diff --git a/cli/ts/deployPoll.ts b/cli/ts/deployPoll.ts
index 50b9b3782e..f71ed05dca 100644
--- a/cli/ts/deployPoll.ts
+++ b/cli/ts/deployPoll.ts
@@ -2,7 +2,9 @@ const { ethers } = require('hardhat')
 import {
     parseArtifact,
     deployVerifier,
+    deployMessageProcessor,
     deployTally,
+    deploySubsidy,
     deployContract,
     getDefaultSigner,
 } from 'maci-contracts'
@@ -173,13 +175,13 @@ const deployPoll = async (args: any) => {
     // Deploy a MessageProcessor contract
     const verifierContract = await deployVerifier(true)
     console.log('Verifier:', verifierContract.address)
-    const mpContract = await deployContract('MessageProcessor', true, verifierContract.address)
+    const mpContract = await deployMessageProcessor(verifierContract.address, contractAddrs['PoseidonT3'],contractAddrs['PoseidonT4'],contractAddrs['PoseidonT5'],contractAddrs['PoseidonT6'])
     await mpContract.deployTransaction.wait()
 
     const tallyContract = await deployTally(verifierContract.address, contractAddrs['PoseidonT3'],contractAddrs['PoseidonT4'],contractAddrs['PoseidonT5'],contractAddrs['PoseidonT6'])
     await tallyContract.deployTransaction.wait()
 
-    const subsidyContract = await deployContract('Subsidy', true, verifierContract.address)
+    const subsidyContract = await deploySubsidy(verifierContract.address, contractAddrs['PoseidonT3'],contractAddrs['PoseidonT4'],contractAddrs['PoseidonT5'],contractAddrs['PoseidonT6'])
     await subsidyContract.deployTransaction.wait()
 
     const [ maciAbi ] = parseArtifact('MACI')
diff --git a/contracts/contracts/MessageProcessor.sol b/contracts/contracts/MessageProcessor.sol
index e155d915e8..68c350890e 100644
--- a/contracts/contracts/MessageProcessor.sol
+++ b/contracts/contracts/MessageProcessor.sol
@@ -6,14 +6,13 @@ import {IMACI} from "./IMACI.sol";
 import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 import {Poll} from "./Poll.sol";
 import {SnarkCommon} from "./crypto/SnarkCommon.sol";
+import {Hasher} from "./crypto/Hasher.sol";
 import {CommonUtilities} from "./utilities/Utility.sol";
 import {Verifier} from "./crypto/Verifier.sol";
 import {VkRegistry} from "./VkRegistry.sol";
 
-contract MessageProcessor is Ownable, SnarkCommon, CommonUtilities {
+contract MessageProcessor is Ownable, SnarkCommon, CommonUtilities, Hasher {
 
-    string constant ERROR_VOTING_PERIOD_PASSED = "ProcessE01";
-    string constant ERROR_VOTING_PERIOD_NOT_PASSED = "ProcessE02";
     string constant ERROR_NO_MORE_MESSAGES = "ProcessE03";
     string constant ERROR_STATE_AQ_NOT_MERGED = "ProcessE04";
     string constant ERROR_MESSAGE_AQ_NOT_MERGED = "ProcessE04";
@@ -38,14 +37,6 @@ contract MessageProcessor is Ownable, SnarkCommon, CommonUtilities {
         verifier = _verifier;
     }
 
-    modifier votingPeriodOver(Poll _poll) {
-        (uint256 deployTime, uint256 duration) = _poll
-            .getDeployTimeAndDuration();
-        // Require that the voting period is over
-        uint256 secondsPassed = block.timestamp - deployTime;
-        require(secondsPassed > duration, ERROR_VOTING_PERIOD_NOT_PASSED);
-        _;
-    }
 
     /*
      * Update the Poll's currentSbCommitment if the proof is valid.
@@ -58,7 +49,8 @@ contract MessageProcessor is Ownable, SnarkCommon, CommonUtilities {
         Poll _poll,
         uint256 _newSbCommitment,
         uint256[8] memory _proof
-    ) public onlyOwner votingPeriodOver(_poll) {
+    ) public onlyOwner {
+        _votingPeriodOver(_poll);
         // There must be unprocessed messages
         require(!processingComplete, ERROR_NO_MORE_MESSAGES);
 
diff --git a/contracts/contracts/Subsidy.sol b/contracts/contracts/Subsidy.sol
index d8b8da9437..b662d78147 100644
--- a/contracts/contracts/Subsidy.sol
+++ b/contracts/contracts/Subsidy.sol
@@ -6,6 +6,7 @@ import {MessageProcessor} from "./MessageProcessor.sol";
 import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
 import {Poll} from "./Poll.sol";
 import {SnarkCommon} from "./crypto/SnarkCommon.sol";
+import {Hasher} from "./crypto/Hasher.sol";
 import {CommonUtilities} from "./utilities/Utility.sol";
 import {Verifier} from "./crypto/Verifier.sol";
 import {VkRegistry} from "./VkRegistry.sol";
@@ -13,6 +14,7 @@ import {VkRegistry} from "./VkRegistry.sol";
 contract Subsidy is
     Ownable,
     CommonUtilities,
+    Hasher,
     SnarkCommon
 {
 
@@ -23,11 +25,10 @@ contract Subsidy is
     uint256 public subsidyCommitment;
 
     // Error codes
-    string constant ERROR_VOTING_PERIOD_NOT_PASSED = "SubsidyE01";
-    string constant ERROR_PROCESSING_NOT_COMPLETE = "SubsidyE02";
-    string constant ERROR_INVALID_SUBSIDY_PROOF = "SubsidyE03";
-    string constant ERROR_ALL_SUBSIDY_CALCULATED = "SubsidyE04";
-    string constant ERROR_VK_NOT_SET = "SubsidyE05";
+    error PROCESSING_NOT_COMPLETE();
+    error INVALID_SUBSIDY_PROOF();
+    error ALL_SUBSIDY_CALCULATED();
+    error VK_NOT_SET();
 
     Verifier public verifier;
 
@@ -35,20 +36,13 @@ contract Subsidy is
         verifier = _verifier;
     }
 
-    modifier votingPeriodOver(Poll _poll) {
-        (uint256 deployTime, uint256 duration) = _poll
-            .getDeployTimeAndDuration();
-        // Require that the voting period is over
-        uint256 secondsPassed = block.timestamp - deployTime;
-        require(secondsPassed > duration, ERROR_VOTING_PERIOD_NOT_PASSED);
-        _;
-    }
-
     // TODO: make sure correct mp address is passed or change to private function
     // TODO: reuse subsidy.sol for multiple polls
     function updateSbCommitment(MessageProcessor _mp) public {
         // Require that all messages have been processed
-        require(_mp.processingComplete(), ERROR_PROCESSING_NOT_COMPLETE);
+        if (!_mp.processingComplete()) {
+            revert PROCESSING_NOT_COMPLETE();
+        }
         if (sbCommitment == 0) {
             sbCommitment = _mp.sbCommitment();
         }
@@ -87,7 +81,8 @@ contract Subsidy is
         MessageProcessor _mp,
         uint256 _newSubsidyCommitment,
         uint256[8] memory _proof
-    ) public onlyOwner votingPeriodOver(_poll) {
+    ) public onlyOwner {
+        _votingPeriodOver(_poll);
         updateSbCommitment(_mp);
 
         (uint8 intStateTreeDepth, , , uint8 voteOptionTreeDepth) = _poll
@@ -97,14 +92,9 @@ contract Subsidy is
         uint256 numLeaves = numSignUps + 1;
 
         // Require that there are unfinished ballots left
-        require(
-            rbi * subsidyBatchSize <= numLeaves,
-            ERROR_ALL_SUBSIDY_CALCULATED
-        );
-        require(
-            cbi * subsidyBatchSize <= numLeaves,
-            ERROR_ALL_SUBSIDY_CALCULATED
-        );
+        if (rbi * subsidyBatchSize > numLeaves) {
+            revert ALL_SUBSIDY_CALCULATED();
+        }
 
         bool isValid = verifySubsidyProof(
             _poll,
@@ -112,7 +102,9 @@ contract Subsidy is
             numSignUps,
             _newSubsidyCommitment
         );
-        require(isValid, ERROR_INVALID_SUBSIDY_PROOF);
+        if (!isValid) {
+            revert INVALID_SUBSIDY_PROOF();
+        }
         subsidyCommitment = _newSubsidyCommitment;
         increaseSubsidyIndex(subsidyBatchSize, numLeaves);
     }
@@ -138,7 +130,9 @@ contract Subsidy is
             .treeDepths();
         (VkRegistry vkRegistry, IMACI maci, , ) = _poll.extContracts();
 
-        require(address(vkRegistry) != address(0), ERROR_VK_NOT_SET);
+        if (address(vkRegistry) == address(0)) {
+            revert VK_NOT_SET();
+        }
 
         // Get the verifying key
         VerifyingKey memory vk = vkRegistry.getSubsidyVk(
diff --git a/contracts/contracts/Tally.sol b/contracts/contracts/Tally.sol
index 2d2023e03d..dda8be6609 100644
--- a/contracts/contracts/Tally.sol
+++ b/contracts/contracts/Tally.sol
@@ -10,15 +10,16 @@ import {MessageProcessor} from "./MessageProcessor.sol";
 import {SnarkCommon} from "./crypto/SnarkCommon.sol";
 import {Verifier} from "./crypto/Verifier.sol";
 import {VkRegistry} from "./VkRegistry.sol";
+import {CommonUtilities} from "./utilities/Utility.sol";
 
 
 contract Tally is
     Ownable,
     SnarkCommon,
+    CommonUtilities,
     Hasher
 {
     // Error codes
-    error VOTING_PERIOD_NOT_PASSED();
     error PROCESSING_NOT_COMPLETE();
     error INVALID_TALLY_VOTES_PROOF();
     error ALL_BALLOTS_TALLIED();
@@ -50,16 +51,6 @@ contract Tally is
         verifier = _verifier;
     }
 
-    modifier votingPeriodOver(Poll _poll) {
-        (uint256 deployTime, uint256 duration) = _poll
-            .getDeployTimeAndDuration();
-        // Require that the voting period is over
-        uint256 secondsPassed = block.timestamp - deployTime;
-        if (secondsPassed <= duration ) {
-            revert VOTING_PERIOD_NOT_PASSED();
-        }
-        _;
-    }
 
     /*
      * @notice Pack the batch start index and number of signups into a 100-bit value.
@@ -128,7 +119,8 @@ contract Tally is
         MessageProcessor _mp,
         uint256 _newTallyCommitment,
         uint256[8] memory _proof
-    ) public onlyOwner votingPeriodOver(_poll) {
+    ) public onlyOwner {
+        _votingPeriodOver(_poll);
         updateSbCommitment(_mp);
 
         (, uint256 tallyBatchSize, ) = _poll.batchSizes();
diff --git a/contracts/contracts/utilities/Utility.sol b/contracts/contracts/utilities/Utility.sol
index 99b3fb62bc..5abf2e0bde 100644
--- a/contracts/contracts/utilities/Utility.sol
+++ b/contracts/contracts/utilities/Utility.sol
@@ -3,20 +3,20 @@ pragma solidity ^0.8.10;
 import {DomainObjs, IPubKey, IMessage} from "../DomainObjs.sol";
 import {Hasher} from "../crypto/Hasher.sol";
 import {SnarkConstants} from "../crypto/SnarkConstants.sol";
+import {Poll} from "../Poll.sol";
 
 
-contract CommonUtilities is SnarkConstants {
-     /*
-     * Hashes an array of values using SHA256 and returns its modulo with the
-     * snark scalar field. This function is used to hash inputs to circuits,
-     * where said inputs would otherwise be public inputs. As such, the only
-     * public input to the circuit is the SHA256 hash, and all others are
-     * private inputs. The circuit will verify that the hash is valid. Doing so
-     * saves a lot of gas during verification, though it makes the circuit take
-     * up more constraints.
-     */
-    function sha256Hash(uint256[] memory array) public pure returns (uint256) {
-        return uint256(sha256(abi.encodePacked(array))) % SNARK_SCALAR_FIELD;
+contract CommonUtilities {
+     error VOTING_PERIOD_NOT_PASSED();
+    // common function for MessageProcessor, Tally and Subsidy
+    function _votingPeriodOver(Poll _poll) internal {
+        (uint256 deployTime, uint256 duration) = _poll
+            .getDeployTimeAndDuration();
+        // Require that the voting period is over
+        uint256 secondsPassed = block.timestamp - deployTime;
+        if (secondsPassed <= duration ) {
+            revert VOTING_PERIOD_NOT_PASSED();
+        }
     }
 }
 
diff --git a/contracts/ts/deploy.ts b/contracts/ts/deploy.ts
index e18e68bde6..bba910a84c 100644
--- a/contracts/ts/deploy.ts
+++ b/contracts/ts/deploy.ts
@@ -224,6 +224,32 @@ const getFeeData = async (): Promise<any> => {
     return await signer.provider.getFeeData()
 }
 
+const deployMessageProcessor = async (
+    verifierAddress,
+    poseidonT3Address,
+    poseidonT4Address,
+    poseidonT5Address,
+    poseidonT6Address,
+    quiet = false
+    ) => {
+    // Link Poseidon contracts to MessageProcessor
+    const mpFactory = await linkPoseidonLibraries(
+            'MessageProcessor',
+            poseidonT3Address,
+            poseidonT4Address,
+            poseidonT5Address,
+            poseidonT6Address,
+            quiet
+        )
+    const mpContract = await deployContractWithLinkedLibraries(
+        mpFactory,
+        'MessageProcessor',
+        quiet,
+        verifierAddress,
+    )
+    return mpContract
+}
+
 const deployTally = async (
     verifierAddress,
     poseidonT3Address,
@@ -250,6 +276,32 @@ const deployTally = async (
     return tallyContract
 }
 
+const deploySubsidy = async (
+    verifierAddress,
+    poseidonT3Address,
+    poseidonT4Address,
+    poseidonT5Address,
+    poseidonT6Address,
+    quiet = false
+    ) => {
+    // Link Poseidon contracts to Subsidy
+    const subsidyFactory = await linkPoseidonLibraries(
+            'Subsidy',
+            poseidonT3Address,
+            poseidonT4Address,
+            poseidonT5Address,
+            poseidonT6Address,
+            quiet
+        )
+    const subsidyContract = await deployContractWithLinkedLibraries(
+        subsidyFactory,
+        'Subsidy',
+        quiet,
+        verifierAddress,
+    )
+    return subsidyContract
+}
+
 const deployMaci = async (
     signUpTokenGatekeeperContractAddress: string,
     initialVoiceCreditBalanceAddress: string,
@@ -352,7 +404,9 @@ export {
     deployTopupCredit,
     deployVkRegistry,
     deployMaci,
+    deployMessageProcessor,
     deployTally,
+    deploySubsidy,
     deploySignupToken,
     deploySignupTokenGatekeeper,
     deployConstantInitialVoiceCreditProxy,
diff --git a/contracts/ts/index.ts b/contracts/ts/index.ts
index 5e086b9469..8839811515 100644
--- a/contracts/ts/index.ts
+++ b/contracts/ts/index.ts
@@ -4,7 +4,9 @@ import {
     deployTopupCredit,
     deployVkRegistry,
     deployMaci,
+    deployMessageProcessor,
     deployTally,
+    deploySubsidy,
     deployContract,
     deploySignupToken,
     deploySignupTokenGatekeeper,
@@ -33,7 +35,9 @@ export {
     deployTopupCredit,
     deployVkRegistry,
     deployMaci,
+    deployMessageProcessor,
     deployTally,
+    deploySubsidy,
     deployContract,
     deployMockVerifier,
     deploySignupToken,