How to verify the checksum of a downloaded file

Issue: You would like to verify the integrity of your downloaded files. Extract the downloaded zip and launch the WinMD5. Click on the Browse button, navigate to the file that you want to check and select it. Just as you select the file, the tool will show you its MD5 checksum.

Copy and paste the original MD5 value provided by the developer or the download page. Click on Verify button. If you were to hash a character long file, the resulting MD5 checksum is still 32 characters. Even if the source file was only 10 characters long, the MD5 checksum would still be 32 random characters.

But if even one thing is different, like an extra space in the file, the checksum will be completely different. The version is identified as either a number like 1, 2, 3, or by the number of times SHA is run in succession, such as , , or The checksum you use should specify which version of SHA to use. For the purposes of file verification, both methods are equally valid. Though the algorithm is different, both will return a random string with a set length, although MD5 hashes are shorter than any of the SHA hashes.

Those steps are beyond the scope of this tutorial. Checking the hash on downloaded files provides two different assurances that are both worthwhile. Both of these cases are important since, if either were to happen, the download you have could be harmful to your machine or may not work at all.

Most Linux distributions have command line tools for each hashing algorithm. So to hash with MD5, the program name is md5sum. To hash with SHA , the command is shasum. Downloading a file used to be a risk. It can still be risky and you might still end up with malware on your system but there are more robust protections in place now. No two people can have the same fingerprints. Similarly, no two files can ever have the same checksum values. If a file has been modified, its checksum value will be different from what it was before the modification was made.

Additional information How to protect yourself while on the Internet. See our checksum page for further information and related links. Microsoft Windows help and support. Was this page useful? Small changes in the file produce very different checksum.

Checksums often accompany software downloaded from the web so that users can ensure the file or files were not modified in transit. If the checksum from the software vendor matches the checksum of the downloaded installation files on your computer, then no errors or modifications were made. However, if the resulting hash does not match the hash from the website, then the downloaded file might have been corrupted or compromised by hackers. Of course, not all websites offer you the chance to cross-reference a file hash to ensure file integrity.

Unfortunately, because many people do not take the time to vet their downloads many major websites don't offer file hashing comparisons. Navigate to the desktop location where the file is located. If you use the default settings, this command should work:.