In a world where digital documents have become the standard, ensuring the integrity and legal timestamp of a contract has become a critical need for businesses, freelancers, lawyers, and anyone signing important agreements online.
Fortunately, blockchain technology is here to provide a reliable, transparent, and virtually tamper-proof solution.
But how exactly does it work? What does “legal timestamp” really mean? And how can you take advantage of this technology through platforms like Contractualis without getting tangled up in cryptocurrencies or smart contracts?
Let’s break it down step by step, with no unnecessary technical jargon.
What is “integrity and legal timestamp” in a contract?
Before diving into the world of blockchain, let’s clarify the legal concepts:
- Integrity: This means the content of the contract hasn’t been modified since it was signed. The file remains exactly the same—no changes or alterations.
- Legal Timestamp (or “fecha cierta”): This refers to the ability to prove with certainty when a document existed. Under Mexican law, this is essential to validate that a contract already existed on a specific date (e.g., before a lawsuit, audit, or legal dispute).
Traditionally, this has been achieved through:
- Notarization by a public notary
- Timestamping by authorized entities
- Physical delivery with acknowledgment of receipt
However, all of these methods are costly, poorly automated, and often depend on inaccessible third parties.
This is where blockchain comes in 🚀
In simple terms, blockchain is a public, decentralized, and immutable database. All information stored on it is permanently recorded and distributed across thousands of computers around the world.
When using a platform like Contractualis, you don’t need to be a cryptography expert or write smart contracts. The process works like this:
- A hash of the signed contract is generated.
A hash is a unique digital fingerprint of the document—an alphanumeric code that would change even if you edited just a comma. This fingerprint doesn’t reveal the content of the file, so your information remains private. - The hash is registered on the blockchain.
This creates public, tamper-proof evidence that the document existed exactly as it was at a specific time. That timestamp is what we call the legal timestamp. - It can be verified at any time.
Anyone (a judge, company, auditor) can check the blockchain to confirm that the hash was registered on that date. If the original file produces the same hash, its integrity is verified.
Benefits of using blockchain for contracts
✅ Strong technical evidence
A blockchain hash is highly reliable forensic evidence. It proves that a specific file existed on a particular date and hasn’t been altered.
✅ No dependence on third parties
No need for notaries, physical seals, or costly certifications. Blockchain is available 24/7, with no bureaucracy.
✅ Saves time and money
Registering a contract on the blockchain costs just a fraction of a notary’s fee and can be done in seconds from any device.
✅ Transparency without compromising privacy
The actual contract is not stored—only its digital fingerprint. Your document remains confidential while its existence is publicly verifiable.
Is this legal in Mexico?
Yes. The Mexican Commercial Code, in Article 89, recognizes data messages and electronic signatures as valid, provided they can be attributed to a person and their content has not been altered.
Additionally, the Law of Advanced Electronic Signature (LFEA) supports the use of technological tools that ensure authenticity and integrity.
And here’s the most interesting part: civil and commercial courts in Mexico have already accepted blockchain as valid evidence to prove legal timestamp and document integrity.
That said, everything depends on how the technology is implemented. It’s not enough to just say “I uploaded it to blockchain”—it has to be done in a technically verifiable way.
How does Contractualis implement it?
At Contractualis, we use blockchain as a transparent backup for every document signed on the platform.
This means that when you upload a contract, add signers, and complete the signature process:
- We generate a SHA-256 hash of the file.
- We register it on a public blockchain (such as Bitcoin or Ethereum).
- We issue a certificate of integrity and legal timestamp, with a public link to validate it.
The entire process is automatic, with no hassle for you or the signers.
Why is it better than other solutions?
Some platforms only store the contracts internally and don’t use blockchain. That doesn’t truly guarantee integrity or legal timestamp.
Others do use blockchain but require wallets, cryptocurrencies, or technical know-how.
Contractualis makes it simple: you focus on signing, we take care of the tech and legal backbone.
Real-world cases where integrity and legal timestamp save the day
- Labor lawsuits: A digitally signed contract registered on the blockchain serves as strong evidence that an employee accepted certain conditions on an exact date.
- Tax audits: If the SAT or another entity requests proof of when an agreement was signed with a supplier, the blockchain certificate may be the most reliable evidence.
- Fraud prevention: If someone tries to alter a contract after it’s been signed, the hash won’t match anymore, and the tampering will be obvious.
Hassle-free digital trust
The integrity and legal timestamp of a contract are no longer exclusive to physical or notarized formats. Thanks to blockchain, you can now have legal and technical protection with a single click—right from your phone or computer.
If you’re still sending scanned PDFs or contracts by email without protection, it’s time to level up.
Contractualis gives you that extra layer of security without requiring tech expertise. And best of all: if you ever need to prove that a contract was signed, you won’t have to cross your fingers… you’ll have solid legal and technical proof.
Ready to protect your contracts?
Try Contractualis for free and start signing with digital confidence.
✅ Easy, fast, and backed by blockchain.
