Trim ring when too many keys

davxy · Jul 10, 2024 · cf8d875 · cf8d875
1 parent efd5a7e
commit cf8d875
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Showing 2 changed files with 18 additions and 16 deletions.
diff --git a/src/ring.rs b/src/ring.rs
@@ -209,26 +209,28 @@ where
         self.piop_params.keyset_part_size
     }
 
-    pub fn prover_key(&self, pks: &[AffinePoint<S>]) -> Result<ProverKey<S>, Error> {
-        if pks.len() > self.max_ring_size() {
-            return Err(Error::InvalidData);
-        }
+    /// Construct a `ProverKey` instance for the given ring.
+    ///
+    /// Note: if `pks.len() > self.max_ring_size()` the extra keys in the tail are ignored.
+    pub fn prover_key(&self, pks: &[AffinePoint<S>]) -> ProverKey<S> {
+        let pks = &pks[..pks.len().min(self.max_ring_size())];
         #[cfg(feature = "parallel")]
-        let pks = pks.par_iter().map(|p| p.into_sw()).collect();
+        let pks: Vec<_> = pks.par_iter().map(|p| p.into_sw()).collect();
         #[cfg(not(feature = "parallel"))]
-        let pks = pks.iter().map(|p| p.into_sw()).collect();
-        Ok(ring_proof::index(self.pcs_params.clone(), &self.piop_params, pks).0)
+        let pks: Vec<_> = pks.iter().map(|p| p.into_sw()).collect();
+        ring_proof::index(&self.pcs_params, &self.piop_params, &pks).0
     }
 
-    pub fn verifier_key(&self, pks: &[AffinePoint<S>]) -> Result<VerifierKey<S>, Error> {
-        if pks.len() > self.max_ring_size() {
-            return Err(Error::InvalidData);
-        }
+    /// Construct a `VerifierKey` instance for the given ring.
+    ///
+    /// Note: if `pks.len() > self.max_ring_size()` the extra keys in the tail are ignored.
+    pub fn verifier_key(&self, pks: &[AffinePoint<S>]) -> VerifierKey<S> {
+        let pks = &pks[..pks.len().min(self.max_ring_size())];
         #[cfg(feature = "parallel")]
-        let pks = pks.par_iter().map(|p| p.into_sw()).collect();
+        let pks: Vec<_> = pks.par_iter().map(|p| p.into_sw()).collect();
         #[cfg(not(feature = "parallel"))]
-        let pks = pks.iter().map(|p| p.into_sw()).collect();
-        Ok(ring_proof::index(self.pcs_params.clone(), &self.piop_params, pks).1)
+        let pks: Vec<_> = pks.iter().map(|p| p.into_sw()).collect();
+        ring_proof::index(&self.pcs_params, &self.piop_params, &pks).1
     }
 
     pub fn prover(&self, prover_key: ProverKey<S>, key_index: usize) -> RingProver<S> {

diff --git a/src/testing.rs b/src/testing.rs
@@ -94,11 +94,11 @@ where
     let mut pks = random_vec::<AffinePoint<S>>(ring_size, Some(rng));
     pks[prover_idx] = public.0;
 
-    let prover_key = ring_ctx.prover_key(&pks).unwrap();
+    let prover_key = ring_ctx.prover_key(&pks);
     let prover = ring_ctx.prover(prover_key, prover_idx);
     let proof = secret.prove(input, output, b"foo", &prover);
 
-    let verifier_key = ring_ctx.verifier_key(&pks).unwrap();
+    let verifier_key = ring_ctx.verifier_key(&pks);
     let verifier = ring_ctx.verifier(verifier_key);
     let result = Public::verify(input, output, b"foo", &proof, &verifier);
     assert!(result.is_ok());