All you need to know about digital file notarization via blockchain.

Getting Started

Notarization helps to prove that a document is authentic and unchanged since it was created.

To achieve that we enable you to upload files to the blockchain as a hash value (if your file is private) or as digital copies of your files (if the files are public).

For private files, the method is called file hashing (aka file verification) and the hash value is something like bcd64e87ebc221342ebbd3ed434d31d8ba6198b89615e577fcf9a539f1c9ef1f.

This gibberish string is unique only to the file you uploaded. If you edit even a single character in your original document, the hash value will change significantly.

This way we can attest to your original file and that it has not been tampered with. 

Since data on the blockchain cannot be deleted or altered, this could proves the date and time your file existed.

For public files, since the digital copies stored on the blockchain cannot be deleted, we can prove its existence on the chain at a point in time.

Files are stored on the blockchain as NFTs (non-fungible tokens). What part of the file is stored in the token depends on if the file is public (can be seen by everyone) or private (only can be seen by you).

Public file –  The entire digital copy of your file is stored inside the NFT file token via decentralized IPFS storage. This means anyone who views the NFT can read the file.

Private file – Only the file hash is stored in the NFT token. People can only view the hash string (e.g 49363dafae6c1760d1d3a949f9…) only.


We use the best and most commonly used hash algorithm which is SHA-256 (also known as SHA-2). It is considered more advanced than other algorithms such as MD5 and SHA-128.

In fact, this encryption algorithm is commonly used by cyber security and forensic experts and even your local bank.

SHA-256 algorithm is superior because it is collision-resistant. This means it’s impossible to have two different files hashed with SHA-256 that would result in a similar hash value.  

No. Regardless if you generated the hash value of your file on Windows, MacOS, Linux, or even iOS and Android, the hash value created will be the same.

It’s free because we do not charge you a single cent to use our system.

However, you need to pay for gas fee (usage fee) when you interact with the blockchain to notarize your file.

To pay for the blockchain fee, you need to load your wallet with the specific tokens for the specific blockchain. 

For example, for Ethereum blockchain, you need to have ETH tokens. For Polygon chain, you need to purchase MATIC tokens. For XDC network, you need to XDC tokens. 

But you can get free tokens from us. So, it’s actually 100% free!

Yes, absolutely. We only helping you to pay for the gas fee and we do not own your files or your smart contract. 

Think of our free tokens like a free gift to help you use our service. 

A public file is visible to everyone where the file content, name, and description are uploaded to the blockchain and decentralized storage (IPFS). It is also listed and searchable on our site.

A private file, however, is only visible to you and only the file hash is recorded in the blockchain without name or description. It is not searchable or listed on our site.

You may read more about it here and here. The good thing is that our site works in harmony with blockchain to strengthen your case in the eyes of the law if you ever choose to admit your file in court.

Your file and hash are stored on our website as well as on the blockchain. This offers a complete audit trail where we can verify that you, the owner of your wallet, actually uploaded your specific file on what date and time on the blockchain.

Traditional notary service aims to provide offline services that cannot be provided the online way.

Some of the offline notarization services are,

Acknowledgment – Acknowledging a person signed a document. Similar to being a witness.

Jurat – Compels a signer to swear that the contents of a document are true. Signing must be done in front of the official.

Oath or affirmation – Compels a person to be truthful.

Signature witnessing – The signer must sign a document in front of the notary.

Copy certification – To certify that a copy of a specific document is true, exact and accurate to the original.

Our online notarization covers the purpose of proofing that a document exist at a point in time and that the document is not tampered with.

Our online service is also cheaper than traditional notarization service and is more convenient to use since everything is done online. 

Traditional notaries may extend their offline services to their customer by offering an option to include blockchain notarization.

We don’t aim to replace traditional notarization services as we aim to complement them.

A notary could offer our service as an addon to their existing service. This way, they can offer physical and digital services as one.

You may select between public or private file before uploading.

Private file remains strictly private to you only. This means the digital file itself is not stored on the blockchain but only the file hash string. Anyone who has access to the blockchain cannot read your file and the file is also not searchable on our site.

If you choose to upload a public file, the file is visible and downloadable by anyone who has access to the blockchain. The file is also searchable on our site.

You may generate the hash value for your file at other sites such as this.

Then, you may compare the hash string generated by our system and the other site and you’ll realize that the string value is the same.  

You may upload more than one file each time. This means you may store more than one file in a single blockchain NFT token. We currently set a maximum number of files and it is specified prior to uploading. 

Your file will still live in the blockchain. And you may still access them via the blockchain block explorer.

The maximum file size is set to 10MB. This means each file cannot exceed this limit. But you may upload a few files of up to 10MB each.

Please ensure you have stable Internet connection when uploading a large file.

Your files kept on the decentralized data storage system called IPFS should be there permanently within your lifetime and beyond.

For the blockchains, we foresee the networks will last very far into the future.

You may upload any files as listed below.

  • Documents (pdf, docx, docx, xls, xlsx, ppt, pptx, txt, hwp, html)
  • Images (webp, jpg, png, gif, tiff, bmp)
  • Compressed files (zip, tar, rar)
  • Essentially all the files listed here, except application files.

You are not allowed to upload application files at this moment.

This is virtually impossible for public blockchain. This is because of the decentralized nature of public blockchain where each node (a server) must syncs its clock with other nodes. You may read more about how clock synchronization works on blockchain.

Fees and Cost

We do not charge any fee to use our system. However, the blockchain that you select to use may charge a gas fee. This fee is paid usually with their native tokens (cryptocurrency).

But the good news is that we are offering free tokens for you to use our service. 

Different blockchains charge differently as their tokens’ price depends on the market value.

For Ethereum chain, the estimated total cost can be more than $50. But if you use other chains like XDC or Polygon, the cost is less than $0.01.  It actually costs less than 1 cent to deploy your smart contract and upload your file on the blockchain.

Think of gas fee as the usage fee to use a blockchain. The price depends on which blockchain you decide to use to notarize their document. 

For example, Ethereum blockchain is notoriously for charging high gas fees to users because their current platform is overcrowded with users and suffer from a non-scalable system.

Other chains are much cheaper in gas fees.

Blockchain and Smart Contrat

Think of smart contracts as apps that sit on a blockchain network, just like your mobile apps on Android or iOS operating system.

It’s essentially a software program to run operations on the blockchain. In order to notarize your files on a blockchain, you need a smart contract to facilitate this. The smart contract’s purpose is to create the NFT token that contains your file’s information such as URL or hash value. Think of this NFT token as a JSON or XML file or simply a text file containing data related to the file you notarized.

Our online service helps you create your own smart contract that will process and upload your files on the chain.

Currently, you can only create one smart contract for one wallet. This means you may have one contract tied to one wallet only.

But you can have multiple wallets owning multiple contracts on a single blockchain.

In the future, you may create more than one smart contract for a wallet.

Gas fee is the usage fee that is charged by the blockchain not us. Since blockchain is a decentralized network (unlike network of Google services) someone has to be paid to run the network. It is the job of that someone to store your data on the chain.

Thus, their compensation is the gas fee paid in cryptocurrency tokens. For example, for Bitcoin chain uses Bitcoin (BTC) tokens for payment and Ethereum uses ETH (Ether).

We currently support multiple blockchains and mainly EVM-compatible (Ethereum Virtual Machine) chains. Please check our main page for the list of chains we support.

No, you own the smart contract because you need to deploy your own smart contract on our site prior to uploading any file to the blockchain.

We support any EVM-compatible blockchain network (those that are compatible with Ethereum). But you need to have some tokens for your preferred network prior to deploying.

You can have as many smart  contracts as you wish but each contract is linked to only one wallet only.

We support MetaMask and other wallets that works with WalletConnect.

You own all the NFT tokens that you created because you own the smart contract that issued the tokens. We do not own nor store any copies of your tokens. In fact, it’s technically impossible for us to do that.

You may view our smart contract code at our GitHub repository

We are using mainly OpenZeppelin library.

This is virtually impossible for public blockchain. This is because of the decentralized nature of public blockchain where each node (a server) must syncs its clock with other nodes. You may read more about how clock synchronization works on blockchain.

No. You may check our smart contract code to have the peace of mind knowing that our smart contract is not programmed to conduct any malicious actions.

The code is a very common program used to create NFT tokens. 

The answer is no. Because your files were uploaded on the blockchain using our smart contract and this software program does not contain a command to delete your files. You may view the source code of the smart contract here

This means your files will be stored on the blockchain that you used indefinitely.