What a SHA-256 Hash Proves About a Chat, and Not
A hash is a fingerprint of a file. People hear that a hash makes a chat tamper-proof, which is too strong. Here is the plain version.
Not legal advice. This page is general information. Whether a court admits or relies on a chat is for the court; convokeep does not promise admission or any outcome. Ask a qualified lawyer about your case.
What does a SHA-256 hash prove?
SHA-256 is a cryptographic hash function that produces a 256-bit value from a file. The same file always gives the same value, and changing it changes the value. If your copy matches a value recorded earlier, the copy is unchanged since the value was recorded.
What does it not prove?
- That nothing was deleted or edited before the export.
- That the conversation is genuine or complete.
- Who sent a message or when.
- That a court will accept it.
What about messages deleted before I exported?
The hash is calculated on the file you export, so it cannot reveal messages that were gone before then.
What does convokeep put in a Record PDF?
The integrity page lists the source SHA-256, the transcript SHA-256, counts and generation time in UTC. The PDF's own hash cannot sit inside the PDF, so it comes in a separate .sha256.txt file. See Chat PDF integrity hash for the commands to check it yourself.
Can I check a file without uploading it?
Yes. The hash checker calculates the hash in your browser.
Privacy
Reading the file, building the PDF and calculating hashes all happen in your browser. No chat or attachment is uploaded and there is no account. See the privacy policy and the disclaimer.
Related guides
- Verify a PDF's SHA-256 yourself
- Chat PDF integrity hash
- Screenshots vs export
- Export WhatsApp chat for submission
- Preparing chat evidence for your lawyer
- WhatsApp deleted messages in an export
Ready to try it?
Drop your exported chat file on the convokeep app for a free preview. The first 3 pages are free (watermarked, no integrity page); saving the full PDF is a one-time paid feature. No chat or attachment is uploaded: the file is read in your browser. To check later that a file is unchanged, use the hash checker.
This document was generated locally in the user's browser; no content was uploaded.