diff --git a/contracts/decryptionOracle/DecryptionOracle.sol b/contracts/decryptionOracle/DecryptionOracle.sol
index cdca898..d34b203 100644
--- a/contracts/decryptionOracle/DecryptionOracle.sol
+++ b/contracts/decryptionOracle/DecryptionOracle.sol
@@ -19,8 +19,20 @@ contract DecryptionOracle is UUPSUpgradeable, Ownable2StepUpgradeable {
     /// @notice Patch version of the contract.
     uint256 private constant PATCH_VERSION = 0;
 
-    event DecryptionRequest(uint256 indexed requestID, uint256[] cts, address contractCaller, bytes4 callbackSelector);
+    /**
+     * @dev Event emitted during each decryption request. The off-chain gateway service is listening to it.
+     */
+    event DecryptionRequest(
+        uint256 indexed counter,
+        uint256 requestID,
+        uint256[] cts,
+        address contractCaller,
+        bytes4 callbackSelector
+    );
 
+    /**
+     * @dev Should revert when msg.sender is not authorized to upgrade the contract.
+     */
     function _authorizeUpgrade(address _newImplementation) internal virtual override onlyOwner {}
 
     /// @custom:storage-location erc7201:fhevm.storage.DecryptionOracle
@@ -51,22 +63,27 @@ contract DecryptionOracle is UUPSUpgradeable, Ownable2StepUpgradeable {
         _disableInitializers();
     }
 
-    function initialize(address _decryptionOracleOwner) external initializer {
-        __Ownable_init(_decryptionOracleOwner);
+    /**
+     * @notice              Initializes the contract.
+     * @param initialOwner  Initial owner address.
+     */
+    function initialize(address initialOwner) external initializer {
+        __Ownable_init(initialOwner);
     }
 
     /** @notice Requests the decryption of n ciphertexts `ctsHandles` with the result returned in a callback.
      * @notice During callback, msg.sender is called with [callbackSelector,requestID,decrypt(ctsHandles[0]),decrypt(ctsHandles[1]),...,decrypt(ctsHandles[n-1]),signatures]
+     * @param requestID is the request index generated by the dApp requesting the decryption.
      * @param ctsHandles is an array of uint256s handles.
      * @param callbackSelector the callback selector to be called on msg.sender later during fulfilment
      */
     function requestDecryption(
+        uint256 requestID,
         uint256[] calldata ctsHandles,
         bytes4 callbackSelector
-    ) external virtual returns (uint256 requestID) {
+    ) external virtual {
         DecryptionOracleStorage storage $ = _getDecryptionOracleStorage();
-        requestID = uint256(keccak256(abi.encodePacked(msg.sender, $.counter)));
-        emit DecryptionRequest(requestID, ctsHandles, msg.sender, callbackSelector);
+        emit DecryptionRequest($.counter, requestID, ctsHandles, msg.sender, callbackSelector);
         $.counter++;
     }
 
diff --git a/contracts/decryptionOracleLib/DecryptionOracleCaller.sol b/contracts/decryptionOracleLib/DecryptionOracleCaller.sol
index bb012ae..a2b537c 100644
--- a/contracts/decryptionOracleLib/DecryptionOracleCaller.sol
+++ b/contracts/decryptionOracleLib/DecryptionOracleCaller.sol
@@ -15,7 +15,7 @@ interface IKMSVerifier {
 }
 
 interface IDecryptionOracle {
-    function requestDecryption(uint256[] calldata ctsHandles, bytes4 callbackSelector) external returns (uint256);
+    function requestDecryption(uint256 requestID, uint256[] calldata ctsHandles, bytes4 callbackSelector) external;
 }
 
 struct DecryptionOracleConfigStruct {
@@ -28,6 +28,8 @@ abstract contract DecryptionOracleCaller {
     error InvalidKMSSignatures();
     error UnsupportedHandleType();
 
+    uint256 internal counterRequest;
+    mapping(uint256 => uint256[]) private requestedHandles;
     mapping(uint256 => ebool[]) private paramsEBool;
     mapping(uint256 => euint4[]) private paramsEUint4;
     mapping(uint256 => euint8[]) private paramsEUint8;
@@ -37,9 +39,6 @@ abstract contract DecryptionOracleCaller {
     mapping(uint256 => eaddress[]) private paramsEAddress;
     mapping(uint256 => address[]) private paramsAddress;
     mapping(uint256 => uint256[]) private paramsUint256;
-    mapping(uint256 => uint256[]) private requestedHandles;
-
-    constructor() {}
 
     function addParamsEBool(uint256 requestID, ebool _ebool) internal {
         paramsEBool[requestID].push(_ebool);
@@ -199,11 +198,13 @@ abstract contract DecryptionOracleCaller {
         uint256[] memory ctsHandles,
         bytes4 callbackSelector
     ) internal returns (uint256 requestID) {
+        requestID = counterRequest;
         FHEVMConfig.FHEVMConfigStruct storage $ = Impl.getFHEVMConfig();
         IACL($.ACLAddress).allowForDecryption(ctsHandles);
         DecryptionOracleConfigStruct storage $$ = getDecryptionOracleConfig();
-        requestID = IDecryptionOracle($$.DecryptionOracleAddress).requestDecryption(ctsHandles, callbackSelector);
+        IDecryptionOracle($$.DecryptionOracleAddress).requestDecryption(requestID, ctsHandles, callbackSelector);
         saveRequestedHandles(requestID, ctsHandles);
+        counterRequest++;
     }
 
     /// @dev this function should be called inside the callback function the dApp contract to verify the signatures
diff --git a/contracts/test/asyncDecrypt.ts b/contracts/test/asyncDecrypt.ts
index 8f3a460..9288f8c 100644
--- a/contracts/test/asyncDecrypt.ts
+++ b/contracts/test/asyncDecrypt.ts
@@ -40,7 +40,8 @@ if (networkName === 'hardhat') {
   relayer = new ethers.Wallet(privKeyRelayer!, ethers.provider);
 }
 
-const argEvents = '(uint256 indexed requestID, uint256[] cts, address contractCaller, bytes4 callbackSelector)';
+const argEvents =
+  '(uint256 indexed counter, uint256 requestID, uint256[] cts, address contractCaller, bytes4 callbackSelector)';
 const ifaceEventDecryption = new ethers.Interface(['event DecryptionRequest' + argEvents]);
 
 let decryptionOracle: DecryptionOracle;
@@ -55,10 +56,15 @@ export const initDecryptionOracle = async (): Promise<void> => {
   }
   // this function will emit logs for every request and fulfilment of a decryption
   decryptionOracle = await ethers.getContractAt('DecryptionOracle', parsedEnv.DECRYPTION_ORACLE_ADDRESS);
-  decryptionOracle.on('DecryptionRequest', async (requestID, cts, contractCaller, callbackSelector, eventData) => {
-    const blockNumber = eventData.log.blockNumber;
-    console.log(`${await currentTime()} - Requested decrypt on block ${blockNumber} (requestID ${requestID})`);
-  });
+  decryptionOracle.on(
+    'DecryptionRequest',
+    async (counter, requestID, cts, contractCaller, callbackSelector, eventData) => {
+      const blockNumber = eventData.log.blockNumber;
+      console.log(
+        `${await currentTime()} - Requested decrypt on block ${blockNumber} (counter ${counter} - requestID ${requestID})`,
+      );
+    },
+  );
 };
 
 export const awaitAllDecryptionResults = async (): Promise<void> => {
@@ -92,10 +98,10 @@ const fulfillAllPastRequestsIds = async (mocked: boolean) => {
   const pastRequests = await ethers.provider.getLogs(filterDecryption);
   for (const request of pastRequests) {
     const event = ifaceEventDecryption.parseLog(request);
-    const requestID = event.args[0];
-    const handles = event.args[1];
-    const contractCaller = event.args[2];
-    const callbackSelector = event.args[3];
+    const requestID = event.args[1];
+    const handles = event.args[2];
+    const contractCaller = event.args[3];
+    const callbackSelector = event.args[4];
     const typesList = handles.map((handle) => parseInt(handle.toString(16).slice(-4, -2), 16));
     // if request is not already fulfilled
     if (mocked && !toSkip.includes(requestID)) {