_Added in 2.3_

*$hmac(text|&binvar|filename, [key], [hash], [N])*

Returns an HMAC (keyed-Hash Message Authentication Code) based on the supplied key.

_See also [[$hotp]], [[$totp]]._

*Parameters*

table(ktable).
|*Parameter*|*Description*|
| text<notextile>|</notextile>&binvar<notextile>|</notextile>filename | The text or &binvar or filename to calculate. |
| [key] | The key to hash with. (optional) |
| [hash] | Hash type: md5, sha1 (default), sha256, sha384, or sha512. (optional) |
| [N] | The type to calculate N = 0 for plain text (default), 1 for &binvar, 2 for filename. (optional) |

*Example*

<pre>
; calculate the sha1 hmac hash for the text 'Hello World' using the key 'test'.
//echo -ag The sha1 hmac for Hello World is $hmac(Hello World, test, sha1)
</pre>