fix: under constrained bug binary merkle root (#1012)

* Fix/update binary merkle root circuit version (#1000)

* fix(circuits)!: update binary merkle root circuit version

re #999

* chore: update snarkjs version from 0.7.4 to 0.7.5

* refactor: update the proof package and smart contracts  (#1011)

refactor: update the proof package and smart contracts with new zk artifacts

Author: vplasencia

package.json

@@ -80,7 +80,7 @@
         "prettier": "^3.2.5",
         "rimraf": "^5.0.5",
         "semver": "^7.6.2",
-        "snarkjs": "0.7.4",
+        "snarkjs": "0.7.5",
         "ts-jest": "^29.1.2",
         "ts-node": "^10.9.2",
         "tslib": "^2.6.2",

packages/circuits/package.json

@@ -24,14 +24,14 @@
         "access": "public"
     },
     "dependencies": {
-        "@zk-kit/binary-merkle-root.circom": "1.0.0",
+        "@zk-kit/binary-merkle-root.circom": "2.0.0",
         "circomlib": "2.0.5"
     },
     "devDependencies": {
         "@semaphore-protocol/core": "workspace:^",
         "@types/mocha": "^10.0.6",
         "@zk-kit/baby-jubjub": "1.0.3",
-        "circomkit": "0.0.19",
+        "circomkit": "0.3.3",
         "mocha": "^10.2.0",
         "poseidon-lite": "^0.3.0"
     }

packages/circuits/src/semaphore.circom

@@ -27,7 +27,7 @@ template Semaphore(MAX_DEPTH) {
     // See the Semaphore identity package to know more about how the identity is generated:
     // https://github.com/semaphore-protocol/semaphore/tree/main/packages/identity.
     signal input secret;
-    signal input merkleProofLength, merkleProofIndices[MAX_DEPTH], merkleProofSiblings[MAX_DEPTH];
+    signal input merkleProofLength, merkleProofIndex, merkleProofSiblings[MAX_DEPTH];
     signal input message;
     signal input scope;
 
@@ -58,7 +58,7 @@ template Semaphore(MAX_DEPTH) {
     // the circuit through the inputs of the Merkle proof.
     // See https://github.com/privacy-scaling-explorations/zk-kit.circom/blob/main/packages/binary-merkle-root/src/binary-merkle-root.circom
     // to know more about how the 'BinaryMerkleRoot' template works.
-    merkleRoot <== BinaryMerkleRoot(MAX_DEPTH)(identityCommitment, merkleProofLength, merkleProofIndices, merkleProofSiblings);
+    merkleRoot <== BinaryMerkleRoot(MAX_DEPTH)(identityCommitment, merkleProofLength, merkleProofIndex, merkleProofSiblings);
 
     // Nullifier generation.
     // The nullifier is a value that essentially identifies the proof generated in a specific scope

packages/circuits/tests/common.ts

@@ -12,21 +12,18 @@ export const circomkit = new Circomkit({
 })
 
 export function generateMerkleProof(group: Group, _index: number, maxDepth: number) {
-    const { siblings: merkleProofSiblings, index } = group.generateMerkleProof(_index)
+    const { siblings: merkleProofSiblings, index: merkleProofIndex } = group.generateMerkleProof(_index)
 
-    // The index must be converted to a list of indices, 1 for each tree level.
-    // The circuit tree depth is 20, so the number of siblings must be 20, even if
-    // the tree depth is actually 3. The missing siblings can be set to 0, as they
-    // won't be used to calculate the root in the circuit.
-    const merkleProofIndices: number[] = []
+    // For example, if the circuit expects a Merkle tree of depth 20,
+    // the input must always include 20 sibling nodes, even if the actual
+    // tree depth is smaller (e.g., 3). The unused sibling positions can be
+    // filled with 0, as they won't affect the root calculation in the circuit.
 
     for (let i = 0; i < maxDepth; i += 1) {
-        merkleProofIndices.push((index >> i) & 1)
-
         if (merkleProofSiblings[i] === undefined) {
             merkleProofSiblings[i] = BigInt(0)
         }
     }
 
-    return { merkleProofSiblings, merkleProofIndices }
+    return { merkleProofSiblings, merkleProofIndex }
 }

packages/circuits/tests/semaphore.test.ts

@@ -12,7 +12,7 @@ const r = 2188824287183927522224640574525727508854836440041603434369820418657580
 
 describe("semaphore", () => {
     let circuit: WitnessTester<
-        ["secret", "merkleProofLength", "merkleProofIndices", "merkleProofSiblings", "scope", "message"],
+        ["secret", "merkleProofLength", "merkleProofIndex", "merkleProofSiblings", "scope", "message"],
         ["nullifier", "merkleRoot"]
     >
 
@@ -36,12 +36,12 @@ describe("semaphore", () => {
 
         const group = new Group([commitment, 2n, 3n])
 
-        const { merkleProofSiblings, merkleProofIndices } = generateMerkleProof(group, 0, MAX_DEPTH)
+        const { merkleProofSiblings, merkleProofIndex } = generateMerkleProof(group, 0, MAX_DEPTH)
 
         const INPUT = {
             secret,
             merkleProofLength: group.depth,
-            merkleProofIndices,
+            merkleProofIndex,
             merkleProofSiblings,
             scope,
             message
@@ -61,12 +61,12 @@ describe("semaphore", () => {
         const commitment = poseidon2(mulPointEscalar(Base8, secret))
         const group = new Group([commitment, 2n, 3n])
 
-        const { merkleProofSiblings, merkleProofIndices } = generateMerkleProof(group, 0, MAX_DEPTH)
+        const { merkleProofSiblings, merkleProofIndex } = generateMerkleProof(group, 0, MAX_DEPTH)
 
         const INPUT = {
             secret,
             merkleProofLength: group.depth,
-            merkleProofIndices,
+            merkleProofIndex,
             merkleProofSiblings,
             scope,
             message
@@ -81,12 +81,12 @@ describe("semaphore", () => {
         const commitment = poseidon2(mulPointEscalar(Base8, secret))
         const group = new Group([commitment, 2n, 3n])
 
-        const { merkleProofSiblings, merkleProofIndices } = generateMerkleProof(group, 0, MAX_DEPTH)
+        const { merkleProofSiblings, merkleProofIndex } = generateMerkleProof(group, 0, MAX_DEPTH)
 
         const INPUT = {
             secret,
             merkleProofLength: group.depth,
-            merkleProofIndices,
+            merkleProofIndex,
             merkleProofSiblings,
             scope,
             message
@@ -100,12 +100,12 @@ describe("semaphore", () => {
 
         const group = new Group([commitment, 2n, 3n])
 
-        const { merkleProofSiblings, merkleProofIndices } = generateMerkleProof(group, 0, MAX_DEPTH)
+        const { merkleProofSiblings, merkleProofIndex } = generateMerkleProof(group, 0, MAX_DEPTH)
 
         const INPUT = {
             secret,
             merkleProofLength: group.depth,
-            merkleProofIndices,
+            merkleProofIndex,
             merkleProofSiblings,
             scope,
             message

packages/contracts/contracts/base/Constants.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity >=0.8.23 <=0.8.28;
+pragma solidity >=0.8.23 <0.9.0;
 
 /// @dev Minimum supported tree depth.
 uint8 constant MIN_DEPTH = 1;

packages/contracts/contracts/base/SemaphoreGroups.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity >=0.8.23 <=0.8.28;
+pragma solidity >=0.8.23 <0.9.0;
 
 import {ISemaphoreGroups} from "../interfaces/ISemaphoreGroups.sol";
 import {InternalLeanIMT, LeanIMTData} from "@zk-kit/lean-imt.sol/InternalLeanIMT.sol";

packages/contracts/contracts/base/SemaphoreVerifier.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 // Part of this file was generated with [snarkJS](https://github.com/iden3/snarkjs).
 
-pragma solidity >=0.8.23 <=0.8.28;
+pragma solidity >=0.8.23 <0.9.0;
 
 import {MAX_DEPTH} from "./Constants.sol";
 import {SemaphoreVerifierKeyPts} from "./SemaphoreVerifierKeyPts.sol";