PHP | hash_hmac_file() Function

The hash_hmac_file() function is an inbuilt function in PHP that is used to generate a keyed hash value using the contents of a given file. 

Syntax:

string hash_hmac_file( $algo, $file, $key, $raw_opt )

Parameters: This function accepts four parameters as mentioned above and described below.

• $algo: It is the required parameter that specifies the selected hashing algorithm.
• $file: This parameter is used to specify the file URL to be hashed.
• $key: This parameter is used to hold the shared secret key used for generating the HMAC.
• $raw_opt: If the parameter is set to true then output will be raw binary data and if the parameter is set to False then output will be lowercase exits.

Return Value: This function returns a string containing the calculated message digest as lowercase exits. The below programs use the file gfg.txt and the contents of the file are:

GeeksforGeeks A Computer Science Portal for Geeks

The below programs illustrate the hash_hmac_file() function in PHP.

Program 1: 

<?php

// PHP program to illustrate
//  hash_hmac_file function


// Create a file to calculate hash of
file_put_contents('gfg.txt', 'Geeks');

// Display result
echo hash_hmac_file('sha1', 'gfg.txt',
            'password', false);
?>

Output:

a5365a345a41ac0780bf63e4d33576560b86163c

Program 2: 

<?php

// PHP program to illustrate
//  hash_hmac_file function

// Create a file to calculate hash of
file_put_contents('gfg.txt', 'Geeks');

// Display result
echo hash_hmac_file('sha256', 'gfg.txt', 'password') . "</br>";


// Create a file to calculate hash of
file_put_contents('gfg.txt', 'Content');

// Display result
echo hash_hmac_file('md5', 'gfg.txt', 'password', false);
?>

Output:

a73af6923445a30fbacd646622b254069f90c2502e63b1025918aa93f2ddca9d
a7b2b24ac2334070c42a852fb5ef0c92 

Reference: http://php.net/manual/en/function.hash-file.php