feat: anonymous poll joining milestone 1

.github/workflows/coordinator-build.yml

@@ -10,7 +10,7 @@ env:
   COORDINATOR_PUBLIC_KEY_PATH: "./pub.key"
   COORDINATOR_PRIVATE_KEY_PATH: "./priv.key"
   COORDINATOR_TALLY_ZKEY_NAME: "TallyVotes_10-1-2_test"
-  COORDINATOR_MESSAGE_PROCESS_ZKEY_NAME: "ProcessMessages_10-2-1-2_test"
+  COORDINATOR_MESSAGE_PROCESS_ZKEY_NAME: "ProcessMessages_10-20-2_test"
   COORDINATOR_ZKEY_PATH: "./zkeys/"
   COORDINATOR_RAPIDSNARK_EXE: "~/rapidsnark/build/prover"
 

circuits/circom/circuits.json

@@ -1,14 +1,14 @@
 {
-  "ProcessMessages_10-2-1-2_test": {
+  "ProcessMessages_10-20-2_test": {
     "file": "./core/qv/processMessages",
     "template": "ProcessMessages",
-    "params": [10, 2, 1, 2],
+    "params": [10, 20, 2],
     "pubs": ["inputHash"]
   },
-  "ProcessMessagesNonQv_10-2-1-2_test": {
+  "ProcessMessagesNonQv_10-20-2_test": {
     "file": "./core/non-qv/processMessages",
     "template": "ProcessMessagesNonQv",
-    "params": [10, 2, 1, 2],
+    "params": [10, 20, 2],
     "pubs": ["inputHash"]
   },
   "TallyVotes_10-1-2_test": {

circuits/circom/core/non-qv/processMessages.circom

@@ -15,27 +15,22 @@ include "../../trees/incrementalQuinaryTree.circom";
 
 /**
  * Proves the correctness of processing a batch of MACI messages.
- * The msgBatchDepth parameter is known as msgSubtreeDepth and indicates the depth 
- * of the shortest tree that can fit all the messages in a batch.
  * This template does not support Quadratic Voting (QV).
  */
  template ProcessMessagesNonQv(
     stateTreeDepth,
-    msgTreeDepth,
-    msgBatchDepth,
+    batchSize,
     voteOptionTreeDepth
 ) {
     // Must ensure that the trees have a valid structure.
     assert(stateTreeDepth > 0);
-    assert(msgBatchDepth > 0);
+    assert(batchSize > 0);
     assert(voteOptionTreeDepth > 0);
-    assert(msgTreeDepth >= msgBatchDepth);
 
     // Default for IQT (quinary trees).
-    var MESSAGE_TREE_ARITY = 5;
+    var VOTE_OPTION_TREE_ARITY = 5;
     // Default for Binary trees.
     var STATE_TREE_ARITY = 2;
-    var batchSize = MESSAGE_TREE_ARITY ** msgBatchDepth;
     var MSG_LENGTH = 10;
     var PACKED_CMD_LENGTH = 4;
     var STATE_LEAF_LENGTH = 4;
@@ -59,14 +54,12 @@ include "../../trees/incrementalQuinaryTree.circom";
     signal numSignUps;
     // Number of options for this poll.
     signal maxVoteOptions;
-    // Time when the poll ends.
-    signal input pollEndTimestamp;
-    // The existing message tree root.
-    signal input msgRoot;
+    // Value of chainHash at beginning of batch
+    signal input inputBatchHash;
+    // Value of chainHash at end of batch
+    signal input outputBatchHash;
     // The messages.
     signal input msgs[batchSize][MSG_LENGTH];
-    // Sibling messages.
-    signal input msgSubrootPathElements[msgTreeDepth - msgBatchDepth][MESSAGE_TREE_ARITY - 1];
     // The coordinator's private key.
     signal input coordPrivKey;
     // The cooordinator's public key (derived from the contract).
@@ -104,16 +97,16 @@ include "../../trees/incrementalQuinaryTree.circom";
     signal input currentBallotsPathElements[batchSize][stateTreeDepth][STATE_TREE_ARITY - 1];
     // Intermediate vote weights.
     signal input currentVoteWeights[batchSize];
-    signal input currentVoteWeightsPathElements[batchSize][voteOptionTreeDepth][MESSAGE_TREE_ARITY - 1];
+    signal input currentVoteWeightsPathElements[batchSize][voteOptionTreeDepth][VOTE_OPTION_TREE_ARITY - 1];
 
     // nb. The messages are processed in REVERSE order.
     // Therefore, the index of the first message to process does not match the index of the
     // first message (e.g., [msg1, msg2, msg3] => first message to process has index 3).
 
-    // The index of the first message leaf in the batch, inclusive.
+    // The index of the first message in the batch, inclusive.
     signal batchStartIndex;
 
-    // The index of the last message leaf in the batch to process, exclusive.
+    // The index of the last message in the batch to process, exclusive.
     // This value may be less than batchStartIndex + batchSize if this batch is
     // the last batch and the total number of messages is not a multiple of the batch size.
     signal batchEndIndex;
@@ -135,16 +128,15 @@ include "../../trees/incrementalQuinaryTree.circom";
     var (
         computedMaxVoteOptions, 
         computedNumSignUps, 
-        computedBatchStartIndex, 
+        computedBatchStartIndex,
         computedBatchEndIndex, 
         computedHash
     ) = ProcessMessagesInputHasher()(
         packedVals,
         coordPubKey,
-        msgRoot,
+        outputBatchHash,
         currentSbCommitment,
         newSbCommitment,
-        pollEndTimestamp,
         actualStateTreeDepth
     );
 
@@ -159,7 +151,7 @@ include "../../trees/incrementalQuinaryTree.circom";
     //  ----------------------------------------------------------------------- 
     // 0. Ensure that the maximum vote options signal is valid and if
     // the maximum users signal is valid.
-    var maxVoValid = LessEqThan(32)([maxVoteOptions, MESSAGE_TREE_ARITY ** voteOptionTreeDepth]);
+    var maxVoValid = LessEqThan(32)([maxVoteOptions, VOTE_OPTION_TREE_ARITY ** voteOptionTreeDepth]);
     maxVoValid === 1;
 
     // Check numSignUps <= the max number of users (i.e., number of state leaves
@@ -169,50 +161,23 @@ include "../../trees/incrementalQuinaryTree.circom";
 
     // Hash each Message to check their existence in the Message tree.
     var computedMessageHashers[batchSize];
+    var computedHashes[batchSize];
+    var chainHash[batchSize + 1];
+    chainHash[0] = inputBatchHash;
     for (var i = 0; i < batchSize; i++) {
         computedMessageHashers[i] = MessageHasher()(msgs[i], encPubKeys[i]);
+        var batchStartIndexValid = SafeLessThan(32)([batchStartIndex + i, batchEndIndex]);
+        computedHashes[i] = PoseidonHasher(2)([chainHash[i], computedMessageHashers[i]]);
+
+        chainHash[i + 1] = Mux1()([chainHash[i], computedHashes[i]], batchStartIndexValid);
     }
 
     // If batchEndIndex - batchStartIndex < batchSize, the remaining
     // message hashes should be the zero value.
     // e.g. [m, z, z, z, z] if there is only 1 real message in the batch
     // This makes possible to have a batch of messages which is only partially full.
-    var computedLeaves[batchSize];
-    var computedPathElements[msgTreeDepth - msgBatchDepth][MESSAGE_TREE_ARITY - 1];
-    var computedPathIndex[msgTreeDepth - msgBatchDepth];
 
-    for (var i = 0; i < batchSize; i++) {
-        var batchStartIndexValid = SafeLessThan(32)([batchStartIndex + i, batchEndIndex]);
-        computedLeaves[i] = Mux1()([msgTreeZeroValue, computedMessageHashers[i]], batchStartIndexValid);
-    }
-
-    for (var i = 0; i < msgTreeDepth - msgBatchDepth; i++) {
-        for (var j = 0; j < MESSAGE_TREE_ARITY - 1; j++) {
-            computedPathElements[i][j] = msgSubrootPathElements[i][j];
-        }
-    }
-
-    // Computing the path_index values. Since msgBatchLeavesExists tests
-    // the existence of a subroot, the length of the proof correspond to the last 
-    // n elements of a proof from the root to a leaf, where n = msgTreeDepth - msgBatchDepth.
-    // e.g. if batchStartIndex = 25, msgTreeDepth = 4, msgBatchDepth = 2, then path_index = [1, 0].
-    var computedMsgBatchPathIndices[msgTreeDepth] = QuinGeneratePathIndices(msgTreeDepth)(batchStartIndex);
-
-    for (var i = msgBatchDepth; i < msgTreeDepth; i++) {
-        computedPathIndex[i - msgBatchDepth] = computedMsgBatchPathIndices[i];
-    }
-
-    // Check whether each message exists in the Message tree.
-    // Otherwise, throws (needs constraint to prevent such a proof).
-    // To save constraints, compute the subroot of the messages and check
-    // whether the subroot is a member of the message tree. This means that
-    // batchSize must be the message tree arity raised to some power (e.g. 5 ^ n).
-    QuinBatchLeavesExists(msgTreeDepth, msgBatchDepth)(
-        msgRoot,
-        computedLeaves,
-        computedPathIndex,
-        computedPathElements   
-    );
+    chainHash[batchSize] === outputBatchHash;
 
     // Decrypt each Message to a Command.
     // MessageToCommand derives the ECDH shared key from the coordinator's
@@ -274,7 +239,7 @@ include "../../trees/incrementalQuinaryTree.circom";
         // Process as vote type message.
         var currentStateLeavesPathElement[stateTreeDepth][STATE_TREE_ARITY - 1];
         var currentBallotPathElement[stateTreeDepth][STATE_TREE_ARITY - 1];
-        var currentVoteWeightsPathElement[voteOptionTreeDepth][MESSAGE_TREE_ARITY - 1];
+        var currentVoteWeightsPathElement[voteOptionTreeDepth][VOTE_OPTION_TREE_ARITY - 1];
 
         for (var j = 0; j < stateTreeDepth; j++) {
             for (var k = 0; k < STATE_TREE_ARITY - 1; k++) {
@@ -284,15 +249,14 @@ include "../../trees/incrementalQuinaryTree.circom";
         }
 
         for (var j = 0; j < voteOptionTreeDepth; j++) {
-            for (var k = 0; k < MESSAGE_TREE_ARITY - 1; k++) {
+            for (var k = 0; k < VOTE_OPTION_TREE_ARITY - 1; k++) {
                 currentVoteWeightsPathElement[j][k] = currentVoteWeightsPathElements[i][j][k];
             }
         }
 
         (computedNewVoteStateRoot[i], computedNewVoteBallotRoot[i]) = ProcessOneNonQv(stateTreeDepth, voteOptionTreeDepth)(
             numSignUps,
             maxVoteOptions,
-            pollEndTimestamp,
             stateRoots[i + 1],
             ballotRoots[i + 1],
             actualStateTreeDepth,
@@ -336,7 +300,7 @@ template ProcessOneNonQv(stateTreeDepth, voteOptionTreeDepth) {
     var BALLOT_LENGTH = 2;
     var MSG_LENGTH = 10;
     var PACKED_CMD_LENGTH = 4;
-    var MESSAGE_TREE_ARITY = 5;
+    var VOTE_OPTION_TREE_ARITY = 5;
     var STATE_TREE_ARITY = 2;
     var BALLOT_NONCE_IDX = 0;
     // Ballot vote option (VO) root index.
@@ -355,7 +319,6 @@ template ProcessOneNonQv(stateTreeDepth, voteOptionTreeDepth) {
     // Inputs representing the message and the current state.
     signal input numSignUps;
     signal input maxVoteOptions;
-    signal input pollEndTimestamp;
 
     // The current value of the state tree root.
     signal input currentStateRoot;
@@ -375,7 +338,7 @@ template ProcessOneNonQv(stateTreeDepth, voteOptionTreeDepth) {
 
     // The current vote weight and related path elements.
     signal input currentVoteWeight;
-    signal input currentVoteWeightsPathElements[voteOptionTreeDepth][MESSAGE_TREE_ARITY - 1];
+    signal input currentVoteWeightsPathElements[voteOptionTreeDepth][VOTE_OPTION_TREE_ARITY - 1];
 
     // Inputs related to the command being processed.
     signal input cmdStateIndex;
@@ -409,7 +372,6 @@ template ProcessOneNonQv(stateTreeDepth, voteOptionTreeDepth) {
         [stateLeaf[STATE_LEAF_PUB_X_IDX], stateLeaf[STATE_LEAF_PUB_Y_IDX]],
         stateLeaf[STATE_LEAF_VOICE_CREDIT_BALANCE_IDX],
         stateLeaf[STATE_LEAF_TIMESTAMP_IDX],
-        pollEndTimestamp,
         ballot[BALLOT_NONCE_IDX],
         currentVoteWeight,
         cmdStateIndex,