For this section, we refer you to the [tips-to-remain-anonymous.md](../general/guides/opsec.md "mention") tutorial as a first step. All points mentioned in this tutorial still apply to Tornado Cash Nova.
Gas fees payments are necessary for transactions. For shielded transfers & withdrawals, two payment methods are available to provide ETH for gas fee. You can either **connect your wallet or use a relayer**.
Going through your wallet for this gas fee can compromise the anonymity of the transaction if used ETH are linkable to your identity. Therefore, **it is recommended to use a Relayer to preserve privacy**
Choosing one of the four predefined amounts is strongly recommended as it will allow your withdrawal to blend with the crowd and remain anonymous.
You still have the freedom to `Set custom` to withdraw a customized amount of you choice. However, depending on the chosen amount, a connection might be deduced between your initial fund transaction and your withdrawal if:
* the initially funded amount & the withdrawn amount are exactly the same,
* the funded & withdrawn amounts can easily be linked through a sum.
For instance, a deposit of 0.42 ETH can be linked to a withdrawal of exactly 0.42 ETH or two times 0.21 ETH, which might compromise anonymity. However, with a withdrawal of 0.391 ETH, privacy is better preserved as there is no obvious link between the 0.42 & 0.391 amounts.
The custom option should only be chosen with full knowledge of these facts and in complete confidence in your actions.
