A few scenarios spring to mind where it can be essential to make sure that files have not been modified. Think of data backups for example. Nothing is worse than having to realize that the dire needed backup is corrupt and cannot be used. Or files on a web server. A good way to make sure that no one tampered with the files is to verify them regularly.
But file integrity can be important on the local PC as well. A program like Exact File can tell you exactly if someone modified your Word or Excel document, or played your game just a little bit further.
Exact File is a free file integrity tool for the Windows operating system. It can process single files or batch process complete folders. The software supports all important hash methods including MD5, SHA512, CRC32 and about a dozen more.
Options to create checksums for single or multiple files, as well as to verify the integrity of already checked files are offered in the program's interface.
A single-file check works by dragging and dropping a file into the interface, or selecting it in the file browser. ExactFile will compute all supported hashes and display a report in the end listing them all.
The generated information can be copied to the clipboard. More interesting is the ability to create a digest. A digest contains hash values of all files found in a selected folder and its subfolders.
It is again possible to drag and drop a folder into the program window, or to use the file browser to pick a folder from the system. Available options are to include subfolders, full paths in the output and to out the checksums to a file.
All supported hash methods are available, but only one can be selected for the process.
ExactFile will process all files in the selected folder structure and display a similar results window in the end.
The calculations are speedy and use all available cpu cores by default. The results are stored in the selected file and displayed to the user directly. It is here again possible to copy them to the clipboard.
The test digest menu is available to test a previously generated folder hash. All it takes is to select the digest file, click verbose report and then go to compare the previously generated hash values of the files with the current ones.
One interesting application for this would be to generate the hashes before sending the files to another user. The receiving user could then test the validity of the files by running the previously generated checksum file against the received files.
An option to create a test file applet is available to make this easier. Instead of having to use the file integrity software to check the files, it is possible to generate and use a standalone executable generated by the program to do the same. Ideal for putting it on burned CDs or DVDs, or sending it along with the files for the recipient to check.
Exact File is a sophisticated file verification tool for the Windows operating system. Especially the option to test and verify the integrity of all files in a folder is welcome, coupled with the option to create a standalone executable to verify the integrity at all times.
What the developer of Exact File says:
- A file integrity verification tool:
Use it to make sure files copied to CD-ROM are bit-perfect copies,
Use it to make sure backups copied from one drive to another are just right,
Use it to make sure files haven’t been changed or damaged over time.
- Multi-threaded, so your extra CPU cores get used when scanning multiple files and work gets done faster.
- Happy with Unicode file names, so it doesn’t fail when you’re using it on files named in Japanese, Hebrew, Chinese, or any other language.
- Supports multiple checksum routines (hashes), like MD5, SHA1, CRC32, RIPEMD and others.
- Supports recursive directory scanning.
- Supports Very Big Files — If it’s on your hard drive, ExactFile can handle it.
- Does everything popular file summer utilities do, like fsum, md5sum, sha1sum, sfv, etc, but better!
- Compatible with popular file checksum digest formats.
- For Windows 2000, XP, and Vista.
- GUI. Easy to use to get checksums for individual files, create checksum digests, and test checksum digests. Does not require the console version or any external DLLs.
Interested users can download Exactfile from the developer homepage. The program is compatible with most 32-bit and 64-bit editions of the Windows operating system.
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Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.