> For the complete documentation index, see [llms.txt](https://docs.wem.io/platform/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wem.io/platform/wemreference/functions/security/hmacsha256.md).

# HmacSha256

{% hint style="info" %}
The **`HmacSha256()`** function calculates a [MAC (message authentication code)](https://en.wikipedia.org/wiki/Hash-based_message_authentication_code) on provided message using the SHA256 hash function and a key/secret, and returns the calculated MAC as a hexadecimal text string.

This function is NOT SQL compatible. For more information about SQL compatibility, see our [documentation](/platform/wemreference/sql-compatibility.md).

*Hashed values cannot be decoded, usually you check an incoming value against a known value that you hash yourself and check if both values are identical, to verify correctness without knowing the actual value.*
{% endhint %}

{% hint style="success" %}
Returns a hexadecimal text representation of a message, which is hashed using the Sha265 function and the key/secret for additional calculation/hashing. \
Returns <mark style="color:red;">**`Unknown`**</mark> if one of the parameter values is unknown or outside the common valid boundaries.
{% endhint %}

### Syntax

<details>

<summary><code>HmacSha256(</code><mark style="color:blue;"><code>key</code></mark><code>, </code><mark style="color:blue;"><code>message</code></mark><code>)</code></summary>

`HmacSha256("", "")`\
*=> "b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad"*

`HmacSha256("key", "The quick brown fox jumps over the lazy dog")`\
*=> "f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8"*

</details>

<details>

<summary><code>HmacSha256(</code><mark style="color:blue;"><code>key</code></mark><code>, </code><mark style="color:blue;"><code>message</code></mark><code>, </code><mark style="color:blue;"><code>returnasbase64</code></mark><code>)</code></summary>

`HmacSha256("Secret Key", "testing the hmacsha265 converter", true)`\
*=> "hhG+nxnGLS4pT5DVoMyP8VoNrpbnkNaK8e7g5COSb+A="*

`HmacSha256("Secret Key", "testing the hmacsha265 converter", false)`\
*=> "8611be9f19c62d2e294f90d5a0cc8ff15a0dae96e790d68af1eee0e423926fe0"*

</details>

### Parameters

<table><thead><tr><th width="203.70825474075613">Name</th><th width="150">Type</th><th width="150" align="center">Required</th><th width="248.15953250810662">Description</th><th data-hidden>Required?</th></tr></thead><tbody><tr><td><mark style="color:blue;"><code>key</code></mark></td><td>text</td><td align="center"><span data-gb-custom-inline data-tag="emoji" data-code="2611">☑️</span></td><td>a text with the secret key for HmacSha256 encryption</td><td>yes</td></tr><tr><td><mark style="color:blue;"><code>message</code></mark></td><td>text</td><td align="center"><span data-gb-custom-inline data-tag="emoji" data-code="2611">☑️</span></td><td>the message or content </td><td>yes</td></tr><tr><td><mark style="color:blue;"><code>returnbase64</code></mark></td><td>yes/no</td><td align="center"></td><td>return result as base64 (if true)</td><td>yes</td></tr></tbody></table>


---

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