feat(circuits): add poll joined circuit

- [x] Add poll joined circuit
- [x] Add poll joined vk

packages/circuits/circom/anon/pollJoining.circom → packages/circuits/circom/anon/poll.circom

@@ -49,3 +49,43 @@ template PollJoining(stateTreeDepth) {
 
     calculatedRoot === stateRoot;
 }
+
+template PollJoined(stateTreeDepth) {
+    // Constants defining the tree structure
+    var STATE_TREE_ARITY = 2;
+
+    // User's private key
+    signal input privKey;
+    // Poll's private key
+    signal input pollPrivKey;
+    // Poll's public key
+    signal input pollPubKey[2];
+    // User's voice credits balance
+    signal input voiceCreditsBalance;
+    // Poll's joined timestamp
+    signal input joinTimestamp;
+    // Path elements
+    signal input pathElements[stateTreeDepth][STATE_TREE_ARITY - 1];
+    // Path indices
+    signal input pathIndices[stateTreeDepth];
+    // Poll State tree root which proves the user is joined
+    signal input stateRoot;
+    // The poll id
+    signal input pollId;
+
+    // Poll private to public key to verify the correct one is used to join the poll (public input)
+    var derivedPollPubKey[2] = PrivToPubKey()(pollPrivKey);
+    derivedPollPubKey[0] === pollPubKey[0];
+    derivedPollPubKey[1] === pollPubKey[1];
+
+    var stateLeaf = PoseidonHasher(4)([derivedPollPubKey[0], derivedPollPubKey[1], voiceCreditsBalance, joinTimestamp]);
+
+    // Inclusion proof  
+    var stateLeafQip = MerkleTreeInclusionProof(stateTreeDepth)(
+        stateLeaf,
+        pathIndices,
+        pathElements
+    );
+
+    stateLeafQip === stateRoot;
+}

packages/circuits/circom/circuits.json

@@ -1,10 +1,16 @@
 {
   "PollJoining_10_test": {
-    "file": "./anon/pollJoining",
+    "file": "./anon/poll",
     "template": "PollJoining",
     "params": [10],
     "pubs": ["nullifier", "stateRoot", "pollPubKey", "pollId"]
   },
+  "PollJoined_10_test": {
+    "file": "./anon/poll",
+    "template": "PollJoined",
+    "params": [10],
+    "pubs": ["stateRoot", "pollPubKey", "pollId"]
+  },
   "ProcessMessages_10-20-2_test": {
     "file": "./core/qv/processMessages",
     "template": "ProcessMessages",

packages/circuits/package.json

@@ -35,7 +35,8 @@
     "test:tallyVotes": "pnpm run mocha-test ts/__tests__/TallyVotes.test.ts",
     "test:ceremonyParams": "pnpm run mocha-test ts/__tests__/CeremonyParams.test.ts",
     "test:incrementalQuinaryTree": "pnpm run mocha-test ts/__tests__/IncrementalQuinaryTree.test.ts",
-    "test:pollJoining": "pnpm run mocha-test ts/__tests__/PollJoining.test.ts"
+    "test:pollJoining": "pnpm run mocha-test ts/__tests__/PollJoining.test.ts",
+    "test:pollJoined": "pnpm run mocha-test ts/__tests__/PollJoined.test.ts"
   },
   "dependencies": {
     "@zk-kit/circuits": "^0.4.0",

packages/circuits/ts/__tests__/PollJoined.test.ts

@@ -0,0 +1,134 @@
+import { type WitnessTester } from "circomkit";
+import { MaciState, Poll } from "maci-core";
+import { poseidon } from "maci-crypto";
+import { Keypair, Message, PCommand } from "maci-domainobjs";
+
+import type { IPollJoinedInputs } from "../types";
+
+import { STATE_TREE_DEPTH, duration, messageBatchSize, treeDepths, voiceCreditBalance } from "./utils/constants";
+import { circomkitInstance } from "./utils/utils";
+
+describe("Poll Joined circuit", function test() {
+  this.timeout(900000);
+  const NUM_USERS = 50;
+
+  const coordinatorKeypair = new Keypair();
+
+  type PollJoinedCircuitInputs = [
+    "privKey",
+    "pollPrivKey",
+    "pollPubKey",
+    "voiceCreditsBalance",
+    "joinTimestamp",
+    "stateLeaf",
+    "pathElements",
+    "pathIndices",
+    "stateRoot",
+    "pollId",
+  ];
+
+  let circuit: WitnessTester<PollJoinedCircuitInputs>;
+
+  before(async () => {
+    circuit = await circomkitInstance.WitnessTester("pollJoined", {
+      file: "./anon/poll",
+      template: "PollJoined",
+      params: [STATE_TREE_DEPTH],
+    });
+  });
+
+  describe(`${NUM_USERS} users, 1 join`, () => {
+    const maciState = new MaciState(STATE_TREE_DEPTH);
+    let pollId: bigint;
+    let poll: Poll;
+    let users: Keypair[];
+    const { privKey: pollPrivKey, pubKey: pollPubKey } = new Keypair();
+    const messages: Message[] = [];
+    const commands: PCommand[] = [];
+
+    const timestamp = BigInt(Math.floor(Date.now() / 1000));
+
+    before(() => {
+      // Sign up
+      users = new Array(NUM_USERS).fill(0).map(() => new Keypair());
+
+      users.forEach((userKeypair) => {
+        maciState.signUp(userKeypair.pubKey);
+      });
+
+      pollId = maciState.deployPoll(timestamp + BigInt(duration), treeDepths, messageBatchSize, coordinatorKeypair);
+
+      poll = maciState.polls.get(pollId)!;
+      poll.updatePoll(BigInt(maciState.pubKeys.length));
+
+      // Join the poll
+      const { privKey } = users[0];
+
+      const nullifier = poseidon([BigInt(privKey.rawPrivKey.toString())]);
+
+      const stateIndex = BigInt(poll.joinPoll(nullifier, pollPubKey, voiceCreditBalance, timestamp));
+
+      // First command (valid)
+      const command = new PCommand(
+        stateIndex,
+        pollPubKey,
+        BigInt(0), // voteOptionIndex,
+        BigInt(9), // vote weight
+        BigInt(1), // nonce
+        BigInt(pollId),
+      );
+
+      const signature = command.sign(pollPrivKey);
+
+      const ecdhKeypair = new Keypair();
+      const sharedKey = Keypair.genEcdhSharedKey(ecdhKeypair.privKey, coordinatorKeypair.pubKey);
+      const message = command.encrypt(signature, sharedKey);
+      messages.push(message);
+      commands.push(command);
+
+      poll.publishMessage(message, ecdhKeypair.pubKey);
+
+      // Process messages
+      poll.processMessages(pollId);
+    });
+
+    it("should produce a proof", async () => {
+      const privateKey = users[0].privKey;
+      const nullifier = poseidon([BigInt(privateKey.asCircuitInputs()), poll.pollId]);
+
+      const stateLeafIndex = poll.joinPoll(nullifier, pollPubKey, voiceCreditBalance, timestamp);
+
+      const inputs = poll.joinedCircuitInputs({
+        maciPrivKey: privateKey,
+        stateLeafIndex: BigInt(stateLeafIndex),
+        pollPrivKey,
+        pollPubKey,
+        voiceCreditsBalance: voiceCreditBalance,
+        joinTimestamp: timestamp,
+      }) as unknown as IPollJoinedInputs;
+
+      const witness = await circuit.calculateWitness(inputs);
+      await circuit.expectConstraintPass(witness);
+    });
+
+    it("should fail for fake witness", async () => {
+      const privateKey = users[1].privKey;
+      const nullifier = poseidon([BigInt(privateKey.asCircuitInputs()), poll.pollId]);
+
+      const stateLeafIndex = poll.joinPoll(nullifier, pollPubKey, voiceCreditBalance, timestamp);
+
+      const inputs = poll.joinedCircuitInputs({
+        maciPrivKey: privateKey,
+        stateLeafIndex: BigInt(stateLeafIndex),
+        pollPrivKey,
+        pollPubKey,
+        voiceCreditsBalance: voiceCreditBalance,
+        joinTimestamp: timestamp,
+      }) as unknown as IPollJoinedInputs;
+      const witness = await circuit.calculateWitness(inputs);
+
+      const fakeWitness = Array(witness.length).fill(1n) as bigint[];
+      await circuit.expectConstraintFail(fakeWitness);
+    });
+  });
+});

packages/circuits/ts/__tests__/PollJoining.test.ts

@@ -30,7 +30,7 @@ describe("Poll Joining circuit", function test() {
 
   before(async () => {
     circuit = await circomkitInstance.WitnessTester("pollJoining", {
-      file: "./anon/pollJoining",
+      file: "./anon/poll",
       template: "PollJoining",
       params: [STATE_TREE_DEPTH],
     });

packages/circuits/ts/types.ts

@@ -56,6 +56,23 @@ export interface IPollJoiningInputs {
   pollId: bigint;
 }
 
+/**
+ * Inputs for circuit PollJoined
+ */
+export interface IPollJoinedInputs {
+  privKey: bigint;
+  pollPrivKey: bigint;
+  pollPubKey: bigint[][];
+  voiceCreditsBalance: bigint;
+  joinTimestamp: bigint;
+  stateLeaf: bigint[];
+  pathElements: bigint[][];
+  pathIndices: bigint[];
+  credits: bigint;
+  stateRoot: bigint;
+  pollId: bigint;
+}
+
 /**
  * Inputs for circuit ProcessMessages
  */

packages/cli/tests/ceremony-params/ceremonyParams.test.ts

@@ -44,6 +44,7 @@ import {
   ceremonyProcessMessagesNonQvWasmPath,
   ceremonyTallyVotesNonQvWasmPath,
   ceremonyPollJoiningZkeyPath,
+  ceremonyPollJoinedZkeyPath,
 } from "../constants";
 import { clean, isArm } from "../utils";
 
@@ -68,6 +69,7 @@ describe("Stress tests with ceremony params (6,3,2,20)", function test() {
     voteOptionTreeDepth,
     messageBatchSize,
     pollJoiningZkeyPath: ceremonyPollJoiningZkeyPath,
+    pollJoinedZkeyPath: ceremonyPollJoinedZkeyPath,
     processMessagesZkeyPathQv: ceremonyProcessMessagesZkeyPath,
     tallyVotesZkeyPathQv: ceremonyTallyVotesZkeyPath,
     processMessagesZkeyPathNonQv: ceremonyProcessMessagesNonQvZkeyPath,

packages/cli/tests/constants.ts

@@ -24,6 +24,7 @@ export const coordinatorPubKey = coordinatorKeypair.pubKey.serialize();
 export const coordinatorPrivKey = coordinatorKeypair.privKey.serialize();
 
 export const pollJoiningTestZkeyPath = "./zkeys/PollJoining_10_test/PollJoining_10_test.0.zkey";
+export const pollJoinedTestZkeyPath = "./zkeys/PollJoined_10_test/PollJoined_10_test.0.zkey";
 export const processMessageTestZkeyPath = "./zkeys/ProcessMessages_10-20-2_test/ProcessMessages_10-20-2_test.0.zkey";
 export const tallyVotesTestZkeyPath = "./zkeys/TallyVotes_10-1-2_test/TallyVotes_10-1-2_test.0.zkey";
 export const processMessageTestNonQvZkeyPath =
@@ -47,6 +48,7 @@ export const testTallyVotesWasmPath =
   "./zkeys/TallyVotes_10-1-2_test/TallyVotes_10-1-2_test_js/TallyVotes_10-1-2_test.wasm";
 export const testRapidsnarkPath = `${homedir()}/rapidsnark/build/prover`;
 export const ceremonyPollJoiningZkeyPath = "./zkeys/PollJoining_10_test/PollJoining_10_test.0.zkey";
+export const ceremonyPollJoinedZkeyPath = "./zkeys/PollJoined_10_test/PollJoined_10_test.0.zkey";
 export const ceremonyProcessMessagesZkeyPath = "./zkeys/ProcessMessages_6-9-2-3/processMessages_6-9-2-3.zkey";
 export const ceremonyProcessMessagesNonQvZkeyPath =
   "./zkeys/ProcessMessagesNonQv_6-9-2-3/processMessagesNonQv_6-9-2-3.zkey";
@@ -98,6 +100,7 @@ export const setVerifyingKeysArgs: Omit<SetVerifyingKeysArgs, "signer"> = {
   voteOptionTreeDepth: VOTE_OPTION_TREE_DEPTH,
   messageBatchSize: MESSAGE_BATCH_SIZE,
   pollJoiningZkeyPath: pollJoiningTestZkeyPath,
+  pollJoinedZkeyPath: pollJoinedTestZkeyPath,
   processMessagesZkeyPathQv: processMessageTestZkeyPath,
   tallyVotesZkeyPathQv: tallyVotesTestZkeyPath,
 };
@@ -109,6 +112,7 @@ export const setVerifyingKeysNonQvArgs: Omit<SetVerifyingKeysArgs, "signer"> = {
   voteOptionTreeDepth: VOTE_OPTION_TREE_DEPTH,
   messageBatchSize: MESSAGE_BATCH_SIZE,
   pollJoiningZkeyPath: pollJoiningTestZkeyPath,
+  pollJoinedZkeyPath: pollJoinedTestZkeyPath,
   processMessagesZkeyPathNonQv: processMessageTestNonQvZkeyPath,
   tallyVotesZkeyPathNonQv: tallyVotesTestNonQvZkeyPath,
 };
@@ -119,6 +123,7 @@ export const checkVerifyingKeysArgs: Omit<CheckVerifyingKeysArgs, "signer"> = {
   voteOptionTreeDepth: VOTE_OPTION_TREE_DEPTH,
   messageBatchSize: MESSAGE_BATCH_SIZE,
   pollJoiningZkeyPath: pollJoiningTestZkeyPath,
+  pollJoinedZkeyPath: pollJoinedTestZkeyPath,
   processMessagesZkeyPath: processMessageTestZkeyPath,
   tallyVotesZkeyPath: tallyVotesTestZkeyPath,
 };

packages/cli/ts/commands/checkVerifyingKeys.ts

@@ -32,6 +32,7 @@ export const checkVerifyingKeys = async ({
   processMessagesZkeyPath,
   tallyVotesZkeyPath,
   pollJoiningZkeyPath,
+  pollJoinedZkeyPath,
   vkRegistry,
   signer,
   useQuadraticVoting = true,
@@ -69,30 +70,28 @@ export const checkVerifyingKeys = async ({
   // extract the verification keys from the zkey files
   const processVk = VerifyingKey.fromObj(await extractVk(processMessagesZkeyPath));
   const tallyVk = VerifyingKey.fromObj(await extractVk(tallyVotesZkeyPath));
-  const pollVk = VerifyingKey.fromObj(await extractVk(pollJoiningZkeyPath));
+  const pollJoiningVk = VerifyingKey.fromObj(await extractVk(pollJoiningZkeyPath));
+  const pollJoinedVk = VerifyingKey.fromObj(await extractVk(pollJoinedZkeyPath));
 
   try {
     logYellow(quiet, info("Retrieving verifying keys from the contract..."));
     // retrieve the verifying keys from the contract
 
-    const pollVkOnChain = await vkRegistryContractInstance.getPollVk(stateTreeDepth, voteOptionTreeDepth);
+    const mode = useQuadraticVoting ? EMode.QV : EMode.NON_QV;
 
-    const processVkOnChain = await vkRegistryContractInstance.getProcessVk(
-      stateTreeDepth,
-      voteOptionTreeDepth,
-      messageBatchSize,
-      useQuadraticVoting ? EMode.QV : EMode.NON_QV,
-    );
-
-    const tallyVkOnChain = await vkRegistryContractInstance.getTallyVk(
-      stateTreeDepth,
-      intStateTreeDepth,
-      voteOptionTreeDepth,
-      useQuadraticVoting ? EMode.QV : EMode.NON_QV,
-    );
+    const [pollJoiningVkOnChain, pollJoinedVkOnChain, processVkOnChain, tallyVkOnChain] = await Promise.all([
+      vkRegistryContractInstance.getPollJoiningVk(stateTreeDepth, voteOptionTreeDepth),
+      vkRegistryContractInstance.getPollJoinedVk(stateTreeDepth, voteOptionTreeDepth),
+      vkRegistryContractInstance.getProcessVk(stateTreeDepth, voteOptionTreeDepth, messageBatchSize, mode),
+      vkRegistryContractInstance.getTallyVk(stateTreeDepth, intStateTreeDepth, voteOptionTreeDepth, mode),
+    ]);
 
     // do the actual validation
-    if (!compareVks(pollVk, pollVkOnChain)) {
+    if (!compareVks(pollJoiningVk, pollJoiningVkOnChain)) {
+      logError("Poll verifying keys do not match");
+    }
+
+    if (!compareVks(pollJoinedVk, pollJoinedVkOnChain)) {
       logError("Poll verifying keys do not match");
     }
 

packages/cli/ts/commands/extractVkToFile.ts

@@ -15,20 +15,22 @@ export const extractVkToFile = async ({
   processMessagesZkeyPathQv,
   tallyVotesZkeyPathQv,
   processMessagesZkeyPathNonQv,
-  tallyVotesZkeyPathNonQv,
+  pollJoinedZkeyPath,
   pollJoiningZkeyPath,
+  tallyVotesZkeyPathNonQv,
   outputFilePath,
 }: ExtractVkToFileArgs): Promise<void> => {
-  const [processVkQv, tallyVkQv, processVkNonQv, tallyVkNonQv, pollVk] = await Promise.all([
+  const [processVkQv, tallyVkQv, processVkNonQv, tallyVkNonQv, pollJoiningVk, pollJoinedVk] = await Promise.all([
     extractVk(processMessagesZkeyPathQv),
     extractVk(tallyVotesZkeyPathQv),
     extractVk(processMessagesZkeyPathNonQv),
     extractVk(tallyVotesZkeyPathNonQv),
     extractVk(pollJoiningZkeyPath),
+    extractVk(pollJoinedZkeyPath),
   ]);
 
   await fs.promises.writeFile(
     outputFilePath,
-    JSON.stringify({ processVkQv, tallyVkQv, processVkNonQv, tallyVkNonQv, pollVk }),
+    JSON.stringify({ processVkQv, tallyVkQv, processVkNonQv, tallyVkNonQv, pollJoiningVk, pollJoinedVk }),
   );
 };