The SHA-256 hash on the cover page, explained
A hash is a short fingerprint of a file. It shows that two files are identical, and nothing more.
The SHA-256 hash on a Nispach cover page is a 64-character fingerprint of the original WhatsApp export file. If even one character in that file changes, the hash changes completely. Anyone holding the original export can compute its SHA-256 with standard tools on Windows, Mac or Linux and compare it to the cover page, confirming the appendix was built from that exact file. The hash does not prove that the chat itself is genuine or complete; it ties the appendix to a specific source file, which can then be examined.
What a hash is
SHA-256 is a standard algorithm that reads a file and produces a fixed-length string of 64 hexadecimal characters. The same file always gives the same hash. A file that differs by a single character gives a completely different one. It is not practical to make a different file with the same hash.
What it proves, and what it does not
It proves that the appendix was produced from the file with that hash. If the original export is kept, anyone can check this later.
It does not prove that the messages in the export are genuine, that nothing was deleted on the phone before export, or who wrote them. Those are questions about the chat and the phone, for the evidence and the affidavit.
How to check it yourself
On Windows, open PowerShell and run Get-FileHash file.zip -Algorithm SHA256. On Mac or Linux, open Terminal and run shasum -a 256 file.zip. Compare the result with the hash printed on the cover page.
Keep the original file unchanged
Opening the .txt in a text editor and saving it, or unzipping and re-zipping the export, changes the file and therefore the hash. Keep the export exactly as it came from the phone, alongside the appendix.
Turn the export into an appendix
Drop in the WhatsApp export and preview the first three pages for free. The chat stays on your computer.
Start with your email
Email only. We send the link to start and nothing else.
FAQ
Is the hash of the PDF or of the export?
Of the original export file you dropped in. That is what ties the appendix to its source.
Is a hash the same as a digital signature?
No. A hash identifies a file; a digital signature also identifies who signed it. Nispach records the hash only.
Does computing the hash upload the file?
No. The hash is computed in your browser, on your computer.