Show HN: Stampd.io - A document blockchain stamping service | Hacker News Reader

Show HN: Stampd.io - A document blockchain stamping service

stampd.io

32 pointsaltereg035 comments

  Your document titled: hello world is about to be stampd on the blockchain.

  Please proceed with payment of EUR 1.49 through Paypal by clicking on the button below.

  After payment and the appropriate blockchain transaction transmittal, a PDF
  certificate will be sent to your email address as registered in Paypal.

It would be nice to support payment with bitcoin. Also in addition to emailing a receipt, let users download a receipt right there.

Also I'm not sure what exactly a webapp is needed for. I wouldn't use it for anything important. How do I know without looking through your client side JS that you're not sending a copy somewhere? It would be nice to write an open source app, stamp that app's hash in the block chain, and then use that stamped app to stamp other documents, all locally. Or keep the web version too as an alternative. If you want to make money off of that, provide some enterprisey tools for people to verify previously stamped documents or other value-add services not related to the core offering. I think you're losing 99% of early adopters with a fee (is that essential to pay miners or something?).

edit: It seems like I'd need a way to verify my identity as part of this hash for it to be of value. Can your certificates be forged? A verifiable and un-forgeable certificate would be valuable. Or perhaps I associate a BTC wallet id with a small amount of money in it and that's part of the overall document hash too. So when I want to prove I hashed it, I send a tiny fraction of a bitcoin from that wallet (and it could be an unpredictable fraction, to serve as a one time PIN). Making all that easy to verify for someone like an underwriter or lawyer could be a nice way for you to make money.

You aren't worried about the certificate itself being forged, all it contains is details on the block that the document was signed on and the hash of the document, you can't forge this since you still have to make a SHA256 hash of the document and verify it against the blockchain. The whole point of this transaction is the blockchain itself records the time that a specific block was mined, if the hash of the document was in that block then that means the document did in fact exist at the time.

> then that means the document did in fact exist at the time

I was thinking of a way to prove too that I certified that document, to tie it back to my identity.

you could prove that you certified the document by including your name and or signature within the document!

We do plan to support a stamp payment in bitcoin (of course!).

The certificate is issued only after 2 blockchain confirmations (that is why we email it later because this takes about 15 to 30 mins). It is also available on line on stampd after that!

From our perspective a fee is essential both for the transaction miner fees but also to prevent blockchain bloating.

Regarding the certificate forging: Our certificate only refers to what the blockchain shows. We decided to issue such certificate in order to allow the user to easily refer to the stamping. It is the blockchain that cannot be forged!

Your suggestions are all very interesting and we are grateful for sharing. We will certainly explore them further. We are fascinated by the potentials of blockchain's public ledger and of course these and many more ideas could have outstanding applications.

Just paid to stamp a document and thought the process was very easy - nice job!

Question: Help me understand the bitcoin financial transaction - I'm not well-versed in bitcoin. In blockchain.info I see "Total Input: 0.0002 BTC" and "Fees: 0.0002 BTC". Is my assumption correct that you had to make a minimal legitimate bitcoin transaction to appear in the ledger (.0002BTC / $0.05), then pay that same amount again as a fee, costing you roughly $0.10USD?

More simply, how much bitcoin is being transacted and who is it going to/from in order for you to create the stamp?

Thanks! Actually the transaction creates a zero unspent output (thus no transfer of sum is being carried out). Still we allow for 0.0002BTC for miner fees (which go to the miner's wallet). Miner fees plus paypal fees is the total cost for us per stamping. Of course there is also a cost for the server etc.

Thanks. Not questioning the cost of your service - that's for you and the market to decide! Just trying to get a better understanding of how the bitcoin transaction works.

Excellent idea!

- I'm not sure about E1.50 price, I think $0.99 would be easier to swallow, psychologically. I understand you have the transaction cost weighing on you, so maybe sell packs of 5 signatures for $4.95? This also gives you ability to run promotions with discounted signature packs.

- Alternatively a monthly subscription could be interesting as well. Imagine if I'm writing a novel, I might want to keep signing different copies as I go along many times per day, but then rewrite them anyway as I'm not yet satisfied. It would be nice if you shipped a simple text editor that saves all local copies of the work as it's modified, together with persons's name and your timestamp / signature, as a proof of concept. You could be delaying or batching transactions to offset the bitcoin tx cost.

- I liked the easy drag and drop for a picture, but sadly I have to put my signature into the picture which takes away all of the drag-drop convenience. It would be more convenient if it worked by me drag-dropping the picture and then typing in free-form text into your web site, such as "Copyright (c) DenisM aka foo@bar.com", and then you hashing (picture + signature), detailing the procedure in the PDF.

- In a weird way contradicting the convenience aspect I just asked for, I would prefer to give you my hash of the document rather than document itself. I may be afraid of the content leaking before I am ready to release it myself. It's an easy fix for you - add a separate tab where instead of dropping the document I can paste in the hash myself.

Keep up the good work!

> - I liked the easy drag and drop for a picture, but sadly I have to put my signature into the picture which takes away all of the drag-drop convenience. It would be more convenient if it worked by me drag-dropping the picture and then typing in free-form text into your web site, such as "Copyright (c) DenisM aka foo@bar.com", and then you hashing (picture + signature), detailing the procedure in the PDF.

EXIF metadata is embedded in images and would be calculated in the SHA256 hash. Just add an EXIF tag including your copyright and you're done.

That is correct. Nevertheless it may also be convenient for someone to sign the document after dragging it in the stampd box.

Thanks for your kind words, your valuable comments and very interesting suggestions! Will consider...

One more thing.

Consider publishing all you hashes for each day in a digest to e.g. USENET or other permanent public storage, then hashing all of those daily hashes together and publishing the meta-hash in New York Times. That way even if blockchain fails as a dating method due to forgery, one could use USENET + paper copies of NYT to date any of the documents. As a matter of fact, there is no limit to how many different ways of dating a hash you could add to your service.

Just make sure you're also including a previous day's unpredictable event (stock market activity?), so that both early and late boundaries can be established with confidence.

This would mean that one would eventually have to rely on the NYT which is a "centralized" source of information. According to the bitcoin experts the blockchain cannot be forged, especially if one's transaction is older than a few hours. If the bitcoin community are right about the above and if you think of the blockchain as a non-centrally-relied bulletin that anyone can write anything (as long as they pay the appropriate fees to the bitcoin miners) and that nobody can erase what was written in the past then there should be no need for relying on any other source of information such as the NYT. On the other hand your idea could be useful as a backup, in case something goes wrong in the blockchain technology!

Backup is exactly what I suggested. Don't rely on a single technology, especially if it's crypto.

stampd.io is a web application which helps you apply a blockchain stamp on your art or creative content in general. I would be very happy to hear your comments, suggestions or any questions if you have the time to spare a look. A blockchain stamp can allow you to certify the existence of your content at a specific point in time. If your content is original it can also allow you to prove unquestionable ownership without having to rely on any third party service or authority. We are confident that this new technology can revolutionize the intellectual property rights of creative content.

The time stamping used in stampd's process is carried out in a way through which the user is able to undeniably prove the stamping in the future without relying in our service (or to anyone else's).

Any user of stampd, just by having in hand:

(a) his electronic file (the one with the original content and his signature) (b) the PDF certificate that we issue after stamping which explains all the technical details of the stamping on the blockchain.

...may prove his stamping to anyone needed in the future, simply by using the above and any of the available blockchain explorers.

We would be glad to hear your impressions or any suggestions you might have.

Is there any legal precedent that a court will accept this stamp as evidence of ownership?

As far as we know there is no legal precedent, nevertheless any IT expert wittness should be able to verify in front of a court that as things stand right now it is impossible to forge the blockchain time stamp.

> its certification is carried out by posting the document's cryptographic imprint (hash) on bitcoin's blockchain.

> Pay with Paypal

I, too, am curious about the need to pay via PayPal for a bitcoin-driven product. A conscious decision for a specific reason?

Some FOSS projects should stamp their git master commit hash regularly to protect their ideas against future patents with proving prior art. CAs' timestamping services are far more expensive.

Could you indicate how much more expensive?

indeed this is one more excellent application of the whole idea. One difference we have is that we are using the OP_RETURN though.

This is pretty cool. Though, I'm confused as to how can you prove that the hash decrypts to you document?

Thanks.. The hash is the SHA256 of the document which is a standard procedure.

How do you prevent people from submitting content they don't own?

The service doesn't seem to give proof of ownership, just proof of existence at a particular point in time (ie. This document was submitted and verified at 12:13PM PST on 2/18/2015, so it must have existed at that point in time).

Ownership of content could be supported in the sense that you publicly annouce its creation first (blockchain is public) with no other previous record of it anywhere. Of course if the content is not original work then it should be traceable in the past thus it would be completely pointless to stamp it on the blockchain.

actually you can't. But there is nothing to gain in doing so. This seem to work only if the content is original work

You should also have an app for quickly verifying stamps.

Actually if you try to stamp the same document it directs you to the appropriate verification

Cool idea, very expensive.

Thanks! What would be a price you could consider as fair?

We decided to reduce to 0.99 euro from 1.49 euro. This should be small enough to be considered as a fair price.

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