Same bytes, same hash
An unchanged file produces the same checksum every time under the same algorithm.
Trust the file.
Check the fingerprint.
Calculate a standard cryptographic checksum and compare it with the publisher’s value—without handing the file to another server.
Files and checksum lists never leave your device. Your browser reads them locally and uses the built-in Web Crypto API. Version 1.1.0: Load a publisher checksum list to verify several files in one pass.
01
Add the files you want to verify
Files are processed one at a time. Very large files still need enough free browser memory to be read.
The useful details01 02 03
A deterministic answer beats a confident guess.
Verify a whole release
Load the publisher’s checksum list once, then calculate every downloaded file to see which entries match.
The source still matters
Compare against a checksum delivered through a publisher channel you already trust.
Checksum questions.
Which checksum list formats are supported?
The batch checker reads common GNU lines such as hash filename and BSD lines such as SHA256 (filename) = hash. A list must use one supported SHA algorithm.
Which algorithm should I choose?
Use the same algorithm named by the publisher. SHA-256 is the most common modern file checksum. Loading a supported checksum list selects its algorithm automatically.
Does a matching checksum prove a file is safe?
It proves that your file matches the bytes represented by the expected checksum. It does not prove the original publisher or software is trustworthy, so the source of the expected value still matters.
Why is MD5 not included?
MD5 is still encountered as an accidental-corruption checksum, but it is not collision resistant enough for modern security verification. This tool keeps the main path on the SHA-2 family.
Why can a very large file take time?
The browser must read the file and perform the digest locally. This version uses the browser’s standard cryptographic API, which may hold the file data in memory while calculating.