# Parse ASN.1 hex string

Abstract Syntax Notation One (ASN.1) is a standard and notation that describes rules and structures for representing, encoding, transmitting, and decoding data in telecommunications and computer networking. This operation parses arbitrary ASN.1 data and presents the resulting tree. Parse ASN.1 hex string lives in the **Cryptography** category of the `fx` menu.

## Parameters

| Parameter                          | Type   | Required | Default | Description                                            |
| ---------------------------------- | ------ | -------- | ------- | ------------------------------------------------------ |
| Input                              | string | yes      | —       | Value to transform. Previous step output or a literal. |
| Starting index                     | number | no       | `0`     | Numeric value. Default `0`.                            |
| Truncate octet strings longer than | number | no       | `32`    | Numeric value. Default `32`.                           |

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

## Returned value

| Type     | Description                                          |
| -------- | ---------------------------------------------------- |
| `string` | Result of the Parse ASN.1 hex string transformation. |

## Example

<details>
<summary>Run Parse ASN.1 hex string</summary>

Abstract Syntax Notation One (ASN.1) is a standard and notation that describes rules and structures for representing, encoding, transmitting, and decoding data in telecommunications and computer networking. 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. Review **Starting index**, **Truncate octet strings longer than** and keep defaults unless your format requires otherwise.

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

</details>