ExistBefore

Does ExistBefore upload my file?

No. The browser computes SHA-256 locally and sends only the hash through a server-side proxy.

Does ExistBefore prove authorship?

No. It proves that a specific sequence of bytes existed at a specific time. It does not automatically prove authorship, ownership, or IP rights.

What is the difference between T0, T1 and T2?

T0 is the immediate digital signature. T1 adds a qualified timestamp through a Merkle-tree batch. T2 adds a Bitcoin anchor for long-term public anchoring.

Can I verify without trusting the website?

Yes. You can recompute the hash, retrieve the signing public key and validate the signature independently.

Does ExistBefore store my content?

No. The original content stays on the device. The public system stores attestation evidence, not the original file or text.

What file types can I attest?

Any file: images, PDFs, audio, video, documents, code, archives. You can also paste plain text directly. The maximum file size is 2 GB. For images with EXIF data, metadata like date taken, device, and GPS are extracted and shown before attestation.

What does the PDF certificate contain?

The PDF has six functional zones: identification (date, type, preview), technical data (hash, signature, signing key ID, attestation ID, verification URLs), verification instructions (online, offline, API), legal disclaimer, extracted file metadata (with optional GPS/device exclusion), and attestation context (browser, timezone, language).

How can I update my certificate to T1 or T2?

Visit the proof status page linked in your PDF. T1 (eIDAS qualified timestamp) completes within about an hour. T2 (Bitcoin anchor via OpenTimestamps) completes within 24–48 hours. You can download the updated PDF at any time, or simply re-submit the same content — if the hash matches, you get the latest version.

Is there an API for developers?

Yes. ExistBefore is powered by the CertiSigma API. The same attestation, verification, and evidence endpoints are available for integration into legal tech platforms, document management systems, creative tools, and enterprise workflows. SDKs are available for Python and JavaScript.