feat(contracts): add total spent to tally

- [x] Update add tally results method signature - [x] Compatibility fixes - [x] Add total spent to tally contract
privacy-scaling-explorations · Oct 22, 2024 · ac206f3 · ac206f3
1 parent 971fe9c
commit ac206f3
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Showing 4 changed files with 60 additions and 6 deletions.
diff --git a/packages/cli/ts/commands/proveOnChain.ts b/packages/cli/ts/commands/proveOnChain.ts
@@ -383,7 +383,10 @@ export const proveOnChain = async ({
         tallyData.results.tally.map((_, index) => index),
         tallyResults,
         tallyResultProofs,
+        tallyData.totalSpentVoiceCredits.spent,
+        tallyData.totalSpentVoiceCredits.salt,
         tallyData.results.salt,
+        tallyData.results.commitment,
         tallyData.totalSpentVoiceCredits.commitment,
         tallyData.perVOSpentVoiceCredits?.commitment ?? 0n,
       )

diff --git a/packages/contracts/contracts/Tally.sol b/packages/contracts/contracts/Tally.sol
@@ -66,6 +66,9 @@ contract Tally is Ownable, SnarkCommon, CommonUtilities, Hasher, DomainObjs, ITa
   // The total tally results number
   uint256 public totalTallyResults;
 
+  // spent field retrieved in the totalSpentVoiceCredits object
+  uint256 public totalSpent;
+
   /// @notice custom errors
   error ProcessingNotComplete();
   error InvalidTallyVotesProof();
@@ -75,6 +78,7 @@ contract Tally is Ownable, SnarkCommon, CommonUtilities, Hasher, DomainObjs, ITa
   error TallyBatchSizeTooLarge();
   error NotSupported();
   error VotesNotTallied();
+  error IncorrectSpentVoiceCredits();
 
   /// @notice Create a new Tally contract
   /// @param _verifier The Verifier contract
@@ -365,17 +369,22 @@ contract Tally is Ownable, SnarkCommon, CommonUtilities, Hasher, DomainObjs, ITa
    * @param _voteOptionIndices Vote option index.
    * @param _tallyResults The results of vote tally for the recipients.
    * @param _tallyResultProofs Proofs of correctness of the vote tally results.
+   * @param _totalSpent spent field retrieved in the totalSpentVoiceCredits object
    * @param _tallyResultSalt the respective salt in the results object in the tally.json
-   * @param _spentVoiceCreditsHashes hashLeftRight(number of spent voice credits, spent salt)
-   * @param _perVOSpentVoiceCreditsHashes hashLeftRight(merkle root of the no spent voice credits per vote option, perVOSpentVoiceCredits salt)
+   * @param _newResultsCommitment The salted commitment of the vote tally for this batch of leaves plus the vote tally from currentResults
+   * @param _spentVoiceCreditsHash hashLeftRight(number of spent voice credits, spent salt)
+   * @param _perVOSpentVoiceCreditsHash hashLeftRight(merkle root of the no spent voice credits per vote option, perVOSpentVoiceCredits salt)
    */
   function addTallyResults(
     uint256[] calldata _voteOptionIndices,
     uint256[] calldata _tallyResults,
     uint256[][][] calldata _tallyResultProofs,
+    uint256 _totalSpent,
+    uint256 _totalSpentSalt,
     uint256 _tallyResultSalt,
-    uint256 _spentVoiceCreditsHashes,
-    uint256 _perVOSpentVoiceCreditsHashes
+    uint256 _newResultsCommitment,
+    uint256 _spentVoiceCreditsHash,
+    uint256 _perVOSpentVoiceCreditsHash
   ) public virtual onlyOwner {
     if (!isTallied()) {
       revert VotesNotTallied();
@@ -390,15 +399,28 @@ contract Tally is Ownable, SnarkCommon, CommonUtilities, Hasher, DomainObjs, ITa
         _tallyResults[i],
         _tallyResultProofs[i],
         _tallyResultSalt,
-        _spentVoiceCreditsHashes,
-        _perVOSpentVoiceCreditsHashes,
+        _spentVoiceCreditsHash,
+        _perVOSpentVoiceCreditsHash,
         voteOptionTreeDepth
       );
 
       unchecked {
         i++;
       }
     }
+
+    bool verified = verifySpentVoiceCredits(
+      _totalSpent,
+      _totalSpentSalt,
+      _newResultsCommitment,
+      _perVOSpentVoiceCreditsHash
+    );
+
+    if (!verified) {
+      revert IncorrectSpentVoiceCredits();
+    }
+
+    totalSpent = _totalSpent;
   }
 
   /**

diff --git a/packages/contracts/tasks/helpers/Prover.ts b/packages/contracts/tasks/helpers/Prover.ts
@@ -321,7 +321,10 @@ export class Prover {
         tallyData.results.tally.map((_, index) => index),
         tallyResults,
         tallyResultProofs,
+        tallyData.totalSpentVoiceCredits.spent,
+        tallyData.totalSpentVoiceCredits.salt,
         tallyData.results.salt,
+        tallyData.results.commitment,
         tallyData.totalSpentVoiceCredits.commitment,
         tallyData.perVOSpentVoiceCredits?.commitment ?? 0n,
       )

diff --git a/packages/contracts/tests/Tally.test.ts b/packages/contracts/tests/Tally.test.ts
@@ -320,7 +320,10 @@ describe("TallyVotes", () => {
           tallyData.results.tally.map((_, index) => index),
           tallyData.results.tally,
           tallyResultProofs,
+          tallyData.totalSpentVoiceCredits.spent,
+          tallyData.totalSpentVoiceCredits.salt,
           tallyData.results.salt,
+          tallyData.results.commitment,
           tallyData.totalSpentVoiceCredits.commitment,
           0n,
         ),
@@ -372,12 +375,29 @@ describe("TallyVotes", () => {
 
       const indices = tallyData.results.tally.map((_, index) => index);
 
+      await expect(
+        tallyContract.addTallyResults(
+          indices,
+          tallyData.results.tally,
+          tallyResultProofs,
+          0n,
+          0n,
+          tallyData.results.salt,
+          0n,
+          tallyData.totalSpentVoiceCredits.commitment,
+          newPerVOSpentVoiceCreditsCommitment,
+        ),
+      ).to.be.revertedWithCustomError(tallyContract, "IncorrectSpentVoiceCredits");
+
       await tallyContract
         .addTallyResults(
           indices,
           tallyData.results.tally,
           tallyResultProofs,
+          tallyData.totalSpentVoiceCredits.spent,
+          tallyData.totalSpentVoiceCredits.salt,
           tallyData.results.salt,
+          tallyData.results.commitment,
           tallyData.totalSpentVoiceCredits.commitment,
           newPerVOSpentVoiceCreditsCommitment,
         )
@@ -394,7 +414,10 @@ describe("TallyVotes", () => {
           indices,
           tallyData.results.tally,
           tallyResultProofs,
+          tallyData.totalSpentVoiceCredits.spent,
+          tallyData.totalSpentVoiceCredits.salt,
           tallyData.results.salt,
+          tallyData.results.commitment,
           tallyData.totalSpentVoiceCredits.commitment,
           newPerVOSpentVoiceCreditsCommitment,
         )
@@ -436,7 +459,10 @@ describe("TallyVotes", () => {
           tallyData.results.tally.map((_, index) => index),
           tallyData.results.tally,
           tallyResultProofs,
+          tallyData.totalSpentVoiceCredits.spent,
+          tallyData.totalSpentVoiceCredits.salt,
           tallyData.results.salt,
+          tallyData.results.commitment,
           tallyData.totalSpentVoiceCredits.commitment,
           0n,
         ),