The problem
You sent the final draft of an NDA to a client on Tuesday at 4:42 PM. Three months later, in a meeting, the client claims they received a different version — without the exclusivity clause that protects your work. Without objective proof of what existed when, the dispute reduces to one party's word against the other's — your email logs, their email logs, and no court able to establish the truth without expensive technical expertise.
ExistBefore solves this with an objective cryptographic timestamp: the attested version of the file existed at a specific instant, and this is verifiable by anyone, at any time, without trusting us.
When to attest
- NDAs sent before a disclosure: attest the version you sent in advance. If the disclosure includes sensitive information and the counterparty later claims they never accepted exclusivity, you have proof of the original text.
- Term sheets with investors or commercial partners: attest every negotiated version. Build a cryptographic timeline of clause evolution.
- Technical specifications attached to a B2B contract: the devil is often in the attachment details. Attest each attachment separately to avoid retroactive disputes about the reference version.
- Employment contracts with non-standard clauses: vesting, RSUs, non-compete agreements. Attest the signed version and every attachment to protect against unauthorized later modifications.
- Contractual emails with PDF attachments: in addition to saving the email, attest the attached PDF for proof independent of the email provider.
Integrating ExistBefore into your legal workflow
- Attest at send-time: when you send the final version of a contract, attest the file. Save the PDF certificate in the client folder.
- Email reference: in the contract transmittal email, include a line like "Attachment SHA-256: [first 16 chars]…". This cryptographically binds the email message to the content.
- Storage: archive the ExistBefore PDF alongside the contract itself. If the counterparty modifies the file, the hash no longer matches — immediate proof of alteration.
- Later verification: if a dispute arises, anyone can recompute the SHA-256 of the disputed contract and compare it with the certificate. If hashes match, the file is authentic; otherwise it has been modified.
What ExistBefore does not prove
It is essential to distinguish what the proof attests from what it does not attest:
- It does not prove authorship: it proves the file existed, not that you wrote it. Authorship requires additional elements (email history, corporate version-control, witnesses).
- It does not prove acceptance: it proves the existence of a draft, not that the counterparty accepted it. Acceptance requires signature or conclusive conduct.
- It does not replace a qualified electronic signature: ExistBefore certifies a hash, not a signature on the document. For documents that require qualified signature (e.g. CAdES, PAdES), use a certified signature solution.
- It does not replace mandatory registration: lease agreements, real-estate transfers, and other documents subject to mandatory registration retain their ordinary regime.
Legal references
- EU Regulation 910/2014 (eIDAS) — articles 41–43 on the legal effect of qualified electronic timestamps.
- UNCITRAL Model Law on Electronic Commerce — international framework for the legal recognition of electronic records and timestamps.
- U.S. ESIGN Act & UETA — recognition of electronic records and signatures in the United States; cryptographic timestamps qualify as records under §101 of ESIGN.
Frequently asked questions
Does this replace a notary?
No. ExistBefore is complementary, not a replacement. It adds an objective cryptographic proof that the attested version existed at a specific moment, regardless of the form of the contract. Acts that legally require a notarial public form still require a notary.
Is an EU-qualified eIDAS timestamp admissible in court?
Yes. ExistBefore's T1 layer includes a qualified timestamp issued by a TSA accredited under EU Regulation 910/2014 (eIDAS). Qualified timestamps benefit from a presumption of accuracy of the indicated date and time (art. 41) and are admissible as evidence in all EU Member States.
What if the other party claims a different version?
Compare the SHA-256 hashes. If your version and the counterparty's version produce different hashes, at least one was modified after attestation. The T1 timestamp proves which version already existed at a given date — the party claiming a later version bears the burden of explaining when and how it was created.
Can I prove the content without revealing it?
Yes. SHA-256 is a one-way function: it reveals only that a specific file existed, not its content. You can attest a confidential contract and show the judge (or counterparty) the PDF certificate with hash + timestamp. The contract itself remains confidential until you choose to disclose it.
How long is the proof valid?
T0 (ECDSA signature) is valid for as long as the public key remains verifiable. T1 (eIDAS timestamp) is valid for the TSA's signature lifetime, typically 5–10 years, after which it can be re-stamped. T2 (Bitcoin anchor) provides decade-scale validity: the proof exists as long as the Bitcoin chain exists.
Can I attest attachments and intermediate drafts?
Yes. Each file produces a separate attestation. Best practice is to attest every significant version of a contract under negotiation (initial draft, counterparty mark-up, final version) to build a verifiable temporal sequence of the document's evolution.
Ready to attest your contract?
The content stays on your device. Only the SHA-256 hash (32 bytes) is transmitted.