From ea712327ad8ee17b2e7e6a0bc23dadd07fea5e34 Mon Sep 17 00:00:00 2001
From: Manish Kumar <kumarmanish19963@gmail.com>
Date: Mon, 21 Oct 2024 13:07:44 +0530
Subject: [PATCH] optimize proofChallengeCalculate

---
 README.md          |  4 +--
 src/bbs_verify.sol | 73 +++++++++++++++++++++++++++++++++++-----------
 2 files changed, 58 insertions(+), 19 deletions(-)

diff --git a/README.md b/README.md
index d0bf277..b851338 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # BBS+ Signature Verifier Smart Contract
 Solidity implementation of the BBS+ Signature Verifier smart contract
 
-- To build: `forge build`
-- Run test: `forge test`
+- To build: `forge build --via-ir`
+- Run test: `forge test --via-ir`
diff --git a/src/bbs_verify.sol b/src/bbs_verify.sol
index 73f7316..896ca74 100644
--- a/src/bbs_verify.sol
+++ b/src/bbs_verify.sol
@@ -590,11 +590,9 @@ contract BBS_Verifier {
 
         uint8[] memory undisclosedIndices = complement(uint8(u), uint8(r), disclosedIndices);
         uint256 domain = calculate_domain(pk, uint64(l));
-        Pairing.G1Point memory t1 = Pairing.scalar_mul(proof.bBar, proof.challenge);
-        Pairing.G1Point memory t11 = Pairing.scalar_mul(proof.aBar, proof.eCap);
-        Pairing.G1Point memory t12 = Pairing.scalar_mul(proof.d, proof.r1Cap);
-        t1 = Pairing.plus(t1, t11);
-        t1 = Pairing.plus(t1, t12);
+        Pairing.G1Point memory temp1 = Pairing.plus(Pairing.scalar_mul(proof.aBar, proof.eCap), Pairing.scalar_mul(proof.d, proof.r1Cap));
+
+        Pairing.G1Point memory t1 = Pairing.plus(Pairing.scalar_mul(proof.bBar, proof.challenge), temp1);
 
         Pairing.G1Point memory bv1 = Pairing.scalar_mul(BBS.generators()[0], domain);
         Pairing.G1Point memory bv = Pairing.plus(BBS.BP1(), bv1);
@@ -605,9 +603,7 @@ contract BBS_Verifier {
         }
         uint256 challenge = proof.challenge;
         Pairing.G1Point memory d = proof.d;
-        Pairing.G1Point memory t21 = Pairing.scalar_mul(bv, challenge);
-        Pairing.G1Point memory t22 = Pairing.scalar_mul(d, proof.r3Cap);
-        Pairing.G1Point memory t2 = Pairing.plus(t21, t22);
+        Pairing.G1Point memory t2 = Pairing.plus(Pairing.scalar_mul(bv, challenge), Pairing.scalar_mul(d, proof.r3Cap));
 
         for (uint256 i = 0; i < u; i++) {
             t2 = Pairing.plus(t2, Pairing.scalar_mul(BBS.generators()[undisclosedIndices[i] + 1], proof.commitments[i]));
@@ -644,23 +640,66 @@ contract BBS_Verifier {
     ) public pure returns (uint256) {
         require(disclosedMsg.length == disclosedIndices.length, "invalid length");
 
-        bytes memory serializeBytes = uint64ToBytes(disclosedIndices.length);
+        uint256 totalLength = 8 + disclosedMsg.length * (8 + 32) + initProof.points.length * 64 + 32 + 8;
+        bytes memory serializeBytes = new bytes(totalLength);
+
+        uint256 serializeBytesPtr;
+        assembly {
+            serializeBytesPtr := add(serializeBytes, 0x20)
+        }
+
+        bytes memory lengthBytes = uint64ToBytes(disclosedIndices.length);
+        assembly {
+            let lenPtr := add(lengthBytes, 0x20)
+            mstore(serializeBytesPtr, mload(lenPtr)) // Copy the lengthBytes (8 bytes)
+            serializeBytesPtr := add(serializeBytesPtr, 8)
+        }
 
+        // Serialize disclosedIndices and disclosedMsg
         for (uint256 i = 0; i < disclosedMsg.length; i++) {
-            serializeBytes = abi.encodePacked(serializeBytes, uint64ToBytes(uint64(disclosedIndices[i])));
-            serializeBytes = abi.encodePacked(serializeBytes, reverseBytes(uintToBytes(disclosedMsg[i])));
+            bytes memory indexBytes = uint64ToBytes(uint64(disclosedIndices[i]));
+            bytes memory msgBytes = reverseBytes(uintToBytes(disclosedMsg[i]));
+
+            assembly {
+                let indexPtr := add(indexBytes, 0x20)
+                mstore(serializeBytesPtr, mload(indexPtr))
+                serializeBytesPtr := add(serializeBytesPtr, 8)
+            }
+
+            // Concatenate msgBytes (32 bytes)
+            assembly {
+                let msgPtr := add(msgBytes, 0x20)
+                mstore(serializeBytesPtr, mload(msgPtr))
+                serializeBytesPtr := add(serializeBytesPtr, 32)
+            }
         }
 
+        // Serialize G1 points
         for (uint256 i = 0; i < initProof.points.length; i++) {
-            serializeBytes = abi.encodePacked(serializeBytes, g1ToBytes(initProof.points[i]));
+            bytes memory pointBytes = g1ToBytes(initProof.points[i]);
+
+            assembly {
+                let pointPtr := add(pointBytes, 0x20)
+                mstore(serializeBytesPtr, mload(pointPtr))
+                mstore(add(serializeBytesPtr, 0x20), mload(add(pointPtr, 0x20))) // Copy 64 bytes for G1 point
+                serializeBytesPtr := add(serializeBytesPtr, 64)
+            }
         }
-        serializeBytes = abi.encodePacked(serializeBytes, reverseBytes(uintToBytes(initProof.scalar)));
 
-        bytes1 zeroByte = 0x00;
-        serializeBytes = abi.encodePacked(
-            serializeBytes, zeroByte, zeroByte, zeroByte, zeroByte, zeroByte, zeroByte, zeroByte, zeroByte
-        );
+        // Serialize scalar (32 bytes)
+        bytes memory scalarBytes = reverseBytes(uintToBytes(initProof.scalar));
+        assembly {
+            let scalarPtr := add(scalarBytes, 0x20)
+            mstore(serializeBytesPtr, mload(scalarPtr)) // Copy 32 bytes
+            serializeBytesPtr := add(serializeBytesPtr, 32)
+        }
+
+        assembly {
+            mstore(serializeBytesPtr, 0) // Zero bytes
+            serializeBytesPtr := add(serializeBytesPtr, 8)
+        }
 
+        // Return the calculated hash using BBS.hashToScalar
         return BBS.hashToScalar(serializeBytes, dst);
     }
 }