Message digest technology lets you make sure the files you download are correct down to the last bit. Data corruption, transmission errors, browser issues and malware infections can damage files. The MD5 algorithm of 128 bits calculates a hash number based on the exact bit settings in a file. The organization offering a file for download provides a hash number, which is compared to the file in question.
Windows machines do not support this functionality, so additional software must be installed. The File Integrity Checker is an official Microsoft tool, but, ironically, not supported and may not work with all installations. Fortunately, there is a real port of the md5sum utility available to system administrators * NIX for Microsoft Windows
Running md5
Point your browser to http://www.fourmilab.ch/md5/ , which is the official page of the Command Line Message Compendium utility. Download the md5.zip file. Open File Explorer by holding down the Windows key and pressing E. Double click on the md5 icon and select »Extract to folder…» and name the folder md5. Double click on the new folder.
Open a command window by holding down the Windows key, press R then type cmd. Hit enter and then navigate to where you created the new folder by typing:
cd «My documents» Download 5 (tixag 1)
Depending on your browser, you can use a different download path. Once there, type md5 and then the path of the file you want to inspect. If you want to check a file called updates.zip that was in the Program Files directory, can, for example, issue this command:
md5 “C: N-Program FilesN-update.zip”
The program will return a series of characters, which you can check with the checksum from the original download page of the file. Remember that you can drag and drop the files on the command line to complete the path for you.
