<PosQualityBytes>;
+    fn is_proof_valid(seed: &PosSeed, challenge_index: u32, proof: &PosProof) -> bool;
 
     /// Returns a stateful table generator with better performance
     fn generator() -> Self::Generator {