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Digital Signature & Blockchain

Full Digital Proof
for Your Business

Electronic signature with e.firma SAT, public blockchain timestamping, and NOM-151 certification. Generate legal evidence with the highest probative force recognized by Mexican law.

The Problem: Materiality Before the SAT

The SAT no longer accepts just invoices and payment receipts. Since the reform of Art. 69-B of the Código Fiscal de la Federación, it demands the economic substance behind every transaction: contracts, deliverables, work logs, photos, emails — all with a provable date.

The problem is that any company can create a contract today and backdate it six months. Without a verifiable date, the SAT can presume your transactions are simulated (EFOS) and disallow your deductions.

SureSeal solves this. Every document you seal is registered on a public blockchain with immutable date and time. You no longer depend on someone believing you — the evidence is verifiable by anyone.

How It Works

1

Upload your document

Upload the PDF to SureSeal. The system calculates a unique digital fingerprint (SHA-256 hash). Any change to the document generates a completely different fingerprint.

2

Digital signature

The signer uses their e.firma from the SAT, binding their RFC to the document irrefutably. OTP-based signature is also supported for quick acceptances.

3

Blockchain sealing

The fingerprint of the signed document is registered on Polygon, a public blockchain. No one controls the network, no one can alter previous records.

4

Public verification

Anyone can verify the document by scanning a QR code or dragging the file to the verification page. The document is never uploaded to the server — the fingerprint is calculated in the browser.

Three Levels of Protection

Not all documents need the same level of protection. SureSeal lets you protect entire case files at a reasonable cost.

Level 1 — Blockchain

Proof of Existence

The document fingerprint is registered on a public blockchain. Proves it existed on that date with that exact content.

Ideal for: progress photos, emails, meeting minutes, work logs, screenshots, internal reports.

Level 2 — e.firma + Blockchain

Consent + Existence

The signer uses their e.firma from the SAT. It records who approved, what they approved, and when they approved it, with their RFC linked.

Ideal for: service agreements, deliverable acceptances, purchase orders, amendment agreements, closing documents.

Level 3 — e.firma + Blockchain + NOM-151

Full Protection

In addition to e.firma and blockchain, a NOM-151 certificate is issued through a Certification Service Provider accredited by the Secretaría de Economía.

Ideal for: main contracts, final case file packages, high-value transactions, cases likely to end in litigation.

Legal Framework

SureSeal does not operate in a legal vacuum. Blockchain and electronic signatures have explicit recognition in Mexican legislation.

Law / Standard What it establishes Relevance
CNPCF Art. 350 Information on public blockchain constitutes full legal proof. Same probative force as public deeds and notarial instruments.
CFF Art. 69-B SAT presumes non-existence of transactions without evidence. What makes materiality documentation mandatory.
Código de Comercio Arts. 89-114 Electronic signature has the same legal effects as a handwritten signature. Legal validity of e.firma SAT on documents.
NOM-151-SCFI-2016 Requirements for preserving data messages with integrity. PSC certificates with additional probative force.

Key fact: If someone challenges blockchain-backed evidence, the burden of proving it was compromised falls on the challenger (Art. 350 CNPCF). Given the nature of public blockchain, this is virtually impossible.

Complete Materiality Case Files

SureSeal doesn't just protect individual documents — it lets you create projects that group all documents of a transaction under a single case file. At the end, a ready-to-present evidence package is generated for the SAT, auditors, or a judge.

Document Protection level
Main contractLevel 3 — e.firma + Blockchain + NOM-151
Deliverable acceptancesLevel 2 — e.firma + Blockchain
Purchase ordersLevel 2 — e.firma + Blockchain
Progress photosLevel 1 — Blockchain
EmailsLevel 1 — Blockchain
Internal meeting minutesLevel 1 — Blockchain
Invoice + payment receiptLevel 2 — e.firma + Blockchain
Final case file packageLevel 3 — e.firma + Blockchain + NOM-151

In a typical case file with 14 document types, only 2 need Level 3 (NOM-151). About 6 carry e.firma (Level 2) and the other 6 use blockchain only (Level 1). This dramatically reduces cost without sacrificing legal certainty.

Why SureSeal?

vs. Traditional Notary

A notary charges thousands of pesos to certify a single document. SureSeal seals hundreds of documents at a fraction of the cost, in minutes instead of weeks. It doesn't replace notaries for acts that legally require public faith — for everything else, it's the digital alternative.

vs. DocuSign and Similar

SureSeal stamps on a public blockchain with full legal proof under Mexican law (Art. 350 CNPCF). It uses e.firma SAT linked to the RFC, not just an email. It offers NOM-151 certification that no foreign platform provides. And verification is done without uploading the file to the server.

vs. Doing Nothing

Without a provable date, the SAT can argue you fabricated evidence after the fact. Without sealing, a judge can question the integrity of your documents. The cost of an adverse audit or lost lawsuit is incomparably greater than protecting your documents.

Industries We Protect

Tax / SAT

Complete materiality case files with provable dates to demonstrate the economic substance of your transactions.

Legal

Contracts, records, and communications with evidence carrying the same probative force as notarial instruments.

AML / Compliance

Supporting documentation to justify origin and destination of funds under anti-money laundering obligations.

Audit

Verifiable integrity of financial statements, work papers, and supporting documents.

Foreign Trade

Customs declarations, invoices, and logistics with evidence that declared operations and costs are real.

Healthcare

Prescriptions, informed consents, and clinical records protected with digital signature and immutable sealing.

Construction

Progress photos, construction logs, and delivery records with verifiable provable dates.

ESG / Sustainability

Reports, certifications, and environmental commitments with verifiable compliance evidence.

Frequently Asked Questions

Does my counterparty need to understand blockchain?

No. They receive a PDF with a QR code. They scan it and verify with one click. No wallet, no special software.

Does it replace the notary?

Not for acts that legally require public faith. Yes, for thousands of transactions where no one goes to a notary due to cost or time. They are complementary.

What happens if someone alters the document afterward?

Any modification, however small, generates a different fingerprint. When verifying, the system detects it doesn't match the blockchain record. The alteration is automatically exposed.

Are the documents exposed?

No. What is registered on blockchain is the digital fingerprint (hash), not the document. It is mathematically impossible to reconstruct the document from its fingerprint. Your files remain private.

Is it only valid in Mexico?

The cited legal framework is Mexican, but blockchain sealing is globally verifiable. Blockchain has no borders — anyone in any country can verify the document's authenticity.

Protect Your Operations Today

Schedule a personalized demo and discover how SureSeal can safeguard the materiality of your operations.

Request a Demo