Frequently asked questions

Not only. Bitcoin is first and foremost a large, unforgeable global ledger, shared by thousands of independent computers. Proxae records the fingerprint of your document in it — no financial value, no transaction. It is the same technology, used for proof rather than exchange.

No. Technically impossible. Once inscribed in a Bitcoin block, no actor — not even Proxae, not even Bitcoin miners — can modify the timestamp without invalidating the entire chain that follows, which would require controlling 51% of global computing power.

Your fingerprint remains in the global registry, but you can no longer match it to your content. The proof exists — you just can't present it. That's why we insist so strongly on keeping your original file in multiple locations.

Yes. PDF, Word, image, video, audio, source code, ZIP archive, text — any file up to 50 MB is accepted. We recommend PDF for its stability: a PDF copy is always identical to the original, unlike some formats that can subtly change.

Between 1 and 3 hours in general. The Bitcoin network produces a new block approximately every 10 minutes. Proxae automatically checks and updates your status upon confirmation.

That's a legitimate question. Proxae's impact on Bitcoin is infinitesimal: millions of fingerprints are grouped into a single transaction thanks to the OpenTimestamps protocol. Proxae adds virtually no additional transactions to the Bitcoin network.

Yes, but with an important caveat: any difference in spaces or characters during future verification will produce a different hash. For legal or important use, always create a PDF. For a simple prediction, plain text is sufficient.

Proxae certifies the existence of a hash at a date — not the identity of the submitter. To link the proof to your identity, create a Pro account and enable identity verification. Your certified identity will appear in the PDF certificate.

Yes. We don't store your content — only its fingerprint. If you have an account, you can request deletion of your data at any time. Fingerprints in Bitcoin cannot be deleted, but they contain no personal data.

It's your proof certificate. A binary file of approximately 500 bytes containing the mathematical path linking your fingerprint to a specific Bitcoin block. Standardized, open-source, verifiable by anyone via OpenTimestamps CLI or at opentimestamps.org.

A .tsr (Time-Stamp Response) file is the raw response issued by the Sectigo certification authority under the RFC 3161 protocol. It contains the timestamp cryptographically signed by Sectigo, proving that at the exact moment of issuance, your fingerprint already existed. This is the file you can independently verify with openssl.

The sectigo-chain.pem file contains Sectigo's certificate chain — the public keys used to verify that the .tsr was indeed signed by Sectigo and not by anyone else. Without this file, openssl cannot validate the authenticity of the timestamp. It is included in the download bundle.

It summarises all information about your proof in a machine-readable format: identifier, SHA-256 fingerprint, creation date, confirmed Bitcoin block, and verified identity if applicable. It is the entry point for any integration or automated verification, without having to parse binary files.

Your proofs are permanent. The Bitcoin registry is decentralized — no company, no government can remove it. Your .ots file is enough to verify your proof forever, without Proxae, on opentimestamps.org or via CLI.

No. The .ots file, the .tsr, or the PDF certificate are public on your proof page — but they are worthless without your original file. A timestamp certificate proves that a fingerprint existed at a given date, not that you own the corresponding content. To constitute valid proof, both are required: the certificate and the original file you certified. Without that file, it is impossible to recompute the fingerprint and therefore to prove anything. You hold the half that matters.

Proxae offers a full REST API. Create an API key from your account settings, then use it to submit proofs, check their status and list your certifications programmatically. Full documentation with cURL examples is available on the Developers page.

Webhooks notify you automatically when a proof is confirmed on Bitcoin. Set up a receiving URL in your settings and Proxae will send a signed HTTP request (HMAC-SHA256) on each confirmation. If delivery fails, 3 automatic retries are made. You can also manually replay a delivery via the API.

Yes. Proofs created via the API get exactly the same features as those created from the web interface: Bitcoin anchoring for all accounts, and for Pro accounts, eIDAS qualified timestamping (RFC 3161, Sectigo) and automatic PDF certificate.

The European eIDAS regulation recognizes certain timestamps as having the same legal value as a notarized act. Sectigo's RFC 3161 timestamp is qualified under ETSI EN 319 422, giving it maximum probative force before European courts.

Bitcoin anchoring mathematically proves the anteriority of a document — verifiable by anyone, without a trusted third party. For most uses (intellectual property, ideas, correspondence) it is more than sufficient. For contracts, the Pro version adds European legal recognition.

Yes, with no commitment or fees. Cancellation takes effect at the end of the current period. Your Pro proofs remain accessible and verifiable even after cancellation.

Proxae never receives your raw content — the hash is computed in your browser (SubtleCrypto). For Pro encrypted content, AES-256-GCM encryption is performed client-side before upload. We cannot read your data.

Yes. Create your API keys from your account settings and integrate Proxae into your application. Submit proofs, check their status and receive notifications via webhooks — everything is documented on the Developers page.

Identity verification is entirely optional — Proxae does not need it to work. It is there for you: once your identity is certified via Stripe Identity, your name is cryptographically linked to your proof and appears in the PDF certificate. In the event of a dispute, you can prove that it was you — and no one else — who performed this certification on that date.