MD5 checksum

[cancer10]

Hi,

Please take a look into this link:

http://www.phpmyadmin.net/home_page/downloads.php


You can see the "MD5 checksum" value for each download link.

Question: What is the "MD5 checksum" ? Whats the need for it? and how is it calculated/generated?


Thanx

[Mr. E. Cryptic]

MD5 is a form of one-way encryption. It returns a 32 character hash of a given value.

With regards to checking file downloads, the hash will only be the same if the files checked (the one on the server + the version you downloaded) are the same. So if your download is corrupted/incomplete, the hash values will not match.

The download provider provides the initial hash, then you can use a ultility on your computer to hash the downloaded version and compare the values to ensure your download is complete (sorry, don't know the names of any programmes off the top of my head).

if you're trying to use md5 in PHP then it's as simple as md5() (http://ie.php.net/manual/en/function.md5.php)

[Stephen Philbin]

On Linux (and I would imagine any other Unix-based operating system), it's just md5sum <filename>

I tend to do md5sum <filename>;echo <provided hash> to make it quick and easy to do a visual comparison of the hashes.