New package for general-purpose Circom circuits

package.json

@@ -32,7 +32,8 @@
         "circom"
     ],
     "workspaces": [
-        "packages/*"
+        "packages/*",
+        "packages/circuits/templates"
     ],
     "packageManager": "[email protected]",
     "devDependencies": {

packages/circuits/LICENSE

@@ -0,0 +1 @@
+templates/LICENSE

packages/circuits/README.md

@@ -0,0 +1 @@
+templates/README.md

packages/circuits/components/binary-merkle-root.circom

@@ -0,0 +1,5 @@
+pragma circom 2.1.5;
+
+include "../templates/binary-merkle-root.circom";
+
+component main {public [depth]} = BinaryMerkleRoot(16);

packages/circuits/components/poseidon-proof.circom

@@ -0,0 +1,5 @@
+pragma circom 2.1.5;
+
+include "../templates/poseidon-proof.circom";
+
+component main {public [scope]} = PoseidonProof();

packages/circuits/package.json

@@ -0,0 +1,9 @@
+{
+    "name": "circuits",
+    "private": true,
+    "description": "A comprehensive library of general-purpose Circom circuits.",
+    "license": "MIT",
+    "scripts": {
+        "compile": "circom --r1cs -l ../../node_modules/circomlib/circuits"
+    }
+}

packages/circuits/templates/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 Ethereum Foundation
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/circuits/templates/README.md

@@ -0,0 +1,50 @@
+<p align="center">
+    <h1 align="center">
+        ZK-kit circuits
+    </h1>
+    <p align="center">A comprehensive library of general-purpose Circom circuits.</p>
+</p>
+
+<p align="center">
+    <a href="https://github.com/privacy-scaling-explorations/zk-kit">
+        <img src="https://img.shields.io/badge/project-zk--kit-blue.svg?style=flat-square">
+    </a>
+    <a href="https://github.com/privacy-scaling-explorations/zk-kit/tree/main/packages/circuits.sol/LICENSE">
+        <img alt="Github license" src="https://img.shields.io/github/license/privacy-scaling-explorations/zk-kit.svg?style=flat-square">
+    </a>
+    <a href="https://www.npmjs.com/package/@zk-kit/circuits">
+        <img alt="NPM version" src="https://img.shields.io/npm/v/@zk-kit/circuits?style=flat-square" />
+    </a>
+    <a href="https://npmjs.org/package/@zk-kit/circuits">
+        <img alt="Downloads" src="https://img.shields.io/npm/dm/@zk-kit/circuits.svg?style=flat-square" />
+    </a>
+    <a href="https://bundlephobia.com/package/@zk-kit/circuits">
+        <img alt="npm bundle size (scoped)" src="https://img.shields.io/bundlephobia/minzip/@zk-kit/circuits" />
+    </a>
+</p>
+
+<div align="center">
+    <h4>
+        <a href="https://appliedzkp.org/discord">
+            🗣️ Chat &amp; Support
+        </a>
+    </h4>
+</div>
+
+---
+
+## 🛠 Install
+
+### npm or yarn
+
+Install the `@zk-kit/circuits` package with npm:
+
+```bash
+npm i @zk-kit/circuits --save
+```
+
+or yarn:
+
+```bash
+yarn add @zk-kit/circuits
+```

packages/circuits/templates/binary-merkle-root.circom

@@ -0,0 +1,32 @@
+pragma circom 2.1.5;
+
+include "poseidon.circom";
+include "mux1.circom";
+include "comparators.circom";
+
+template BinaryMerkleRoot(MAX_DEPTH) {
+    signal input leaf, depth, indices[MAX_DEPTH], siblings[MAX_DEPTH];
+
+    signal output out;
+
+    signal nodes[MAX_DEPTH + 1];
+    nodes[0] <== leaf;
+
+    signal roots[MAX_DEPTH];
+    var root = 0;
+
+    for (var i = 0; i < MAX_DEPTH; i++) {
+        var a = IsEqual()([depth, i]);
+
+        roots[i] <== a * nodes[i];
+
+        root += roots[i];
+
+        var c[2][2] = [ [nodes[i], siblings[i]], [siblings[i], nodes[i]] ];
+        var childNodes[2] = MultiMux1(2)(c, indices[i]);
+
+        nodes[i + 1] <== Poseidon(2)(childNodes);
+    }
+
+    out <== root;
+}

packages/circuits/templates/package.json

@@ -0,0 +1,24 @@
+{
+    "name": "@zk-kit/circuits",
+    "version": "0.1.0",
+    "description": "A comprehensive library of general-purpose Circom circuits.",
+    "license": "MIT",
+    "files": [
+        "**/*.circom",
+        "LICENSE",
+        "README.md"
+    ],
+    "keywords": [
+        "zk-kit",
+        "circom",
+        "circuits"
+    ],
+    "repository": "[email protected]:privacy-scaling-explorations/zk-kit.git",
+    "homepage": "https://github.com/privacy-scaling-explorations/zk-kit/tree/main/packages/circuits.sol",
+    "publishConfig": {
+        "access": "public"
+    },
+    "dependencies": {
+        "circomlib": "^2.0.5"
+    }
+}

packages/circuits/templates/poseidon-proof.circom

@@ -0,0 +1,24 @@
+pragma circom 2.1.5;
+
+include "poseidon.circom";
+
+// This circuit can be used to prove the possession of a pre-image of a
+// hash without revealing the pre-image itself. It utilizes the Poseidon
+// hash function, a highly efficient and secure hash function suited
+// for zero-knowledge proof contexts.
+// A scope value can be used to define a nullifier to prevent the same
+// proof from being re-used twice.
+template PoseidonProof() {
+    // The circuit takes two inputs: the pre-image (in) and an additional scope parameter (scope).
+    signal input in;
+    signal input scope;
+
+    // It applies the Poseidon hash function to the pre-image to produce a hash output (out).
+    signal output out;
+    out <== Poseidon(1)([in]);
+
+    // A nullifier is also computed using both the pre-image and the scope, providing a value
+    // to prevent the same proof from being reused twice.
+    signal output nullifier;
+    nullifier <== Poseidon(2)([scope, in]);
+}

yarn.lock

@@ -4382,6 +4382,14 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@zk-kit/circuits@workspace:packages/circuits/templates":
+  version: 0.0.0-use.local
+  resolution: "@zk-kit/circuits@workspace:packages/circuits/templates"
+  dependencies:
+    circomlib: ^2.0.5
+  languageName: unknown
+  linkType: soft
+
 "@zk-kit/groth16@workspace:packages/groth16":
   version: 0.0.0-use.local
   resolution: "@zk-kit/groth16@workspace:packages/groth16"
@@ -6519,6 +6527,12 @@ __metadata:
   languageName: node
   linkType: hard
 
+"circuits@workspace:packages/circuits":
+  version: 0.0.0-use.local
+  resolution: "circuits@workspace:packages/circuits"
+  languageName: unknown
+  linkType: soft
+
 "cjs-module-lexer@npm:^0.6.0":
   version: 0.6.0
   resolution: "cjs-module-lexer@npm:0.6.0"