How do I use an MD5 checksum?

If you followed the links on my last post, one of them would have taken you to the Torpark web browser download page. When downloading Torpark, you are given an md5 checksum number. I am sure that a lot of people do not use checksums, and really do not understand their importance. Checksums are used to verify that a file that you downloaded is actually the original.

Chaos MD5 CheckerTo put it in basic terms, a checksum number is a unique number generated from a certain algorithm that is run on a file. If the file has any differences at all from another file, the checksum will be different.

These checksums can be important. Let’s say that I broke into some download mirror, and replaced one of their popular files with one of mine. Maybe the software ran the same, but I added a basic instruction to log keystrokes and send them to a server of my choosing. Since you just innocently downloaded the file (and from a trusted source) you have no idea of this added functionality found in the program.

If you had checked your download against the checksum located on the website, you would have noticed that a different number resulted from the checksum. You would have known right off the bat that the file was corrupt, and that you should try to download it again.

In order to use an md5 checksum, all you need is a program to check the md5 that results from a given file. I would recommend ChaosMD5 2.0 by Elgorithms. There are many other great MD5 checkers, this is just the one that I use.

To use it, click the folder icon on the right to browse to a file that you wish to check. This should be the original downloaded file. After selecting the file, click the “Generate MD5” button. A few seconds later, your MD5 should be generated. Compare it with your original (from the download website). If they are the same, your file is OK. If you have different numbers, DO NOT use the file. Get rid of it and try again.

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