Development a Blockchain network to save pdf files instead of transactions.

[electrobit]

Hi guys, I am starting to develop and to write code for Smart Contracts and Blockchain networks. I have seen this very amazing. The project or the idea I´ll share you all now is about Blockchain, I would like programmers and developers to help me with ideas or commenting exactly how they´d do it.

What I am doing now it´s a Blockchain network and its purpose is to secure pdf files in order to give transparence and trust to everyone who´s going to use those documents. For example...

I have "n" documents or files in pdf format, I will upload them in a website but I want to protected or secure them with a Blockchain where they are going to be saved, of course those blocks of the chain should have a hash. When somebody wants to download them, they won´t need to think whether those are fake or real because the can prove them looking at the Blockchain network as Bitcoin network...

If everything from above seems confused, just you can participate commenting how would you relate the Blockchain technology with pdf files, in order to give transparence and trust to the people who´s goind to download it to verify any thing...

Thank you everyone who wants to help in this project and wants to participate commenting, it´s something very challenging (at least for me that I´m starting to develop in these topics).

PSDT: I am using Go language to program Blockchain networks.

Regards!!!
electrobit   

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[NeuroticFish]

I have "n" documents or files in pdf format, I will upload them in a website but I want to protected or secure them with a Blockchain where they are going to be saved, of course those blocks of the chain should have a hash. When somebody wants to download them, they won´t need to think whether those are fake or real because the can prove them looking at the Blockchain network as Bitcoin network...

1. Who will store (and mine) your blockchain? Or better: what incentives you have in mind for 3rd party to store and mine your blockchain?
2. Is it only you who "uploads" pdfs? Who certifies those pdfs are the "real" ones? Also, most pdfs are worthless, you actually plan to build a platform for certain institutions to store their documents?
3. Let's say somebody wants a pdf. OK. He gets the link, he verifies the checksum. It's legit. But he wanted the pdf with the engine of a rocket and he got the pdf with a novel. The checksum is correct for the pdf, but it's not the expected pdf. What now? How you solve this?

I still don't understand the usefulness and the meaning of this... but from your (vague) explanation it sounds like it may need quite a lot more thinking.

[electrobit]

Thank you for answering. Well..:

1. Who will store (and mine) your blockchain? Or better: what incentives you have in mind for 3rd party to store and mine your blockchain?

This is a project where we are gonna try it with a group of programmers. This is focused to save some files from a company and we need a blockchain to give more transparence. I repeat it again, it´s like a try and of course the firsts documents will be normal, after we can be thinking in to make it in a larger scale. Who are gonna to store and mine the blockchain will be the person interested in see and download those files. There are no incentives while mining, the purpose to share this project here is to find ideas about how to program the blockchain because we are talking about pdf files, not about transactions.

2. Is it only you who "uploads" pdfs? Who certifies those pdfs are the "real" ones? Also, most pdfs are worthless, you actually plan to build a platform for certain institutions to store their documents?

Not only me. Let´s suppose I am the only one who can because (example) I am an university and do not need someone else can upload, we just would need the blockchain to secure those documents.

3. Let's say somebody wants a pdf. OK. He gets the link, he verifies the checksum. It's legit. But he wanted the pdf with the engine of a rocket and he got the pdf with a novel. The checksum is correct for the pdf, but it's not the expected pdf. What now? How you solve this?

This is a few opposite, we want a blockchain system to avoid someone edit documents and upload incorrects pdf files. For example. Me who´s the university is gonna upload any file, the rest of the nodes proves that is correct the info I am uploading to the network. Another thing, we are making this in order to upload certificates, this means the pdf files gonna have just 1 or 2 pages, with this the rest of people (nodes) won´t take too long to verify any mistakes on them.

I still don't understand the usefulness and the meaning of this... but from your (vague) explanation it sounds like it may need quite a lot more thinking.

That´s the reason why I am posting this topic here. To find others thoughts and ideas with you all and with programmers.

[madu]

Hello electrobit,
storing verification data in a public blockchain is in general good use case of blockchain. However, I know at least one project which has the exact same aim (saving pdf-files and certificates in blockchain). I forgot the name, but Google will surely have the answer.
When they explained their model, I had the feeling they used "blockchain" only as a marketing buzzword. Especially in these use-cases of blockchain, you have to think about centralization. Has there to be a trusted party? If yes, why should it be trusted and where is the benefit of using a blockchain instead of a centralized database?
When the team explained their reason for using blockchain I was not convinced. I did not see any advantages of their approach compared to digital signatures or the usage of a centralized database.

If this should not be a "just-4-fun"-project, you honestly have to discuss the following questions:
(Don't answer them here.. otherwise its going to be an endless discussion. Just be sure you have an answer to each question which you honestly believe)

1) Why does the whole pdf need to be stored in the blockchain? Wouldn't it be enough to save the signature of the pdf in the blockchain?
2) What are the advantages of your approach compared to digital signatures for pdfs (check adobe)?
3) If it's about storing documents in a decentralized fashion - What is the benefit compared to storj, filecoin, sia?
3) Should it be a standalone blockchain, forked chain or subchain?
4) Should it be an open blockchain, federated or private blockchain?
3.1) If it should be an open blockchain: - Who are the miners/nodes? What is their benefit?
3.2) If it should be a federated/private blockchain: - What's the benefit of using a blockchain in your use case compared to a centralized (open) database?

[electrobit]

madu You gave me many ideas with your comment... Thank you (merit) so much for openning my eyes guy! Regards...

electrobit

[ABCbits]

1. Have you looked on similar project such as IPFS? You could combine/build your blockchain network on top of IPFS just like what Filecoin did
2. Assuming you're using public permissionless blockchain model, have you thought any ways to prevent majority attack or make it really difficult?
3. Allowing PDF files uploaded together with PGP signature for it could improve trust/security problem assuming users who want to download PDF files already have valid public PGP key for verification

The thing about documents is they aren't verified the way bitcoin transactions are. For a transaction to be accepted by peers, it just needs to have a valid set of inputs and outputs with enough coins to spend. A blockchain for PDF files can verify that a PDF was uploaded, but there is no way a node can verify the content of the PDF, and whether or not it is legitimate. That requires human intervention, and at this point, you might as well not use a blockchain at all. I don't see how the two work together.

There are few things you can check/verify such as :
1. Verify it it's actual PDF file or only uses .pdf extension
2. Check PDF file is corrupted or not
3. Check PDF version
4. Check if Steganography is used to hide message/file

[NeuroticFish]

I understood somewhat more. I guess that the system is more related to making sure only the correct people (owner) puts changes/annotations to a document, not necessarily about pdf (and actually there are more suitable document types for this).

Who are gonna to store and mine the blockchain will be the person interested in see and download those files. There are no incentives while mining

If you go by this model you'll be an easy target for anyone wants to do a 51% attack and put into the blockchain any bad files / changes / checksums he wants.
You need something better (safer) than this.