PHP | hash_hmac() Function

Hello dear readers! welcome back to another edition of our tutorial on PHP. In this tutorial guide, we are going to be discussing about the PHP hash_hmac() Function.

The built-in hash_hmac() function is used for generating keyed hash value using HMAC method.

HMAC is an acronym which simply 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

Following below is the syntax to use this function -

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

READ: PHP | hash_hkdf() Function

Parameter Details

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 Value

This built-in PHP function returns a strings of 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 built-in function works from PHP version greater than 5.1.2.

Example1

The following below is an example which demonstrates the usage of PHP hash_hmac() function -

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

Output

When the above code is executed, it will produce the following result -

82b39d2ebabc8828e56c660f6fe7c20a

Example2

Using the built-in hash_hmac() function with ripemd128 algorithm -

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

Output

When the above code is executed, it will produce the following result -

286baab9161f7eb45c9a4435ff7d0a35

Example3

Following example demonstrates how to generate hash_hmac with raw_output set as TRUE -

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

Output

When the above code is executed, it will produce the following result -

ɵƋr��1�RO�F���

READ: PHP | hash_equals() Function

Alright guys! This is where we are rounding up for this tutorial post. In our next tutorial, we will discuss about the PHP hash_hmac_algos() Function.

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