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

# isValidSHA256

> Validates if a string matches the SHA-256 hash pattern (64 hexadecimal characters).

## Input

* **`input`**: The original input text or data
* **`output`**: The string to validate
* **`expectedOutput`**: The expected output to compare against.

<Note>
  - Any of the input variables (`input`, `output`, `expectedOutput`) can be marked as optional.
  - The returned value from the `validate` function can be a boolean, string, or a number.
</Note>

## Output

* **`Result`**: (`true` or `false` , string or a number)

## Interpretation

> *assuming response format is boolean*

* **true**: The string matches the SHA-256 pattern
* **false**: The string does not match the SHA-256 pattern

<Note>This evaluator requires a function named <code>validate</code>.</Note>

## Example

```python theme={null}
import re

def validate(input, output, expectedOutput):
    pattern = r'^[a-fA-F0-9]{64}$'
    return re.match(pattern, str(output)) is not None
```