Privacy and data

What we store: the SHA-256 hash of what you seal, the agreement title, the parties' public keys, the sealing date and the OpenTimestamps proof. If you type the agreement text on the site, that text is stored to enable the agreement; if you upload a file, the file never leaves your device: only its hash travels.

What we do not store: no e-mail, no password, no name. Your identity is a cryptographic key that lives in your browser. The chat between the parties is encrypted in the browser; the server only stores ciphertext.

Cookies: one session cookie (httponly, 7 days) after signing in with your key, and your language preference in your browser. No analytics, no trackers, no third parties: this site loads nothing from other domains.

Where and who: the server runs in Spain and is operated by José Luis Olivares (grants@x39matrix.org). Proofs anchored in Bitcoin are public by design and contain only hashes, never the document. A proof already anchored cannot be removed from the Bitcoin chain. For any question about your data: grants@x39matrix.org.