PHP md5_file() Function
 Complete PHP String Reference
Definition and Usage
The md5_file() function calculates the MD5 hash of a file.
The md5_file() function uses the RSA Data Security, Inc. MD5 Message-Digest
Algorithm.
From RFC 1321 -
The MD5 Message-Digest Algorithm: "The MD5 message-digest algorithm takes as
input a message of arbitrary length and produces as output a 128-bit
"fingerprint" or "message digest" of the input. The MD5 algorithm is intended for digital signature applications, where
a large file must be "compressed" in a secure manner before being encrypted with
a private (secret) key under a public-key cryptosystem such as RSA."
This function returns the calculated MD5 hash on success, or FALSE on failure.
Syntax
| Parameter |
Description |
| file |
Required. The file to be calculated |
| raw |
Optional. Specifies hex or binary output
format:
- TRUE - Raw 16 character binary format
- FALSE - Default. 32 character hex number
Note: This parameter was added in PHP 5.0 |
Example 1
<?php
$filename = "test.txt";
$md5file = md5_file($filename);
echo $md5file;
?>
|
The output of the code above will be:
5d41402abc4b2a76b9719d911017c592
|
Example 2
Store the MD5 hash of "test.txt" in a file:
<?php
$md5file = md5_file("test.txt");
file_put_contents("md5file.txt",$md5file);
?>
|
In this example we will test if "test.txt" has been changed (that is if the
MD5 hash has been changed):
<?php
$md5file = file_get_contents("md5file.txt");
if (md5_file("test.txt") == $md5file)
{
echo "The file is ok.";
}
else
{
echo "The file has been changed.";
}
?>
|
The output of the code above could be:
Complete PHP String Reference
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