Don’t just trust us. Check.
Every time Yupzap deletes a delivered message from its servers, and every time someone’s encryption key changes, a record goes into a public log that can only grow. Nobody, not even Yupzap, can quietly edit or remove a line without it showing. Every check on this page runs in your browser. The log never contains messages, names or phone numbers.
Live log
- Deletion log records
- …
- Key directory records
- …
- Latest signed root
- …
- Last updated
- …
- Signature
- Checking…
- Since your last visit
- …
- Witnesses
- Witness seals: coming soon
Check a message
In Yupzap, long-press a message, open Message info and copy its verification code. Paste it here. This page fetches the proof and checks it in your browser.
The code is a fingerprint of "this message copy was removed". It does not contain the message. The check finds the fingerprint in its hourly batch, recomputes the path up to the signed root of the log, and checks the log's signature with the public key on this page. If any step fails, the page says so.
■ your record ■ proof path ■ other records
Check a contact
Every encryption key added to a Yupzap account, changed or signed out goes into a public key transparency directory that can only grow, so nobody can swap in a fake key without it showing up here. Your phone checks your contacts’ keys on its own. You can also check one here.
Live log stream
What the public sees, as it happens. Only fingerprints. You cannot tell who sent what, to whom, or when a particular person was online. Every line is checked in your browser before it is shown.
The log at a glance
These numbers come from our signed public logs and are checked in your browser.
| Right now | Count |
|---|---|
| Hourly deletion batches in the log | … |
| Message copies removed, in the batches shown in the stream | … |
| Key records in the key directory | … |
| Key changes and sign outs recorded | … |
| Messages, names or phone numbers in the log | 0, never stored |
| Independent witness signatures | Coming soon |
A removal that has not happened yet shows as "Removal pending" in Message info, for example while the other phone is offline. A message is never shown as removed when it was not.
Our promises, in plain words
We can’t read your chats
Guardian locks one-to-one messages on your phone and unlocks them only on the other person’s phone. Yupzap never has the keys.
Deletion you can check
When we remove a delivered message copy, it is recorded here. If it has not been removed, Message info says "Removal pending", never a false tick.
No secret key swaps
Every key change is logged in public, and your chat shows a notice when a contact’s security code changes.
Technical details
How verification works
- Every deletion is added to an append-only log.Each removed message copy becomes a fingerprint, grouped into an hourly batch. Key changes go into a second log the same way.
- Each hour the server signs a checkpoint of the log.The checkpoint states the size of the log and the root of its hash tree, signed with the log’s signing key.
- Your browser checks the signature with our public key.The public verification key is built into this page, so a forged checkpoint is rejected.
- It proves your record is included without revealing anything about you.A short hash path links your record to the signed root. The proof holds fingerprints only.
| Standard | RFC 9162 Merkle tree (SHA-256) |
|---|---|
| Checkpoint format | Signed note (C2SP tlog-checkpoint) |
| Signature | Ed25519 |
| Deletion log origin | transparency.yupzap.com/deletion/v1 |
| Deletion log public verifier key | transparency.yupzap.com/deletion/v1+65a7fda0+Aaxh631+D9zWiH4Ty3OFUs4w6kcQdhoJ2JM/jcdS5saP |
| Key directory origin | yupzap.com/guardian/keys |
| Key directory public verifier key | yupzap.com/guardian/keys+39808756+AZCuHfdMup+/DbGqaUz7gB2uh/Ag7nDA9q5fg64rwmQ7 |
These are public verification keys. Signing keys never leave our servers.
Yupzap is a product of Merdot. Guardian by Merdot. This page makes no tracking requests and sets no cookies. It stores the last checkpoints it saw in your browser for the checks above.