WeberDev.com -> PHP Manual -> Calculates the md5 hash of a given file

string md5_file ( string $filename [, bool $raw_output ] )

Calculates the MD5 hash of the file specified by the filename parameter using the » RSA Data Security, Inc. MD5 Message-Digest Algorithm, and returns that hash. The hash is a 32-character hexadecimal number.

filename: The filename
raw_output: When TRUE, returns the digest in raw binary format with a length of 16. Defaults to FALSE.

Returns a string on success, FALSE otherwise.

Version	Description
5.0.0	Added the `raw_output` parameter
5.1.0	Changed the function to use the streams API. It means that you can use it with wrappers, like md5_file('http://example.com/..')

Example #1 Usage example of md5_file()

 <?php
$file = 'php-5.3.0alpha2-Win32-VC9-x64.zip';

echo 'MD5 file hash of ' . $file . ': ' . md5_file($file);
?>

md5_file