Question 1

What is a file hash?

Accepted Answer

A file hash (or checksum) is a fixed-length string computed from a file's contents using a cryptographic algorithm. If even one bit of the file changes, the hash changes completely. Hashes are used to verify file integrity: if the hash of your downloaded file matches the published hash, the file has not been modified or corrupted.

Question 2

Which hash algorithm should I use?

Accepted Answer

SHA-256 is the current standard for file integrity verification and forensic evidence. MD5 and SHA-1 are considered cryptographically broken and should only be used for legacy compatibility. SHA-512 provides additional security but SHA-256 is sufficient for most purposes.

Question 3

Is my file uploaded to your server?

Accepted Answer

No. All hash calculations happen entirely in your web browser using the Web Crypto API. Your file never leaves your computer. The tool reads the file locally, computes hashes in memory, and displays the results. Zero data is transmitted to any server.

Question 4

How large a file can I hash?

Accepted Answer

The tool processes files in chunks and can handle files of any size your browser's memory allows, typically up to 2GB or more. A progress bar shows processing status for large files. Processing speed depends on your device hardware.

Question 5

What does a hash mismatch mean?

Accepted Answer

A hash mismatch means the file you have does not match the expected hash. This could indicate: the file was corrupted during download, the file was modified after creation, or you are comparing against the wrong hash/algorithm. Re-download the file and verify again. If mismatches persist, the file may have been tampered with.

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