The software program does not act automatically. The user has to select files or folders that he wants to calculate hash values for. Once they are stored in the database it is possible to check the files at anytime to see if the file has been changed in the meantime.

A set of 21 different hash algorithms including popular algorithms like MD5, SHA-512 or CRC-32 is available and at the user’s disposal. Results can be saved or loaded so that they are available whenever they are needed.

Other interesting options include Windows Shell integration, a command line version, drag and drop support, Unicode support or search and grep using regular expressions. All in all a very sophisticated tool to check the file integrity of selected files.

Let me first explain why it could be important to check the hash algorithm of downloaded files. Many software developers and download portals add hash information to their downloads. Those information clearly identify a file and the user can compare the hash of a downloaded file with the hash on a website to make sure that he got that file and that no one tampered with it in the meantime.

It obviously makes only sense if the hash information are published on the website that contains the download. MD5 Hasher makes use of the Firefox Download Manager which means that the downloads have to appear in there because it is currently the only way to check the hash of the file.

MD5 Hasher can check a variety of hash algorithms including MD5, SHA1 and SHA512. Just make sure you pick the right one when comparing the checksums. A right-click on a downloaded file and the selection of Check Digest opens the MD5 Hasher window that provides access to the checksum comparison.

It’s not as comfortable as it could be because of several reasons. A direct link to the functions of the add-on would be nice. It would also be great if the hashes would be displayed automatically and if previous downloads could be processed as well.