What this tool does
- Any file goes in: a PDF, an image, an archive, an executable, a file we would not know how to open. There is nothing to understand in order to work out a checksum.
- Paste the published checksum in whatever form you found it: uppercase, with spaces, prefixed with “sha256:”, or the whole line printed by sha256sum.
- Two files dropped in together are compared with each other: that is how you check that two exports from this site are identical bit for bit.
- The list saves in sha256sum format, which “sha256sum -c” knows how to read: what you take away can be checked elsewhere, with a tool that is not ours.
- SHA-256 only. MD5 and SHA-1 are broken for collisions, and offering them “for compatibility” would be selling a check that proves nothing.
What it does not do: A matching checksum does not say a file is SAFE: it says it is THE SAME as the one you hold the checksum for. If the published checksum is wrong, or published in the same place as a compromised file, it will confirm it faithfully — that is the limit of the exercise, not of this tool. An empty file is refused rather than hashed: its checksum is valid and identical for every empty file in the world, which would make two interrupted downloads look identical. And as everywhere here, the ceiling is a hundred megabytes: everything happens in the tab.
Nothing is uploaded. Cut your network connection once this page has loaded: the tool keeps working. How to check it yourself.
The other tools
- Merge PDFs: Several files, one document, in the order you decide.
- Organize pages: Reorder, rotate, delete, duplicate: the whole plan.
- Extract pages: Pick pages, take them out into a document of their own.
- Delete pages: Remove pages while looking at them, and they do not survive under the file you get.