PHP | hash_equals() Function

The hash_equals function() is an inbuilt function in PHP which is used to compares two strings using the same time whether they are equal or not.
Syntax:

hash_equals( $known_str, $usr_str )

Parameters: This function accept two parameters as mention above and describe below. 

• $known_str: This parameter is used to specify the known length string.
• $usr_str: This parameter is used to specify the user-supplied string.

Return Value: This function returns True if both strings are equal, False otherwise.
Below programs illustrate the hash_equals() function in PHP:
Program 1:

php

<?php

// PHP program to illustrate
// hash_equals function
$known_str = crypt('GFG', 'Hello-GFG');
$usr_str   = crypt('GFG', 'Hello-GFG');

// Compare both strings
$res = hash_equals($known_str, $usr_str);

// Display result
var_dump($res);
?>

Output:

bool(true)

Program 2:

php

<?php

// PHP program to illustrate
// hash_equals function
$known_str = crypt('GFG', 'Hello-GFG');
$usr_str   = crypt('GeeksforGeeks', 'Hello-GFG');

// Compare both strings
$res = hash_equals($known_str, $usr_str);

// Display result
var_dump($res);
?>

Output:

bool(false)

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