imp: add proof caching for aggregation (#110)

* feat: added caching

* imp: limited code to membership and added tests

* imp: improved contract and test

* style: renamed tests

* lint: fixed linter issues

* style: addressed review items

contracts/src/SP1ICS07Tendermint.sol

@@ -42,6 +42,8 @@ contract SP1ICS07Tendermint is
     ClientState private clientState;
     /// @notice The mapping from height to consensus state keccak256 hashes.
     mapping(uint32 height => bytes32 hash) private consensusStateHashes;
+    /// @notice The collection of verified SP1 proofs for caching.
+    mapping(bytes32 sp1ProofHash => bool isVerified) private verifiedProofs;
 
     /// @notice Allowed clock drift in seconds.
     /// @inheritdoc ISP1ICS07Tendermint
@@ -178,7 +180,6 @@ contract SP1ICS07Tendermint is
         bytes calldata kvValue
     )
         private
-        view
         returns (uint256)
     {
         if (proofHeight.revisionNumber != clientState.latestHeight.revisionNumber) {
@@ -222,7 +223,12 @@ contract SP1ICS07Tendermint is
 
         validateMembershipOutput(output.commitmentRoot, proofHeight.revisionHeight, proof.trustedConsensusState);
 
-        verifySP1Proof(proof.sp1Proof);
+        // We avoid the cost of caching for single kv pairs, as reusing the proof is not necessary
+        if (output.kvPairs.length == 1) {
+            verifySP1Proof(proof.sp1Proof);
+        } else {
+            verifySP1ProofCached(proof.sp1Proof);
+        }
 
         return proof.trustedConsensusState.timestamp;
     }
@@ -234,6 +240,7 @@ contract SP1ICS07Tendermint is
     /// @param kvPath The path of the key-value pair.
     /// @param kvValue The value of the key-value pair.
     /// @return The timestamp of the new consensus state.
+    // solhint-disable-next-line code-complexity
     function handleSP1UpdateClientAndMembership(
         Height calldata proofHeight,
         bytes memory proofBytes,
@@ -270,7 +277,12 @@ contract SP1ICS07Tendermint is
 
             validateUpdateClientPublicValues(output.updateClientOutput);
 
-            verifySP1Proof(proof.sp1Proof);
+            // We avoid the cost of caching for single kv pairs, as reusing the proof is not necessary
+            if (output.kvPairs.length == 1) {
+                verifySP1Proof(proof.sp1Proof);
+            } else {
+                verifySP1ProofCached(proof.sp1Proof);
+            }
         }
 
         // check update result
@@ -438,12 +450,25 @@ contract SP1ICS07Tendermint is
         }
     }
 
-    /// @notice Verifies the SP1 proof.
+    /// @notice Verifies the SP1 proof
     /// @param proof The SP1 proof.
     function verifySP1Proof(SP1Proof memory proof) private view {
         VERIFIER.verifyProof(proof.vKey, proof.publicValues, proof.proof);
     }
 
+    /// @notice Verifies the SP1 proof and stores the hash of the proof.
+    /// @dev If the proof is already cached, it does not verify the proof again.
+    /// @param proof The SP1 proof.
+    function verifySP1ProofCached(SP1Proof memory proof) private {
+        bytes32 proofHash = keccak256(abi.encode(proof));
+        if (verifiedProofs[proofHash]) {
+            return;
+        }
+
+        VERIFIER.verifyProof(proof.vKey, proof.publicValues, proof.proof);
+        verifiedProofs[proofHash] = true;
+    }
+
     /// @notice A dummy function to generate the ABI for the parameters.
     /// @param o1 The MembershipOutput.
     /// @param o2 The UcAndMembershipOutput.

contracts/test/Membership.t.sol

@@ -41,24 +41,51 @@ contract SP1ICS07MembershipTest is MembershipTest {
 
         ics07Tendermint.membership(membershipMsg);
 
-        // to console
-        console.log("VerifyMultiMembership gas used: ", vm.lastCallGas().gasTotalUsed);
+        console.log("VerifyMembership gas used: ", vm.lastCallGas().gasTotalUsed);
     }
 
     // Modify the proof to make it a non-membership proof.
     function test_ValidVerifyNonMembership() public {
-        MsgMembership memory membershipMsg = MsgMembership({
+        MsgMembership memory nonMembershipMsg = MsgMembership({
             proof: abi.encode(fixture.membershipProof),
             proofHeight: fixture.proofHeight,
             path: verifyNonMembershipPath,
             value: bytes("")
         });
 
-        ics07Tendermint.membership(membershipMsg);
-        // to console
+        ics07Tendermint.membership(nonMembershipMsg);
+
         console.log("VerifyNonMembership gas used: ", vm.lastCallGas().gasTotalUsed);
     }
 
+    function test_ValidCachedMembership() public {
+        MsgMembership memory membershipMsg = MsgMembership({
+            proof: abi.encode(fixture.membershipProof),
+            proofHeight: fixture.proofHeight,
+            path: verifyMembershipPath,
+            value: verifyMembershipValue()
+        });
+
+        ics07Tendermint.membership(membershipMsg);
+
+        // resubmit the same proof
+        ics07Tendermint.membership(membershipMsg);
+
+        console.log("Cached VerifyMembership gas used: ", vm.lastCallGas().gasTotalUsed);
+
+        // resubmit the same proof as non-membership
+        MsgMembership memory nonMembershipMsg = MsgMembership({
+            proof: abi.encode(fixture.membershipProof),
+            proofHeight: fixture.proofHeight,
+            path: verifyNonMembershipPath,
+            value: bytes("")
+        });
+
+        ics07Tendermint.membership(nonMembershipMsg);
+
+        console.log("Cached VerifyNonMembership gas used: ", vm.lastCallGas().gasTotalUsed);
+    }
+
     // Confirm that submitting an invalid proof with the real verifier fails.
     function test_Invalid_VerifyMembership() public {
         SP1MembershipProof memory proofMsg = proof;

contracts/test/UcAndMembership.t.sol

@@ -44,7 +44,6 @@ contract SP1ICS07UpdateClientAndMembershipTest is MembershipTest {
         // run verify
         ics07Tendermint.membership(membershipMsg);
 
-        // to console
         console.log("UpdateClientAndVerifyMembership gas used: ", vm.lastCallGas().gasTotalUsed);
 
         ClientState memory clientState = ics07Tendermint.getClientState();
@@ -62,17 +61,16 @@ contract SP1ICS07UpdateClientAndMembershipTest is MembershipTest {
         // set a correct timestamp
         vm.warp(output.updateClientOutput.env.now + 300);
 
-        MsgMembership memory membershipMsg = MsgMembership({
+        MsgMembership memory nonMembershipMsg = MsgMembership({
             proof: abi.encode(fixture.membershipProof),
             proofHeight: fixture.proofHeight,
             path: verifyNonMembershipPath,
             value: bytes("")
         });
 
         // run verify
-        ics07Tendermint.membership(membershipMsg);
+        ics07Tendermint.membership(nonMembershipMsg);
 
-        // to console
         console.log("UpdateClientAndVerifyNonMembership gas used: ", vm.lastCallGas().gasTotalUsed);
 
         ClientState memory clientState = ics07Tendermint.getClientState();
@@ -84,6 +82,48 @@ contract SP1ICS07UpdateClientAndMembershipTest is MembershipTest {
         assert(consensusHash == keccak256(abi.encode(output.updateClientOutput.newConsensusState)));
     }
 
+    // Confirm that submitting a real proof passes the verifier.
+    function test_Valid_CachedUpdateClientAndMembership() public {
+        UcAndMembershipOutput memory output = abi.decode(proof.sp1Proof.publicValues, (UcAndMembershipOutput));
+        // set a correct timestamp
+        vm.warp(output.updateClientOutput.env.now + 300);
+
+        MsgMembership memory membershipMsg = MsgMembership({
+            proof: abi.encode(fixture.membershipProof),
+            proofHeight: fixture.proofHeight,
+            path: verifyMembershipPath,
+            value: verifyMembershipValue()
+        });
+
+        // run verify
+        ics07Tendermint.membership(membershipMsg);
+
+        ClientState memory clientState = ics07Tendermint.getClientState();
+        assert(clientState.latestHeight.revisionHeight == output.updateClientOutput.newHeight.revisionHeight);
+        assert(clientState.isFrozen == false);
+
+        bytes32 consensusHash =
+            ics07Tendermint.getConsensusStateHash(output.updateClientOutput.newHeight.revisionHeight);
+        assert(consensusHash == keccak256(abi.encode(output.updateClientOutput.newConsensusState)));
+
+        // resubmit the same proof
+        ics07Tendermint.membership(membershipMsg);
+
+        console.log("Cached UpdateClientAndVerifyMembership gas used: ", vm.lastCallGas().gasTotalUsed);
+
+        MsgMembership memory nonMembershipMsg = MsgMembership({
+            proof: abi.encode(fixture.membershipProof),
+            proofHeight: fixture.proofHeight,
+            path: verifyNonMembershipPath,
+            value: bytes("")
+        });
+
+        // run verify
+        ics07Tendermint.membership(nonMembershipMsg);
+
+        console.log("Cached UpdateClientAndNonVerifyMembership gas used: ", vm.lastCallGas().gasTotalUsed);
+    }
+
     // Confirm that submitting a real proof passes the verifier.
     function test_Invalid_UpdateClientAndMembership() public {
         UcAndMembershipOutput memory output = abi.decode(proof.sp1Proof.publicValues, (UcAndMembershipOutput));