(PHP 5 >= 5.1.2, PECL hash >= 1.1)
hash_file — Generate a hash value using the contents of a given file
Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..)
URL describing location of file to be hashed; Supports fopen wrappers.
When set to TRUE, outputs raw binary data. FALSE outputs lowercase hexits.
Returns a string containing the calculated message digest as lowercase hexits unless raw_output is set to true in which case the raw binary representation of the message digest is returned.
Example #1 Using hash_file() 以上例程会输出：
<?php
/* Create a file to calculate hash of */
file_put_contents('example.txt', 'The quick brown fox jumped over the lazy dog.');
echo hash_file('md5', 'example.txt');
?>
5c6ffbdd40d9556b73a21e63c3e0e904