feat: integrate semaphore circuit

circuits/.gitignore

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+ptau
+main
+test
+node_modules
+build

circuits/.yarnrc.yml

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+nodeLinker: node-modules

circuits/circomkit.json

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+{
+  "protocol": "groth16",
+  "prime": "bn128",
+  "version": "2.1.5",
+  "circuits": "./circuits.json",
+  "dirPtau": "./ptau",
+  "dirCircuits": "./src",
+  "dirInputs": "./inputs",
+  "dirBuild": "./build",
+  "optimization": 2,
+  "inspect": true,
+  "include": [
+    "./node_modules/circomlib/circuits/sha256",
+    "./node_modules/@zk-kit/binary-merkle-root.circom/src",
+    "./node_modules/circomlib/circuits"
+  ],
+  "groth16numContributions": 1,
+  "groth16askForEntropy": false,
+  "logLevel": "INFO",
+  "verbose": true
+}

circuits/circuits.json

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+{
+  "semaphore": {
+    "file": "semaphore",
+    "template": "Semaphore",
+    "pubs": ["message", "scope"],
+    "params": [10]
+  }
+}

circuits/package.json

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+{
+  "scripts": {
+    "compile": "circomkit compile semaphore"
+  },
+  "dependencies": {
+    "@zk-kit/binary-merkle-root.circom": "^1.0.0",
+    "circomlib": "^2.0.5"
+  },
+  "packageManager": "yarn@1.22.22+sha512.a6b2f7906b721bba3d67d4aff083df04dad64c399707841b7acf00f6b133b7ac24255f2652fa22ae3534329dc6180534e98d17432037ff6fd140556e2bb3137e",
+  "devDependencies": {
+    "@types/mocha": "^10.0.10",
+    "circomkit": "^0.3.1",
+    "mocha": "^10.8.2"
+  }
+}

circuits/src/semaphore.circom

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+pragma circom 2.1.5;
+
+include "babyjub.circom";
+include "poseidon.circom";
+include "binary-merkle-root.circom";
+include "comparators.circom";
+
+template Semaphore(MAX_DEPTH) {
+    signal input secret;
+    signal input merkleProofLength, merkleProofIndices[MAX_DEPTH], merkleProofSiblings[MAX_DEPTH];
+    signal input message;
+    signal input scope;
+
+    signal output merkleRoot, nullifier;
+
+    // Keep BabyJubjub curve parameters
+    var l = 2736030358979909402780800718157159386076813972158567259200215660948447373041;
+
+    component isLessThan = LessThan(251);
+    isLessThan.in <== [secret, l];
+    isLessThan.out === 1;
+
+    // Use existing BabyJubjub implementation
+    var Ax, Ay;
+    (Ax, Ay) = BabyPbk()(secret);
+
+    var identityCommitment = Poseidon(2)([Ax, Ay]);
+
+    merkleRoot <== BinaryMerkleRoot(MAX_DEPTH)(identityCommitment, merkleProofLength, merkleProofIndices, merkleProofSiblings);
+
+    nullifier <== Poseidon(2)([scope, secret]);
+
+    signal dummySquare <== message * message;
+}

circuits/tsconfig.json

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+{
+    "compilerOptions": {
+        "target": "es2020",
+        "module": "commonjs",
+        "esModuleInterop": true
+    },
+    "include": [
+        "tests/**/*"
+    ]
+}