Quick answer
Understand SHA-256 hashes, file integrity checks, local hashing, and what a checksum can and cannot prove.
Use the related browser-only tool after reading the safety notes, then verify the output before sharing.
What SHA-256 proves
SHA-256 is useful for checking file integrity, comparing downloads, and confirming that a file matches a published checksum. Even one byte changing creates a different hash.
A checksum is often shown as a 64-character hexadecimal string. If your calculated value exactly matches a trusted published value, the file bytes match that published reference.
What it does not prove
A checksum does not prove a file is safe, legal, original, trustworthy, or malware-free. It only describes byte identity. A malicious file can still have a valid checksum if the attacker publishes the checksum too.
A hash can also reveal whether two files are identical. Do not share hashes of private files publicly if matching that exact file would create a privacy risk.
Why local hashing is useful
Browser Web Crypto can calculate the digest locally so the selected file does not need to leave your device. This is useful when you want to verify a download without uploading the file to a checksum website.
Large files can take longer to read, and browser memory limits vary by device. A progress message helps users understand that the browser is working locally.
Safe verification workflow
Copy the expected SHA-256 value from the official source, calculate the hash locally, compare the values exactly, and download the file again from the official source if they do not match.
If the checksum is published on the same untrusted page as the suspicious file, it does not provide strong assurance. Prefer checksums from the official publisher and secure distribution channels.
FAQ
Why is my hash lowercase?
Lowercase hex is a common normalized display format. Uppercase and lowercase represent the same hex value.
Can I hash text instead of a file?
This launch tool focuses on file hashing. Text hashing can be added later.
Does a matching hash mean the file is safe?
No. It means the bytes match the expected value. Safety requires separate trust and security checks.