File Verifier

A checksum is a fixed-length value calculated from every byte in a file. Rename the file and the checksum stays the same. Change the contents and it changes. Checksum, hash, and digest all name the same value.

A download can stop partway, get corrupted in transfer, or be modified along the way, and none of that is visible in the file itself. Compare its SHA-256 with the checksum published by whoever released the file: a match means you have the bytes they published. It confirms the file, not the source.

Choose or drop a file, and the File Verifier calculates all four checksums in your browser. To check one, select Paste checksum and paste the value published with the file. The algorithm is detected from its length, and the result shows match or mismatch, highlighted from the first character that differs.

The bytes you have aren’t the bytes that checksum was calculated from. A download that stopped partway is the usual cause, so delete the file and download it again from the original source. If a fresh copy still doesn’t match, check that the published checksum belongs to the same version, then contact whoever provided the file.

Yes. Choose or drop a file, select Compare file, then choose or drop a second file. Both files get all four checksums, with match or mismatch shown per algorithm. Names, folders, and timestamps are ignored, so two copies saved under different filenames still match.

In principle, yes. A checksum has a fixed number of possible values while files don’t, so collisions have to exist. For SHA-256, the odds of hitting one by accident are lower than the odds of your disk misreading the file. MD5 and SHA-1 are different: collisions can be constructed for both on purpose, which is why neither is safe for a security check.

Use SHA-256 when the source provides it. Kurodyne uses it for package records. An MD5 or SHA-1 match can’t rule out tampering.

It means the file you checked matches, byte for byte, the package of an approved release of a product currently listed in the Catalog. Sign in, then choose or drop a ZIP file to check its SHA-256 checksum against those packages. A product that is hidden or no longer for sale doesn’t match. A match shows you the product and tells you if the seller has published an update since then. Calculating checksums needs no account. Matching a package does.

Your file isn’t uploaded. Every checksum is calculated in your browser. While you are signed in, the SHA-256 checksum of a ZIP file is sent to Kurodyne so it can be matched against packages of products currently listed in the Catalog (see “Verified package”). That is 64 characters of text, never the file itself.

Yes. No account or signup is required. Checksums are calculated in slices, so the File Verifier sets no file size limit. Signing in adds package verification for ZIP files.