YOUR DOCUMENTS. YOUR KEYS.

Keep the proof.
Keep your files private.

Sign and verify locally. Protect your keys with encrypted backups.
Identify signers using public key fingerprints you have verified.

01 / Your signing key

Your keys, no sign-in required

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Create or replace a key

An encrypted backup is created first. Your password never reaches the server. Keep it separately; a lost password cannot be reset.

Backup password (minimum 12 characters)Enter your backup password againRemember this key in this browser to sign without a password later (do not enable on shared devices)

Creating a new key will not revoke the old key. After the replacement, please inform the other party of the new fingerprint through trusted channels.

Restore from your own backup

Choose an encrypted key backupBackup passwordSave in this browser and sign later without password

Switch keys saved by this browser

02 / Sign

Create a signature proof

Any file format. File contents are never uploaded. Maximum file size: 50 MiB.

Choose a file to sign

03 / Verify

Verify a file and its signer

Select original fileChoose a signature proof (JSON)Expected signer (contacts you verified locally)Or enter the expected public key fingerprint (optional)

Local verification makes no network request. Checking revocation sends only the public key fingerprint. Without a check, revocation status remains unknown.

04 / Identify signers

Remember people you have verified

Before saving, compare the complete public key fingerprint in person, by phone or through an established trusted channel. Entering a name does not verify an identity.

Contact name (stored locally)Verified public key fingerprintI have confirmed through trusted channels that this fingerprint belongs to this person

Contacts only exist in this browser. The new key will not automatically replace the existing fingerprint and needs to be rechecked and saved with a new name.

05 / Lost or compromised keys

Revoke current key

You need the private key or a recoverable backup. The original private key signs the revocation statement. Download it to share, or register it on this server. Server registration cannot be undone.

I confirm that I want to revoke the current key, including trust in the existing signature.

Import a revocation statement from someone else

You establish trust. This service does not verify names.

A signature links a file to a key. You identify the person by verifying their public key fingerprint. The signing time comes from the device, not a trusted timestamp service, so past signatures from revoked keys also show a warning. Clearing browser data removes saved keys and contacts. Restore keys from backups and verify contacts again.

Something went wrong? Report an issue

Please describe the problem, steps and expected results. The report text will be sent to the server and will not automatically attach your files or keys; please do not fill in passwords, private keys, or sensitive content in the file.

Each IP is limited to 3 times per day, reset at midnight UTC; the same network may share the quota. Report content is retained for 90 days and is not publicly displayed.

Keep the proof.Keep your files private.