For Founders, IP Lawyers, M&A Advisors and Corporate Dev Teams
They’ll claim it wasn’t this version of the NDA. Prove it was.
Lock the signed NDA at the moment of execution. EU qualified timestamp + Bitcoin OpenTimestamps. Court-admissible in 10 seconds.
Six months after the deal, the counterparty produces “the version we actually signed” — without the carve-out, without the residuals clause, without the term you spent two weeks negotiating. Email metadata is falsifiable. DocuSign Personal does not include qualified timestamps. Your screenshot is worthless in court.
Drop the signed PDF into ProofSnap File Certifier. SHA-256 is computed locally in your browser. Only the 32-byte hash leaves your device — the NDA itself never uploads. Receive a 10-file court-admissible evidence ZIP. Bitcoin OpenTimestamps anchoring is always included on every plan (court-admissible under US FRE 901). Add an EU qualified timestamp (eIDAS Art. 41(2) presumption of accuracy, burden-of-proof reversal in all 27 EU member states) when the stakes justify it.
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Help me choose
10 seconds per NDA · File never leaves your device · Recognised in all 27 EU member states
Qualified timestamp issued by Disig a.s. · QTSP on the EU Trusted List · ETSI EN 319 421/422 compliant
Quick answer
How do you prove which version of an NDA was actually signed?
Drop the signed NDA into ProofSnap and you get a court-ready evidence ZIP in 10 seconds — one that proves, to any judge, exactly which version was signed at exactly what time. Your NDA file never leaves your device. From ~$1.66 per file with Bitcoin proof, or $6.99 with EU qualified timestamp.
Technical detail: SHA-256 is computed locally in your browser and anchored to the Bitcoin blockchain via OpenTimestamps (always on, free on every plan). Optionally add a Disig eIDAS qualified timestamp (RFC 3161) for a legal presumption of accuracy under eIDAS Article 41(2) across all 27 EU member states. The resulting 10-file evidence ZIP is self-authenticating under US Federal Rules of Evidence 902(13)/(14) and verifiable by anyone with the free ProofSnap Trust Verifier. DocuSign QES typically costs $10–$20 per signature; ProofSnap eIDAS SnapPack starts at $6.99 per stamp, and plain SnapPack $4.99 bundles 3 Bitcoin-only file certs + 10 page captures.
Four ways your NDA loses its teeth
None of them are your fault. All of them are preventable in 10 seconds.
“We signed a different version”
Six months after the term sheet falls apart, the counterparty produces v0.2 of the NDA — without the carve-out you negotiated in v0.3. You have the signed v0.3 in your inbox. They claim it never existed. Email timestamps are admissible but trivially falsifiable; metadata can be stripped or rewritten.
DocuSign Personal doesn’t include qualified timestamps
Most founders use DocuSign Personal or Adobe Sign Standard. Qualified Electronic Signatures (QES) with eIDAS qualified timestamps are an Enterprise add-on. Your executed NDA has a signature audit trail, not a court-presumed timestamp. The version stays vulnerable.
VC diligence: “Show me the timestamp on the executed version”
2026 diligence checklists now ask which agreement version governed which disclosure. If your IP, your customer list, or your pitch deck was shared under an NDA, the investor wants to know which version was in force. Inconsistent or unverifiable NDAs slow deals and damage credibility.
Tesla lost online contract enforceability for this reason
In Nager v. Tesla, the court found Tesla’s online contract terms unenforceable because Tesla could not produce evidence connecting specific customer acceptance to the terms in force at that moment. Without per-version records, the agreement collapsed. The same risk applies to every NDA you sign without a qualified timestamp.
Who should lock every NDA
If you sign NDAs to protect IP, term sheets, customer data, or trade secrets — this is your insurance against the “wrong version” argument.
First-time founders pre-Series A
10–50 NDAs per fundraise. Investors, advisors, contractors, prospective hires. No legal team yet. The first NDA dispute can cost $50K–100K in legal fees and weeks of distraction at exactly the moment you cannot afford either.
With ProofSnap: drop each signed NDA into File Certifier as it comes back. Bulk-certification ZIP. Total cost for a Series A round (50 NDAs): two eIDAS SnapPack 10s = $99.98. Less than one hour of an associate’s time.
IP & patent lawyers (outside counsel)
Every disclosure carries a versioning risk. Client sends invention disclosure, you send NDA, prospect signs, returns. Six months later: trade secret leak claim. Which NDA version governed that disclosure? Without a qualified timestamp, you are relying on the client’s email archive.
With ProofSnap: certify every executed NDA the same day it comes back. Recurring billable workflow. EU qualified timestamp + Bitcoin OpenTimestamps. Self-authenticating under FRE 902(13)/(14) without expert testimony.
M&A boutique advisory
Deal-flow NDAs accumulate fast. A typical mid-market mandate: 30–100 NDAs across teasers, CIMs, management presentations. Six months after the deal closes (or breaks), one signer claims they received material under a different NDA. Reputational risk if you cannot prove which version applied.
With ProofSnap: bulk-certify all deal NDAs per mandate. Company plan ($18.99/seat/month) gives unlimited file certifications + admin dashboard. Per-deal cost: under $20.
VC associates & corporate dev
You sit on both sides of the table. Inbound: hundreds of one-way NDAs from founders pitching you. Outbound: mutual NDAs for portfolio diligence and partnerships. Audit trail matters at exit: which version of which NDA governed which disclosure?
With ProofSnap: certify every NDA on receipt. Build a clean per-quarter archive without burdening legal ops. 5-seat Company plan = $94.95/month = $20K+ cheaper than Page Vault Team for the same volume.
From signed PDF to court-admissible ZIP in 10 seconds
Drop. Certify. Verify. No upload of the NDA itself, no IT department, no account required for anyone to re-check your certificate later.
Drop and Certify
Inside the ProofSnap sidebar
Open the File Certifier panel. Drag your signed NDA in — any file up to 100 MB. Toggle EU Qualified Timestamp (eIDAS) if you want legal presumption. Click Certify File.
Certificate ready — 10 seconds
SHA-256 + Bitcoin + Disig eIDAS
SHA-256 is computed in your browser — only the 32-byte hash leaves your device. Bitcoin OpenTimestamps anchored. Disig eIDAS qualified timestamp sealed. Click Download Certificate Package.
Anyone can re-verify, anytime
Judge. Opposing counsel. Auditor.
Hand the ZIP to anyone. They drop it into the free ProofSnap Trust Verifier, drop the original NDA next to it, see “File matches certificate”. No ProofSnap account required.
What’s inside the evidence ZIP — 10 forensic files
manifest.json — evidence ID + SHA-256 hashmanifest.sig — RSA-4096 signaturepublickey.pem — verifier public keychain_of_custody.json — ISO 27037 custody recordforensic_log.json — hash-chain event logprovenance_certificate.pdf — human-readable certificatemanifest.json.ots — Bitcoin OpenTimestamps proofmanifest.json.tsr — eIDAS qualified TSR (RFC 3161)eidas_validation.json — LTV validation data[your_NDA].pdf — original file (embedded)No vendor lock-in. If ProofSnap disappeared tomorrow, your evidence ZIP would still verify against Bitcoin and Disig with open tools.
Try the File Certifier — 7-day trialBuilt-in vs premium · recognised across EU, UK, US
Two layers of proof. Choose your weight.
Every File Certifier ZIP is anchored to the Bitcoin blockchain — on every plan, including the 7-day trial. Add an EU qualified timestamp when the dispute is worth it.
Layer 1 — Bitcoin OpenTimestamps
Included on every plan · or standalone via SnapPack $4.99 (3 file certs + 10 page captures)
SHA-256 hash of your signed NDA, anchored to the Bitcoin blockchain via OpenTimestamps. Decentralised, independent, tamper-evident. Once anchored, the hash cannot be forged without breaking Bitcoin itself.
- Cryptographic proof of existence at time T
- US FRE 901 tamper-evidence + chain of custody
- Accepted as corroborating proof in US IP & contract disputes (federal court decisions 2024–2026)
- Verifiable with open tools — no ProofSnap dependency
- No EU legal presumption — opposing party can still challenge accuracy
Sufficient for: most US disputes, internal audit trails, fundraise NDAs where the risk of dispute is low, scope-creep freelance evidence.
Layer 2 — eIDAS qualified timestamp
Optional · from $6.99 per stamp
Disig a.s. (QTSP on the EU Trusted List) issues a qualified timestamp under RFC 3161 + ETSI EN 319 421. Adds the highest evidentiary weight EU law provides — a legal presumption that reverses the burden of proof.
- Everything in Layer 1, plus:
- eIDAS Art. 41(2) legal presumption of accuracy
- Burden of proof reversal — counterparty must rebut
- All 27 EU member states recognised (Art. 41(1))
- UK eIDAS (post-Brexit retained) maintains the presumption
Required for: EU cross-border NDAs, M&A diligence, IP licensing, GDPR audits, any dispute where you want to shift the burden of proof onto the other side.
EU · 27 member states
eIDAS Art. 41(2) grants qualified timestamps a legal presumption of accuracy. Directly applicable, no transposition. Issued via Disig a.s. — QTSP on the EU Trusted List.
UK · post-Brexit retained
UK eIDAS + Electronic Communications Act 2000 maintain the same qualified-timestamp presumption. Useful for cross-border NDAs, M&A, IP licensing between EU and UK parties.
US · federal courts
FRE 902(13)/(14): cryptographic records produced by a reliable process are self-authenticating. Blockchain hashes accepted as corroborating proof (2024–2026 federal decisions).
What this means at trial
Without a qualified timestamp
You must prove the executed NDA is the one in force, and that it has not been altered. Email metadata, witness testimony, file timestamps — all challengeable. Weeks of discovery, expert reports. Median contract dispute cost ~$91K (RocketLawyer 2024). Legal fees in trade-secret matters average $150K–$500K (Stout). And while 81% of federal trade-secret cases that reach a verdict favor the plaintiff (Stout Trends in Trade Secret Litigation), that only matters if you can authenticate which version of the NDA actually governed the disclosure.
With a ProofSnap qualified timestamp
The court presumes the accuracy of your timestamp (eIDAS Art. 41(2)) and the integrity of the bound data. The opposing party must prove your timestamp is inaccurate. No expert testimony required to authenticate (FRE 902(13)/(14)). Most version disputes end before trial.
Why is eIDAS optional? In one sentence:
Because Bitcoin OpenTimestamps already produces a tamper-evident, court-admissible record that satisfies US FRE 901 and corroborates existence at time T — you only need eIDAS when you want the opposing party to carry the burden of proof instead of you. For a $2K NDA fundraise round, Layer 1 is usually enough. For a $20M M&A NDA or an EU cross-border IP dispute, Layer 2 is worth every dollar.
ProofSnap is not a law firm and does not provide legal advice. Qualified timestamps are issued by Disig a.s. (QTSP on the EU Trusted List). Consult a qualified lawyer for advice on your specific dispute.
Pay per NDA, or subscribe
Every plan includes Bitcoin OpenTimestamps anchoring. Add eIDAS qualified timestamps when needed.
Not sure which to pick? Pick by stakes & volume.
Bitcoin proof only
Low-stakes NDAs — 3 file certs + 10 page captures in one pack.
~$1.66/cert · no EU presumption.
SnapPack — $4.99 ↓One high-stakes NDA
EU qualified, single signing, M&A teaser or critical hire.
eIDAS Art. 41(2) presumption.
eIDAS SnapPack 1 — $6.99 ↓5–10 NDAs (fundraise round)
Pre-Series A, deal cycle, batch.
EU qualified, $5/cert.
eIDAS SnapPack 5 — $24.99 ↓Ongoing volume (5+/mo)
IP firm, M&A boutique, corporate dev.
Monthly file-cert quota.
Subscribe — from $16.99/mo ↓eIDAS SnapPack — pay-per-NDA
Buy credits, certify when you need to. Credits valid 12 months.
Or subscribe (for ongoing NDA volume)
For IP lawyers, M&A advisors, corporate dev teams with monthly volume.
Every plan ships Bitcoin OpenTimestamps anchoring by default. eIDAS qualified stamps are an optional premium layer — included on Enterprise/Company, available via eIDAS SnapPack on Professional.
Professional
or $160/year (20% savings)
- 15 file certifications / month
- Bitcoin OpenTimestamps on every cert
- eIDAS optional — add eIDAS SnapPack
- Unlimited page captures
- Forensic ZIP with chain of custody & provenance PDF
For: solo freelancers, regular NDA volume without EU presumption need
Enterprise
or $280/year (20% savings)
- 50 file certifications / month
- Bitcoin OpenTimestamps on every cert
- 10 eIDAS qualified stamps / month (optional layer)
- Unlimited page captures
- Forensic ZIP with chain of custody & provenance PDF
For: solo IP lawyers, founders running diligence, consultants
Company
or $190/seat/year (20% savings) · min 2 seats
- Unlimited file certifications
- Bitcoin OpenTimestamps on every cert
- 5 eIDAS stamps / user / month (optional layer)
- 2–10,000 seats, admin dashboard
- Forensic ZIP with chain of custody & provenance PDF
For: IP law firms, M&A boutiques, corporate dev teams
5-seat example: $950/year. 25 eIDAS stamps/month. ~$3.17 per stamp.
7-day trial requires a credit card. Cancel anytime within the trial — no charge.
Need only 5 certs/month? Essential $8.99/month also includes Bitcoin OpenTimestamps anchoring.
SnapPack
Bitcoin proof only — no eIDAS$4.99 for 10 page captures + 3 bonus file certifications. Use captures for web evidence, file certs for signed PDFs/DOCXs — two separate pools, no sharing. Effective ~$1.66 per file cert.
Each file cert is anchored to Bitcoin OpenTimestamps (US FRE 901 tamper-evidence) and ships in the full 10-file forensic ZIP. No eIDAS qualified timestamp — for EU Art. 41(2) legal presumption, use an eIDAS SnapPack above.
eIDAS quota is shared. On Enterprise (10/mo) and Company (5/user/mo), eIDAS stamps are shared between page captures and file certifications. Bitcoin OTS anchoring keeps working when eIDAS runs out.
Two layers, two pack types. Plain SnapPack ($4.99) gives 10 page captures + 3 bonus file certs (Layer 1: Bitcoin OpenTimestamps only). For EU Art. 41(2) presumption (Layer 2), use an eIDAS SnapPack — those stamps work on both layers and on either page captures or file certifications.
Typical scenarios
During a Series A round we signed 22 NDAs with prospective investors, advisors, and a couple of late hires. Locking each one with ProofSnap as it came back took 30 seconds. We never had a dispute — but the day a lead investor’s associate asked “under which NDA did we share the deck on March 4?”, I had a SHA-256-anchored, eIDAS-stamped ZIP for it in my Drive. Conversation took 90 seconds. Without it, would have been a half-day email archaeology.
Pre-Series A founder — Typical scenario
My clients are early-stage startups sending NDAs to dozens of counterparties. Used to recommend they keep email PDFs in a folder. Now I tell them: install ProofSnap, certify every executed NDA the same day it comes back, archive the ZIP. For me, it’s a defensible recommendation under FRE 902(13) without needing expert testimony to authenticate. For them, it’s a $25 insurance policy on their IP perimeter.
IP lawyer (solo practice) — Typical scenario
These are typical use-case scenarios written by ProofSnap to illustrate fit, not customer testimonials.
vs DocuSign, Page Vault, Bernstein
DocuSign proves who signed. ProofSnap proves what was signed at exactly when. They are complementary — not substitutes.
| Feature | ProofSnap | DocuSign Personal | Page Vault | Bernstein.io |
|---|---|---|---|---|
| File never uploaded | No (cloud-hosted) | n/a (page capture) | ||
| eIDAS qualified timestamp | Enterprise add-on only | No | Scale tier (quote) | |
| Bitcoin OpenTimestamps dual seal | No | No | ||
| Pay-per-use option | $6.99/stamp | Subscription only | $195/month minimum | Subscription only |
| Chrome extension | Web SaaS only | Web SaaS only | ||
| Page capture + file cert combined | No | Page only | File only | |
| ISO 27037 chain-of-custody package | 10-file ZIP | Signature audit trail PDF | Affidavit add-on | Certificate PDF |
| Entry price | $4.99 SnapPack = 3 Bitcoin certs + 10 captures · $6.99 eIDAS 1-pack | $15/seat/month | $95/month (solo) | Free trial, quote on Scale |
Comparison reflects publicly available 2026 pricing. Competitor terms may differ by region or contract.
Frequently asked questions
Lock the next NDA you sign.
The cost of one disputed version is higher than every NDA you will ever certify. Start with one stamp for $6.99 — or run the next fundraise on a SnapPack 10 for $49.99.
Lock my NDA — 7-day free trial7-day trial requires a credit card. Cancel anytime within the trial — no charge.