# hash_hmac

(PHP 5 >= 5.1.2, PECL hash:1.1-1.5)

hash_hmac — Generate a keyed hash value using the HMAC method

### Description

string hash_hmac ( string `$algo` , string `$data` , string `$key` [, bool `$raw_output` ] )

### Parameters

`algo`

  Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..)

`data`

  Message to be hashed.

`key`

  Shared secret key used for generating the HMAC variant of the message digest.

`raw_output`

  When set to `TRUE`, outputs raw binary data. Default value (`FALSE`) outputs lowercase hexits.

### Return Values

Returns a string containing the calculated message digest as lowercase hexits unless `raw_output` is set to true in which case the raw binary representation of the message digest is returned.

### Examples

Example#1 hash_hmac() example

`<?php
echo hash_hmac('ripemd160', 'The quick brown fox jumped over the lazy dog.', 'secret');
?>`

The above example will output:

    b8e7ae12510bdfb1812e463a7f086122cf37e4f7

### See Also

- hash()
- hash_init()
- hash_hmac_file()