> ## Documentation Index
> Fetch the complete documentation index at: https://cofhe-docs.fhenix.zone/llms.txt
> Use this file to discover all available pages before exploring further.

# Inputs

> Learn how to handle encrypted user inputs in confidential smart contracts

## Overview

One of the key aspects of writing confidential smart contracts is receiving encrypted inputs from users:

```solidity theme={null}
function transfer(
    address to,
    InEuint32 memory inAmount // <------ encrypted input here
) public virtual returns (euint32 transferred) {
    euint32 amount = FHE.asEuint32(inAmount);
}
```

<Note>
  Notice in the example above the distinction between **`InEuint32`** and **`euint32`**.
</Note>

## Input Types Conversion

The **input types** `InEuintxx` (and `InEbool`, `InEaddress`) are special encrypted types that represent **user input**. Input types contain additional information required to authenticate and validate ciphertexts. For more on that, read about the [ZK-Verifier](/deep-dive/cofhe-components/zk-verifier).

Before you can use an encrypted input, you need to convert it to a regular **encrypted type**:

```solidity theme={null}
euint32 amount = FHE.asEuint32(inAmount);
```

<Tip>
  Avoid storing encrypted input types in contract state. These types carry extra metadata, which increases gas costs and may cause unexpected behavior. Always convert them using `FHE.asE...()`.
</Tip>

Now that `amount` is of type `euint32`, you can store or manipulate it:

```solidity theme={null}
toBalance = FHE.sub(toBalance, amount);
```

<Tip>
  Read more about the available FHE types and operations in the [FHE Encrypted Operations](/fhe-library/core-concepts/encrypted-operations) guide.
</Tip>

## Full Example

Here's a complete example showing how to handle encrypted inputs in a transfer function:

```solidity theme={null}
function transfer(
    address to,
    InEuint32 memory inAmount
) public virtual returns (euint32 transferred) {
    euint32 amount = FHE.asEuint32(inAmount);

    toBalance = _balances[to];
    fromBalance = _balances[msg.sender];

    _updateBalance(to, FHE.add(toBalance, amount));
    _updateBalance(from, FHE.sub(fromBalance, amount));
}
```

<Note>
  For the example above to work correctly, you will also need to manage access to the newly created ciphertexts in the `_updateBalance()` function. Learn more about access control in the [ACL Mechanism](/fhe-library/core-concepts/access-control) guide.
</Note>

## Additional Examples

### Voting in a Poll

```solidity theme={null}
function castEncryptedVote(address poll, InEbool calldata encryptedVote) public {
    _submitVote(poll, FHE.asEbool(encryptedVote));
}
```

### Setting Encrypted User Preferences

```solidity theme={null}
function updateUserSetting(address user, InEuint8 calldata encryptedSetting) public {
    _applyUserSetting(user, FHE.asEuint8(encryptedSetting));
}
```