php man page for hash_hmac

HASH_HMAC(3)								 1							      HASH_HMAC(3)

hash_hmac - Generate a keyed hash value using the HMAC method

SYNOPSIS
       string hash_hmac (string  $algo, string	$data, string  $key, [bool  $raw_output = false])

DESCRIPTION
PARAMETERS
	      o $algo
		-  Name  of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..) See hash_algos(3) for a list of supported algo-
		rithms.

	      o $data
		- Message to be hashed.

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

	      o $raw_output
		- When set to TRUE, outputs raw binary data.  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. Returns FALSE when $algo is unknown.

EXAMPLES
       Example #1

	      hash_hmac(3) 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(3), hash_algos(3), hash_init(3), hash_hmac_file(3).

PHP Documentation Group 													      HASH_HMAC(3)