A file hash (or checksum) is a unique digital fingerprint generated from a file's contents. Even a tiny change in the file—a single bit—will produce a completely different hash. By comparing the hash of your downloaded file to the one provided by the source, you can verify its integrity.

There are two main reasons:

• Security: It ensures the file hasn't been tampered with by a third party and infected with malware.
• Data Integrity: It confirms that the file was not corrupted during the download process, which can happen with large files or unstable internet connections.

Absolutely not. This tool is 100% private and runs entirely in your browser. The file you select is read and processed locally on your computer. It is never uploaded or sent anywhere. You can verify this by disconnecting from the internet after the page loads—the tool will still work perfectly.

1. Find the official hash: Go to the website where you downloaded the file. The developer (e.g., Microsoft) usually provides the official checksums (often SHA-256) on the download page. Copy it.
2. Choose your file: Drag and drop your downloaded file (e.g., a `.iso` or `.exe`) into the box above, or click to select it.
3. Select the algorithm: Make sure the algorithm you select (e.g., SHA-256) matches the one provided by the developer.
4. Paste the official hash: Paste the hash you copied into the "Expected Hash" field. The tool will automatically start calculating and comparing.
5. Check the result: The tool will show you a green "MATCH" if the fingerprints are identical, or a red "NO MATCH" if there is a problem.

Do not open or run the file. A mismatch means the file is either corrupted or has been tampered with. Delete the file immediately and download it again, preferably from a different source if possible. If it fails a second time, contact the software provider.