remove toggleDeposits

contracts/Mixer.sol

@@ -24,12 +24,9 @@ contract Mixer is MerkleTreeWithHistory {
   mapping(bytes32 => bool) public commitments;
   IVerifier public verifier;
 
-  // operator can
+  // operator can update snark verification key
-  //  - disable new deposits in case of emergency
+  // after the final trusted setup ceremony operator rights are supposed to be transferred to zero address
-  //  - update snark verification key until this ability is permanently disabled
   address public operator;
-  bool public isDepositsDisabled;
-  bool public isVerifierUpdateDisabled;
   modifier onlyOperator {
     require(msg.sender == operator, "Only operator can call this function.");
     _;
@@ -62,7 +59,6 @@ contract Mixer is MerkleTreeWithHistory {
     @param _commitment the note commitment, which is PedersenHash(nullifier + secret)
   */
   function deposit(bytes32 _commitment) external payable {
-    require(!isDepositsDisabled, "deposits are disabled");
     require(!commitments[_commitment], "The commitment has been submitted");
 
     uint32 insertedIndex = _insert(_commitment);
@@ -102,31 +98,14 @@ contract Mixer is MerkleTreeWithHistory {
     return nullifierHashes[_nullifierHash];
   }
 
-  /**
-    @dev Allow operator to temporarily disable new deposits. This is needed to protect users funds in case a vulnerability is discovered.
-    It does not affect existing deposits.
-  */
-  function toggleDeposits(bool _state) external onlyOperator {
-    isDepositsDisabled = _state;
-  }
-
   /**
     @dev allow operator to update SNARK verification keys. This is needed to update keys after the final trusted setup ceremony is held.
-    After that operator is supposed to permanently disable this ability.
+    After that operator rights are supposed to be transferred to zero address
   */
   function updateVerifier(address _newVerifier) external onlyOperator {
-    require(!isVerifierUpdateDisabled, "Verifier updates have been disabled.");
     verifier = IVerifier(_newVerifier);
   }
 
-  /**
-    @dev an option for operator to permanently disable verification keys update ability.
-    This is supposed to be called after the final trusted setup ceremony is held.
-  */
-  function disableVerifierUpdate() external onlyOperator {
-    isVerifierUpdateDisabled = true;
-  }
-
   /** @dev operator can change his address */
   function changeOperator(address _newOperator) external onlyOperator {
     operator = _newOperator;

test/ETHMixer.test.js

@@ -118,21 +118,6 @@ contract('ETHMixer', accounts => {
       logs[0].args.leafIndex.should.be.eq.BN(1)
     })
 
-    it('should not deposit if disabled', async () => {
-      let commitment = toFixedHex(42);
-      (await mixer.isDepositsDisabled()).should.be.equal(false)
-      const err = await mixer.toggleDeposits(true, { from: accounts[1] }).should.be.rejected
-      err.reason.should.be.equal('Only operator can call this function.')
-      await mixer.toggleDeposits(false, { from: sender });
-      (await mixer.isDepositsDisabled()).should.be.equal(false)
-      await mixer.toggleDeposits(true, { from: sender });
-      (await mixer.isDepositsDisabled()).should.be.equal(true)
-      await mixer.toggleDeposits(true, { from: sender });
-      (await mixer.isDepositsDisabled()).should.be.equal(true)
-      let error = await mixer.deposit(commitment, { value, from: sender }).should.be.rejected
-      error.reason.should.be.equal('deposits are disabled')
-    })
-
     it('should throw if there is a such commitment', async () => {
       const commitment = toFixedHex(42)
       await mixer.deposit(commitment, { value, from: sender }).should.be.fulfilled
@@ -557,38 +542,6 @@ contract('ETHMixer', accounts => {
     })
   })
 
-  describe('#disableVerifierUpdate', () => {
-    it('should work', async () => {
-      let operator = await mixer.operator()
-      operator.should.be.equal(sender)
-
-      let isVerifierUpdateDisabled = await mixer.isVerifierUpdateDisabled()
-      isVerifierUpdateDisabled.should.be.equal(false)
-
-      await mixer.disableVerifierUpdate().should.be.fulfilled
-
-      const newValue = await mixer.isVerifierUpdateDisabled()
-      newValue.should.be.equal(true)
-    })
-
-    it('cannot update verifier after this function is called', async () => {
-      let operator = await mixer.operator()
-      operator.should.be.equal(sender)
-
-      let isVerifierUpdateDisabled = await mixer.isVerifierUpdateDisabled()
-      isVerifierUpdateDisabled.should.be.equal(false)
-
-      await mixer.disableVerifierUpdate().should.be.fulfilled
-
-      const newValue = await mixer.isVerifierUpdateDisabled()
-      newValue.should.be.equal(true)
-
-      const newVerifier = accounts[7]
-      const error = await mixer.updateVerifier(newVerifier).should.be.rejected
-      error.reason.should.be.equal('Verifier updates have been disabled.')
-    })
-  })
-
   afterEach(async () => {
     await revertSnapshot(snapshotId.result)
     // eslint-disable-next-line require-atomic-updates