# crypto.hmac_sha512

## Function

Generate an HMAC-SHA512 signature of the current text using the key.

## Syntax

```bt
crypto(text).hmac_sha512(key)
```

## Parameters

| Parameters | Type | Required | Default value | Description |
| ------ | ------ | ------ | ------ | ------ |
| key | String | Yes | None | HMAC key. |

## Return value

| Type | Description |
| ------ | ------ |
| String | HMAC-SHA512 lowercase hexadecimal signature. |

## Code Example

```bt
result = crypto('payload').hmac_sha512('secret')

// Output: 291ddaaa23cafa3aaae1c9755391f4bef35bbdbcb92739a5618a5c896f6520d2b0d28d2d2987dac97479e31214a51d96cfceafa28e46a4f961b63c46352a189e
print result
```

## Notes

- Both text and keys participate in the calculation as UTF-8 bytes.