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Proof of existence On Blockchain - The Complete Guide
Crypto Basics For Beginners

Proof of existence On Blockchain - The Complete Guide

By Oreld Hadilberg
Reviewed by Tony Spilotro

Table of Contents

Blockchain technology can perform many functions. Technology has found its way into diverse sectors of human existence. Being a public and immutable ledger, many things can be recorded and stored on the blockchain for years without tampering.

For instance, businesses can store transaction data on it without fear that another party will manipulate it. But before storing any data, some designated group of people must verify that it is correct. For instance, the most popular use of blockchain technology is cryptocurrency.

Crypto transaction records are stored on the blockchain in the form of blocks. But before creating the block, the data must be verified through a proof of work, proof of stake consensus mechanism, and others. These processes are the popular ways of verifying transactions on the blockchain.

But then, there’s another way of storing and verifying data on the blockchain; proof of existence (PoE). In this case, users don’t verify business transactions but existence proofs of documents. We already know the PoW mechanism uses mining while PoS uses a staking process. But what does PoE mean, and how does it work?

Find all the answers below. We’ll also explore the use cases of this data validation mechanism and why it is necessary for document existence.

What Does Proof Of Existence Mean?

Proof of existence is a mechanism that enables the owner of certain property (intellectual) to record its existence and later prove it. The property might be a media, document, or file. Once the owner stores it on the blockchain, the property is permanently validated and timestamped to show the time and date of the action.

Afterward, he can produce the timestamp and digital signature associated with the document as proof of existence. With that, he can prove that the object exists.

Digital signatures on the blockchain are impossible to forge. It relies on public key cryptography, which encrypts and secures sensitive information. Normally, in crypto, a user has a public and private key.

Everyone on a blockchain sees your public key but can't know your private key. You only input the private key to verify that you’re the one making a transaction.

In the case of PoE, you will use your private key in the signature algorithm to link your property and your public key. Once someone sees your public key, they’ll know the property was signed with your private key and therefore is yours.


Timestamping proves that the owner of a file, document, or information held it at a specific time, which can't be forged. A document is stored online anonymously to aid the proof of existence process. The owner will store the cryptographic digest of his file linked to when he submitted it.

The online service will timestamp the hash of such documents. For instance, once a user timestamps a document or intellectual property on the bitcoin network, it becomes impossible to be tampered with by anybody. The timestamps are stored worldwide through the mechanisms of the network.

Traditionally, trusted timestamping services are rendered by third parties known as TSAs (Time Stamping Authority). Unfortunately, these solutions can be compromised, leading to data leaks and corruption. That’s why it’s safer to utilize the blockchain.

Why Pursue PoE

Proof of existence is necessary for the public sector. It helps governments and agencies reduce disputes over intellectual property ownership rights. All the owner has to do is show the PoE to the authority and verify his claims.

Proof of existence will also help individuals to protect their ideas. You don’t have to lose that lucrative invention that could change your life. You can store it permanently on the blockchain and show proof later.

Also, proof of existence is necessary for a time when cybersecurity needs have increased. The mechanism will enable blockchain users to resolve matters through an automated system without a centralized authority.

Use case of PoE on the Blockchain

Some of the use cases of proof of existence include,

  • Checking the integrity of a document
  • Proving the ownership of a data, file, media, or other intellectual properties without disclosing the contents
  • Proving a deed transfer
  • Time stamping on documents.

But note, storing and reuploading a document on the blockchain works perfectly if there haven't been changes or alterations. If someone else changes a record and tries to reupload it, the system will flag it as different. By that, the rightful owner’s interest is secured.

Why Store intellectual properties on the blockchain

Storing intellectual properties on the blockchain is important to reduce the cases of fake document presentations. Many people fake every document, from birth certificates, health records, sale deeds, and death certificates to tax returns. Sometimes people even forge education certificates and employee service records.

But all that will stop if organizations that use these documents mandate owners to store them on the blockchain and only present their Proof of existence. Being a distributed public ledger, the blockchain can be accessed anywhere. Also, once anything is stored on the blockchain, it becomes unchangeable. That's why words like "Immutable" have been used to describe it.

Since the blockchain flags tampering, only the owner of a stored file or document can access it. Once the owner provides the unique identifier, which might be a transaction ID or a cryptographic hash, the receiving authority can verify that he owns it.

Why Use Bitcoin network

Even though the TSAs can timestamp documents, they're safer to be stored on the blockchain. But why use the bitcoin network?

  • Anonymity

Transactions on the Bitcoin network are completely anonymous. No one knows the initiators directly. Other users can only see your address and not the person behind it. Moreover, every timestamping activity on the network remains hidden from others. There’s no way to identify those doing it.

  • Affordable

Timestamping documents on the bitcoin network is cheap. You can spend just 5 cents or lower sometimes in the process. Other times, you can even do it without paying anything. Although it's advisable to pay the small fees supporting the miners who use their computing resources to verify such transactions on the network.

  • Decentralized proof of existence

One reason to timestamp documents on the Bitcoin blockchain is to get a ready proof of existence for future reference. Once you store the record and it's validated, it becomes yours permanently, and no one can manipulate it. Also, even when the site you used is down, you can access it through another node. The best part is that no central authority has power over your document.

  • Dispute resolution

Timestamping documents or information on the bitcoin blockchain helps entrepreneurs avoid disputes. By protecting their data before sharing it with others, they will hold the proof of existence that no one else can change since the file is on the blockchain.

A Notable Use Case For Proof Of Existence

The proof of existence mechanism verifies intellectual properties. It can also be used for verifying other ownerships. Let’s check one of the salient use cases below.

Registration of land ownership in Georgia

Georgia was one of the first places where proof of existence came into play. The reason was to avoid data manipulation and leaks and eliminate the centralized control system.

According to history, the government incorporated the mechanism into its operations to store the hashes of citizens' land registry documents on the bitcoin blockchain.

Bitcoin network is decentralized and operates based on a peer-to-peer architecture. That’s why they used it to store the hash number of each document. The numbers were the identifiers or existence proofs of each document.

Once the citizens present the identifier to any receiving authority, they’re usually accepted as legit and valid. Since the blockchain is immutable, it was clear that no one can edit anything stored on it.

Moreover, even if the servers of the government agency crash, citizens can always use the hash number to access their documents from anywhere.

Practical Examples Showing The Need For Proof Of Existence In Real World Applications.

There are so many real-world scenarios where proof of existence applications could help save the day. Let’s discuss some of them below.

1. Loss of documents in Haiti

This is one of the real-world incidents where the application of proof of existence could have helped to mitigate losses. Haiti experienced a terrible earthquake in 2010. The earthquake destroyed many government buildings and servers where citizens' documents were stored.

As a result, many land registry documents were deleted, causing a lot of land ownership disputes. It was hell for the citizens and the government because they failed to provide proof of existence for those documents.

But the disputes would have been avoided if the government had adopted the proof of existence mechanism earlier. The documents would have been stored on blockchain technology, and hash numbers were given to the owners.

All the citizens would have done is to provide the PoE for the officials to access the documents and verify their time of record and ownership.

2. Education certificate fraud in Northampton

In 2017, a woman forged certificates for two teaching jobs in Devon and Northampton. She also used the forged certificates for a role to mark A-level papers for an exam board. Before this role, she had already used the same fake certificates to teach in a university and even obtained a PGCE qualification.

Her dubious certificates were later discovered when she applied to teach in Torquay. In the course of verifying the authenticity of the certificates, the school reached out to the awarding universities and discovered the deceit. She was tried and sentenced to 18 months in prison.

This incident would have been discovered earlier if the organizations that award these certificates recorded them on the blockchain. The receiving bodies would have simply used the unique identifier for the certificates to prove their existence and verify ownership.

3. Medical certificate fraud in London

A man posing as a doctor duped thousands of pounds from people in London. The scammer claimed to have a medical degree from Cambridge University and was even the head of a research team at a London University College Hospital.

The fake doctor also lied about treating Robbie Williams, the Queen of London, and Lord Sugar. He even diagnosed a patient with cancer using fake qualifications.

Fortunately, the man was caught and charged in court, receiving a four-year sentence. But in court, he kept insisting that the Official Secret Act prohibits him from discussing his treatments. Such incidents would have been stopped earlier if there was a way to prove he was not a certified doctor.

4. Intellectual property thefts

There have been many cases of intellectual property thefts pre-blockchain era. Some of the cases would have been easily avoided if there was a way to store the ownership of such intellectual properties.

A more recent case that occurred in 2017 was due to a human error. An engineer working for Apple brought his daughter to work and compromised the company's intellectual properties. The daughter later shared a video containing the sensitive information online. As a result, Apple fired the engineer.

In a worst-case scenario, the act would have been deliberate, and the engineer might sell the details of the unreleased product to competitors. In such cases, Apple could only claim the rights to the property if it recorded the existence and ownership on the blockchain. The same scenario played out with a Microsoft product.

These incidents and more have necessitated blockchains such as Bloxberg, Certify dapp, and Signatura online services aimed at securing information.

Let’s explore them below.


Here is one of the first international blockchains aimed at securing scientific information. Bloxberg emerged to mitigate incidents of manipulations in science information. The blockchain emerged in 2019 and is fully decentralized.

Currently, Bloxberg comprises eleven leading research facilities in ten countries. According to scientists, it will change the management and communication of scientific data in the future. By storing scientific data on Bloxberg, users can easily authenticate them and protect their intellectual property rights.

Also, Bloxberg blockchain will facilitate other aspects such as peer reviewing, paper publications, and research results exchange without a centralized authority's interference. According to Sandra Vengadasalam of Digital Labs, the team pioneering the project, their members requested the technology. They had pushed for a timestamp or another way, such as a hash number, to certify the ownership of specific data before publishing them.

That was one of the reasons behind Bloxberg launch. But currently, the science data verification blockchain is using proof of authority PoA. This is an algorithm for a consensus mechanism that uses identity as a proof.

It allows a few designated users to validate interactions and update its registry. The reason behind PoA is to reduce the energy consumption of the process. The computational power is easy to manage, and the network scales easily since the validators are already selected.

Certify dapp

Here is another decentralized application on the blockchain for gene research data. Certify is built on Bloxberg and allows users to verify their files without sharing the contents. With this application, gene researchers can prove the existence of their data when the need arises.

Certify dapp allows end-users to track the proof of existence of their data on the blockchain. It records the SHA-256 hash and the timestamp for public records. By that, authorized users can view the records but can’t read the contents of the recorded file.


This is another solution that facilitates proof of existence in practice. Signatura can be regarded as a multi-signature receipt. This feature differentiates it from other digital signature providers. It enables many users to sign one document, a practice often required in legal and academic certificate authentications.

Signature use cases span many sectors, including banking, academia, government, educational institutions, and legal. The practitioners in these sectors can rely on the online service to sign different certificates on the blockchain.


The most popular use of the blockchain technology now is financial services. From the time Bitcoin emerged with the proof of existence feature, it has become clear that more satisfying solutions can be created on the blockchain.

By recording the existence of certain documents, files, and media on the blockchain, many cases of fraud, disputes, and thefts will be eliminated. All an individual or the government needs to do is ensure that such files are recorded, time-stamped, and secured with a unique hash number.

Once the need arises to present ownership proof, the owner can access and submit it to the reviewing authorities. One good thing about the blockchain is that data stored on it cannot be changed or stolen unless with authorization.

That’s why users are always advised to protect their private keys in the case of crypto transactions.