hash_hmac_file()

hash_hmac_file() — Generate a keyed hash value using the HMAC method and the contents of a given file.

Built-in function of PHP 8.5. The manual lists it as available in PHP 5 >= 5.1.2, PHP 7, PHP 8, PECL hash >= 1.1. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

Signature

hash_hmac_file(string $algo, string $filename, string $key, bool $binary = false): string|false

Parameters

Parameter	Type	What it takes
$algo	string	Name of selected hashing algorithm (e.g. "sha256"). For a list of supported algorithms see hash_hmac_algos(). Note: Non-cryptographic hash functions are not allowed.
$filename	string	URL describing location of file to be hashed; Supports fopen wrappers.
$key	string	Shared secret key used for generating the HMAC variant of the message digest.
$binary	bool	When set to true, outputs raw binary data. false outputs lowercase hexits.

Return value

Returns a string containing the calculated message digest as lowercase hexits unless binary is set to true in which case the raw binary representation of the message digest is returned. Returns false if the file filename cannot be read.

Example

A runnable snippet:

/* Create a file to calculate hash of */ file_put_contents('example.txt', 'The quick brown fox jumped over the lazy dog.'); echo hash_hmac_file('sha256', 'example.txt', 'secret');

Output:

9c5c42422b03f0ee32949920649445e417b2c634050833c5165704b825c2a53b

Changelog

Version	Change
8.0.0	Now throws a ValueError exception if algo is unknown or is a non-cryptographic hash function; previously, false was returned and an E_WARNING message was emitted.
7.2.0	Usage of non-cryptographic hash functions (adler32, crc32, crc32b, fnv132, fnv1a32, fnv164, fnv1a64, joaat) was disabled.