zcash_primitives: Add Sapling verification key newtypes

zcash_primitives/CHANGELOG.md

@@ -13,6 +13,8 @@ and this library adheres to Rust's notion of
   - `SaplingVerificationContext` (moved from `zcash_proofs::sapling`).
   - `circuit` module (moved from `zcash_proofs::circuit::sapling`).
   - `circuit::{SpendParameters, OutputParameters}`
+  - `circuit::{SpendVerifyingKey, PreparedSpendVerifyingKey}`
+  - `circuit::{OutputVerifyingKey, PreparedOutputVerifyingKey}`
   - `constants` module.
   - `prover::{SpendProver, OutputProver}`
   - `value`:
@@ -61,6 +63,11 @@ and this library adheres to Rust's notion of
 
 ### Changed
 - `zcash_primitives::sapling`:
+  - `BatchValidator::validate` now takes the `SpendVerifyingKey` and
+    `OutputVerifyingKey` newtypes.
+  - `SaplingVerificationContext::{check_spend, check_output}` now take
+    the `PreparedSpendVerifyingKey` and `PreparedOutputVerifyingKey`
+    newtypes.
   - `address::PaymentAddress::create_note` now takes its `value` argument as a
     `NoteValue` instead of as a bare `u64`.
   - `circuit::ValueCommitmentOpening::value` is now represented as a `NoteValue`

zcash_primitives/src/sapling/circuit.rs

@@ -566,11 +566,31 @@ impl SpendParameters {
     }
 
     /// Returns the verifying key for the Sapling Spend circuit.
-    pub fn verifying_key(&self) -> &groth16::VerifyingKey<Bls12> {
+    pub fn verifying_key(&self) -> SpendVerifyingKey {
-        &self.0.vk
+        SpendVerifyingKey(self.0.vk.clone())
+    }
+
+    /// Returns the verifying key for the Sapling Spend circuit, with precomputations
+    /// optimized for verifying individual proofs.
+    pub fn prepared_verifying_key(&self) -> PreparedSpendVerifyingKey {
+        PreparedSpendVerifyingKey(groth16::prepare_verifying_key(&self.0.vk))
     }
 }
 
+/// The verifying key for the Sapling Spend circuit.
+pub struct SpendVerifyingKey(pub(crate) groth16::VerifyingKey<Bls12>);
+
+impl SpendVerifyingKey {
+    /// Performs precomputations optimized for verifying individual proofs.
+    pub fn prepare(&self) -> PreparedSpendVerifyingKey {
+        PreparedSpendVerifyingKey(groth16::prepare_verifying_key(&self.0))
+    }
+}
+
+/// The verifying key for the Sapling Spend circuit, with precomputations optimized for
+/// verifying individual proofs.
+pub struct PreparedSpendVerifyingKey(pub(crate) groth16::PreparedVerifyingKey<Bls12>);
+
 /// The parameters for the Sapling Output circuit.
 pub struct OutputParameters(pub(crate) groth16::Parameters<Bls12>);
 
@@ -584,11 +604,31 @@ impl OutputParameters {
     }
 
     /// Returns the verifying key for the Sapling Output circuit.
-    pub fn verifying_key(&self) -> &groth16::VerifyingKey<Bls12> {
+    pub fn verifying_key(&self) -> OutputVerifyingKey {
-        &self.0.vk
+        OutputVerifyingKey(self.0.vk.clone())
+    }
+
+    /// Returns the verifying key for the Sapling Output circuit, with precomputations
+    /// optimized for verifying individual proofs.
+    pub fn prepared_verifying_key(&self) -> PreparedOutputVerifyingKey {
+        PreparedOutputVerifyingKey(groth16::prepare_verifying_key(&self.0.vk))
     }
 }
 
+/// The verifying key for the Sapling Output circuit.
+pub struct OutputVerifyingKey(pub(crate) groth16::VerifyingKey<Bls12>);
+
+impl OutputVerifyingKey {
+    /// Performs precomputations optimized for verifying individual proofs.
+    pub fn prepare(&self) -> PreparedOutputVerifyingKey {
+        PreparedOutputVerifyingKey(groth16::prepare_verifying_key(&self.0))
+    }
+}
+
+/// The verifying key for the Sapling Output circuit, with precomputations optimized for
+/// verifying individual proofs.
+pub struct PreparedOutputVerifyingKey(pub(crate) groth16::PreparedVerifyingKey<Bls12>);
+
 #[test]
 fn test_input_circuit_with_bls12_381() {
     use crate::sapling::{pedersen_hash, Diversifier, Note, ProofGenerationKey, Rseed};

zcash_primitives/src/sapling/verifier/batch.rs

@@ -4,7 +4,10 @@ use group::GroupEncoding;
 use rand_core::{CryptoRng, RngCore};
 
 use super::SaplingVerificationContextInner;
-use crate::transaction::components::sapling::{Authorized, Bundle};
+use crate::{
+    sapling::circuit::{OutputVerifyingKey, SpendVerifyingKey},
+    transaction::components::sapling::{Authorized, Bundle},
+};
 
 /// Batch validation context for Sapling.
 ///
@@ -145,8 +148,8 @@ impl BatchValidator {
     /// is desired, construct separate [`BatchValidator`]s for sub-batches of the bundles.
     pub fn validate<R: RngCore + CryptoRng>(
         self,
-        spend_vk: &groth16::VerifyingKey<Bls12>,
+        spend_vk: &SpendVerifyingKey,
-        output_vk: &groth16::VerifyingKey<Bls12>,
+        output_vk: &OutputVerifyingKey,
         mut rng: R,
     ) -> bool {
         if !self.bundles_added {
@@ -166,12 +169,12 @@ impl BatchValidator {
         let mut verify_proofs =
             |batch: groth16::batch::Verifier<Bls12>, vk| batch.verify(&mut rng, vk);
 
-        if verify_proofs(self.spend_proofs, spend_vk).is_err() {
+        if verify_proofs(self.spend_proofs, &spend_vk.0).is_err() {
             tracing::debug!("Spend proof batch validation failed");
             return false;
         }
 
-        if verify_proofs(self.output_proofs, output_vk).is_err() {
+        if verify_proofs(self.output_proofs, &output_vk.0).is_err() {
             tracing::debug!("Output proof batch validation failed");
             return false;
         }

zcash_primitives/src/sapling/verifier/single.rs

@@ -1,9 +1,10 @@
-use bellman::groth16::{verify_proof, PreparedVerifyingKey, Proof};
+use bellman::groth16::{verify_proof, Proof};
 use bls12_381::Bls12;
 
 use super::SaplingVerificationContextInner;
 use crate::{
     sapling::{
+        circuit::{PreparedOutputVerifyingKey, PreparedSpendVerifyingKey},
         constants::{SPENDING_KEY_GENERATOR, VALUE_COMMITMENT_RANDOMNESS_GENERATOR},
         note::ExtractedNoteCommitment,
         redjubjub::{PublicKey, Signature},
@@ -39,7 +40,7 @@ impl SaplingVerificationContext {
         sighash_value: &[u8; 32],
         spend_auth_sig: Signature,
         zkproof: Proof<Bls12>,
-        verifying_key: &PreparedVerifyingKey<Bls12>,
+        verifying_key: &PreparedSpendVerifyingKey,
     ) -> bool {
         let zip216_enabled = self.zip216_enabled;
         self.inner.check_spend(
@@ -55,7 +56,7 @@ impl SaplingVerificationContext {
                 rk.verify_with_zip216(&msg, spend_auth_sig, SPENDING_KEY_GENERATOR, zip216_enabled)
             },
             |_, proof, public_inputs| {
-                verify_proof(verifying_key, &proof, &public_inputs[..]).is_ok()
+                verify_proof(&verifying_key.0, &proof, &public_inputs[..]).is_ok()
             },
         )
     }
@@ -68,11 +69,11 @@ impl SaplingVerificationContext {
         cmu: ExtractedNoteCommitment,
         epk: jubjub::ExtendedPoint,
         zkproof: Proof<Bls12>,
-        verifying_key: &PreparedVerifyingKey<Bls12>,
+        verifying_key: &PreparedOutputVerifyingKey,
     ) -> bool {
         self.inner
             .check_output(cv, cmu, epk, zkproof, |proof, public_inputs| {
-                verify_proof(verifying_key, &proof, &public_inputs[..]).is_ok()
+                verify_proof(&verifying_key.0, &proof, &public_inputs[..]).is_ok()
             })
     }
 

zcash_proofs/CHANGELOG.md

@@ -11,9 +11,8 @@ and this library adheres to Rust's notion of
   `zcash_proofs::prover::LocalTxProver`
 
 ### Changed
-- The `zcash_proofs::ZcashParameters::{spend_params, output_params}` fields
+- The `zcash_proofs::ZcashParameters` Sapling fields now use the parameter and
-  now have types `zcash_primitives::sapling::circuit::SpendParameters` and
+  viewing key newtypes defined in `zcash_primitives::sapling::circuit`.
-  `zcash_primitives::sapling::circuit::OutputParameters` respectively.
 
 ### Removed
 - `zcash_proofs::circuit::sapling` (moved to `zcash_primitives::sapling::circuit`).

zcash_proofs/src/lib.rs

@@ -11,7 +11,9 @@
 
 use bellman::groth16::{prepare_verifying_key, PreparedVerifyingKey, VerifyingKey};
 use bls12_381::Bls12;
-use zcash_primitives::sapling::circuit::{OutputParameters, SpendParameters};
+use zcash_primitives::sapling::circuit::{
+    OutputParameters, PreparedOutputVerifyingKey, PreparedSpendVerifyingKey, SpendParameters,
+};
 
 use std::fs::File;
 use std::io::{self, BufReader};
@@ -287,9 +289,9 @@ fn stream_params_downloads_to_disk(
 /// Zcash Sprout and Sapling groth16 circuit parameters.
 pub struct ZcashParameters {
     pub spend_params: SpendParameters,
-    pub spend_vk: PreparedVerifyingKey<Bls12>,
+    pub spend_vk: PreparedSpendVerifyingKey,
     pub output_params: OutputParameters,
-    pub output_vk: PreparedVerifyingKey<Bls12>,
+    pub output_vk: PreparedOutputVerifyingKey,
     pub sprout_vk: Option<PreparedVerifyingKey<Bls12>>,
 }
 
@@ -427,8 +429,8 @@ pub fn parse_parameters<R: io::Read>(
     }
 
     // Prepare verifying keys
-    let spend_vk = prepare_verifying_key(spend_params.verifying_key());
+    let spend_vk = spend_params.prepared_verifying_key();
-    let output_vk = prepare_verifying_key(output_params.verifying_key());
+    let output_vk = output_params.prepared_verifying_key();
     let sprout_vk = sprout_vk.map(|vk| prepare_verifying_key(&vk));
 
     ZcashParameters {

zcash_proofs/src/prover.rs

@@ -1,6 +1,6 @@
 //! Abstractions over the proving system and parameters for ease of use.
 
-use bellman::groth16::{PreparedVerifyingKey, Proof};
+use bellman::groth16::Proof;
 use bls12_381::Bls12;
 use std::path::Path;
 use zcash_primitives::{
@@ -22,10 +22,6 @@ use crate::{default_params_folder, SAPLING_OUTPUT_NAME, SAPLING_SPEND_NAME};
 /// locally-accessible paths.
 pub struct LocalTxProver {
     spend_params: SpendParameters,
-    // TODO: Either re-introduce verification-after-proving (once the verifier is
-    // refactored), or remove this.
-    #[allow(unused)]
-    spend_vk: PreparedVerifyingKey<Bls12>,
     output_params: OutputParameters,
 }
 
@@ -52,7 +48,6 @@ impl LocalTxProver {
         let p = load_parameters(spend_path, output_path, None);
         LocalTxProver {
             spend_params: p.spend_params,
-            spend_vk: p.spend_vk,
             output_params: p.output_params,
         }
     }
@@ -77,7 +72,6 @@ impl LocalTxProver {
 
         LocalTxProver {
             spend_params: p.spend_params,
-            spend_vk: p.spend_vk,
             output_params: p.output_params,
         }
     }
@@ -134,7 +128,6 @@ impl LocalTxProver {
 
         LocalTxProver {
             spend_params: p.spend_params,
-            spend_vk: p.spend_vk,
             output_params: p.output_params,
         }
     }