PHP md5_file()
Function
Example
Calculate the MD5 hash of the text file "test.txt":
The above code will output:
Definition and Usage
The md5_file()
function calculates the MD5 hash of a file.
The md5_file()
function uses the RSA Data Security, including the MD5 Message-Digest Algorithm.
Explanation from RFC 1321 - MD5 Message-Digest Algorithm: The MD5 Message-Digest Algorithm takes an input and converts it into a 128-bit fingerprint or "message digest" that represents the input. The algorithm is primarily designed for digital signature applications; in these applications, larger files are securely compressed before being encrypted (the encryption process is done by setting a private key under a public key in a cryptographic system, such as RSA).
To calculate the MD5 hash of a string, use the md5() function.
Syntax
Parameter | Description |
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file | Required. Specifies the file to calculate. |
raw | Optional. A boolean value that specifies hexadecimal or binary output format: TRUE - Raw 16-character binary format<br> FALSE - Default. 32-character hexadecimal number |
Technical Details
Return Value: | Returns the calculated MD5 hash on success, or FALSE on failure. |
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PHP Version: | 4.2.0+ |
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Changelog: | In PHP 5.0, the raw parameter became optional. <br> <br>Since PHP 5.1, md5_file() can be used with wrappers. For example: md5_file("http://w3cschool.cc/..") |
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More Examples
Example 1
Store the MD5 hash of "test.txt" in a file:
Check if "test.txt" has been altered (i.e., if the MD5 hash has changed):
The above code will output: