User Random Number generation

Hi
Can I generate my userRandomNumber on-chain that I need to pass to Entropy provider? Are there any security consideration regarding that?

  function requestRandomNumber(bytes32 userRandomNumber) external payable {
    // Get the default provider and the fee for the request
    address entropyProvider = entropy.getDefaultProvider();
    uint256 fee = entropy.getFee(entropyProvider);
 
    // Request the random number with the callback
    uint64 sequenceNumber = entropy.requestWithCallback{ value: fee }(
      entropyProvider,
      userRandomNumber
    );
    // Store the sequence number to identify the callback request
  }```