> ## 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.

# Trivial Encryption

> Understanding the difference between trivially encrypted numbers and encrypted inputs

## Overview

In FHE-enabled smart contracts, you often need to perform operations between encrypted values and regular plaintext values. **Trivial encryption** is the operation of converting a plaintext value into an encrypted format that can interact with other encrypted data.

This conversion is done using the `FHE.asEuint` family of functions, which take standard Solidity types and transform them into their encrypted counterparts.

```solidity theme={null}
uint16 number = 2;
euint16 encrypted_number = FHE.asEuint16(number);
```

## Privacy Considerations

**Trivially encrypted values are not confidential** - they are merely a tool to enable interaction between encrypted and non-encrypted types. The original plaintext value remains visible to anyone observing the blockchain, just in a different format.

This is a crucial concept to understand when developing confidential contracts. Any value that is trivially encrypted (e.g. `encrypted_number`) should be treated as public information, even though it uses the same data type as truly encrypted values.

<Warning>
  `euints` are only confidential when they are formed from encrypted `inEuint` inputs, which are encrypted off-chain. Learn more in the [Data Evaluation](/fhe-library/core-concepts/data-evaluation) guide.
</Warning>

When two trivially-encrypted numbers are combined in an FHE operation, the result is still not confidential, because an observer can keep track of the calculations.

## Example

```solidity theme={null}
function doSomeCalculations(InEuint16 calldata input) {
    // public
    euint16 number2 = FHE.asEuint16(2);
    euint16 number3 = FHE.asEuint16(3);
    euint16 number5 = FHE.add(number2, number3);

    // confidential
    euint16 encInput = FHE.asEuint16(input);
    euint16 encMul = FHE.mul(encInput, number5);

    // public
    euint16 eFalse = FHE.asEbool(false);

    // Observer knows that result is encInput, but not what the value is
    euint16 result = FHE.select(eFalse, encMul, encInput);
}
```