PHP - Hash hmac() Function

Definition and Usage

The hash_hmac() function is used to generate keyed hash value using HMAC method.

HMAC stands for keyed-hash message authentication code or hash-based message authentication code. It makes use of cryptographic hash function like md5, sha-256 and a secret key to return the message digest hash of the given data.

Syntax

hash_hmac ( string $algo , string $data , string $key [, bool $raw_output = FALSE ] ) : string

Parameters

Sr.No	Parameter & Description
1	algo Name of the hashing algorithm. There is a big list of algorithm available with hash, some important ones are md5, sha256, etc. To get the full list of algorithms supported check for hash_hmac_algos()
2	data The data you want to hash.
3	key Secret key to generate HMAC vaiant of the message digest.
4	raw_output By default, the value is false and hence it returns lowercase hexits values. If the value is true, it will return raw binary data.

Return Values

The hash_hmac() function returns a string containing calculated message digest that will be in the form of lowercase hexits if raw_output is false otherwise it will return raw binary data.

PHP Version

This function will work from PHP Version greater than 5.1.2.

Example 1

Using hash_hmac() −

Live Demo

<?php
   echo hash_hmac('md5', 'Welcome to Tutorialspoint', 'any_secretkey');
?>

Output

This will produce the following result −

3e89ca31da24cb046c9d11706be688c1

Example 2

Using hash_hmac() with ripemd128 algorithm −

Live Demo

<?php
   echo hash_hmac('ripemd128', 'Welcome to Tutorialspoint', 'any_secretkey');
?>

Output

This will produce the following result −

c9b5c68b72808f31b4524fbd46bf87d0

Example 3

To generate hash_hmac with raw_output as true −

<?php
   echo hash_hmac('ripemd128', 'Welcome to Tutorialspoint', 'any_secretkey', true);
?>

Output

This will produce the following result −

ɵƋr��1�RO�F���

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