# Adler-32 Checksum

Adler-32 is a checksum algorithm which was invented by Mark Adler in 1995, and is a modification of the Fletcher checksum. Compared to a cyclic redundancy check of the same length, it trades reliability for speed (preferring the latter). Adler-32 is more reliable than Fletcher-16, and slightly less reliable than Fletcher-32. Adler-32 Checksum lives in the **Hashing** category of the `fx` menu.

## Parameter

| Parameter | Type   | Required | Default | Description                                            |
| --------- | ------ | -------- | ------- | ------------------------------------------------------ |
| Input     | string | yes      | —       | Value to transform. Previous step output or a literal. |

`Input` is the primary value (previous step output or a literal).

## Returned value

| Type     | Description                                     |
| -------- | ----------------------------------------------- |
| `string` | Result of the Adler-32 Checksum transformation. |

## Limitations

- This operation treats Input as raw bytes (binary-capable). Non-text payloads may display differently after decoding.
- Wrong key, algorithm options, or malformed input typically raises an evaluation error — fix Input or options before re-running.

## Example

<details>
<summary>Run Adler-32 Checksum</summary>

Adler-32 is a checksum algorithm which was invented by Mark Adler in 1995, and is a modification of the Fletcher checksum. Adjust optional parameters when the defaults do not match your payload.

1. Set **Input** to the value to transform (previous step output or a literal).

2. Confirm **Output value** shows the transformed result.

</details>