

Show HN: Stampd.io - A document blockchain stamping service - altereg0
http://stampd.io

======
logn

      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.

~~~
snuxoll
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.

~~~
logn
> 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.

~~~
abacus76
you could prove that you certified the document by including your name and or
signature within the document!

------
telecuda
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?

~~~
abacus76
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.

~~~
telecuda
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.

------
DenisM
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!

~~~
snuxoll
> \- 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.

~~~
altereg0
That is correct. Nevertheless it may also be convenient for someone to sign
the document after dragging it in the stampd box.

------
altereg0
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.

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

~~~
abacus76
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.

------
leni536
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.

~~~
abacus76
Could you indicate how much more expensive?

------
nadaviv
Related:
[https://news.ycombinator.com/item?id=5790382](https://news.ycombinator.com/item?id=5790382)

~~~
abacus76
indeed this is one more excellent application of the whole idea. One
difference we have is that we are using the OP_RETURN though.

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

~~~
abacus76
Thanks.. The hash is the SHA256 of the document which is a standard procedure.

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

~~~
mynameisvlad
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).

~~~
abacus76
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.

------
bjackman
You should also have an app for quickly verifying stamps.

~~~
abacus76
Actually if you try to stamp the same document it directs you to the
appropriate verification

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callesgg
Cool idea, very expensive.

~~~
abacus76
We decided to reduce to 0.99 euro from 1.49 euro. This should be small enough
to be considered as a fair price.

