Bitcoin Forum

Site is temporarily offline due to fire in our offices.

Hey people,

We (jalaman and molecular) have earlier this year started to scan the casascius coins we sell, insert a hash of the image into the blockchain (as proof of age of the coin) and include a printed certificate wrapping up the information about the coin and proof. Looks like this:

https://i.imgur.com/EiKRpOwl.jpg (http://imgur.com/EiKRpOw.jpg)

People find these useful and I think they have the potential to increase the value of the coin in the future.

So I figured why not offer this as a service so people can "roll their own" certificates. So after quite a bit of work, here is a page that helps you do this:

http://certificates.0x0000.de

https://i.imgur.com/kwqIS15.png (http://certificates.0x0000.de)

The way it works is: you take photos or scans of your coin(s) and upload them. The site will combine 2 images (front and back of coin) into one and insert the hash into the blockchain (the tx id and stuff will be on the certificate), thereby making proof of age possible.

It will also produce a certificate you can download or have us print and send you.

It will also generate a text-file (list.txt) with all the relevant information to conduct the proof of age in the future.

You'll receive a file "bundle.zip" containing that text file, the certificates and of course (necessary to conduct the proof of age) the images of the coins. Looks like this:

https://i.imgur.com/Nzyvec5.png

Things might go wrong when you use the page. Don't worry, we'll fix it. Just record your session id (displayed on the main page) for reference.

Price is BTC 0.02 per certificate (including inserting the hash, of course).
For an additional BTC 0.01 we'll print the certificate and mail it to you

If you order any printed certificate we'll need your shipping address and also an email-address, otherwise the service can be used anonymously.

So, tell us what you think... we welcome any feedback.

Site is temporarily offline due to fire in our offices.

reserved

My friend actually used this service I believe pretty cool I will buy soon for my coins probably.

Cool! Let me know how it goes.

I think this is very cool development, will give you some feedback once I test it!

Sounds like a very interesting way to store info on the block chain. Looks great!

Maybe I'm missing something, but how do you get the hash into the blockchain? Just a text message on blockchain.info ?

Much simpler: I'm using the hash of the image as a bitcoin private key and sending a little bit of BTC (BTC 0.0001337 to be exact) to the corresponding bitcoin address.

So, the only way to verify the date, is reveal the private key? Simple enough, thanks.

It's not really stored on the blockchain, just a hash of it. But one can prove (using the info itself), that it has existed at the point in time where its hash was inserted into the blockchain.

This means one will have to safekeep the image itself (included in the download bundle.zip). Without it, you can't conduct the proof.

This seems really cool! I should try this out soon  :)

Thanks ;). Please do.

...Couldn't someone just look up the public address to see when the coin was first loaded?

I'm not sure why a separate proof-of-age would be needed.

And relying on a downloaded zip file to conduct the proof in the future sounds risky. Why not just have the hash be of some text printed on the card, naming the type of coin and its address? Then the card could be locked in a safe, and in 10 years when USB drives and all optical media is extinct people can still type it in to do the check  :D

That doesn't work because a counterfeit could have the same address printed on it as the original.


Again, someone could make "a copy of the coin", a counterfeit. You proof would be valid for that counterfeit also.

The idea with the image is that you can't counterfeit all the little scratches and imperfections that makes every coin an individual of sorts.

just added pricing info (0.02 BTC + 0.01 for printing & mail if you want) to OP.

I totally forgot that and you can't see it on the page until you upload photos.

I guess I'll have to fix the page too to display pricing.

Thanks to the guy who PMed me about this.

Does all that show up in the picture?
Does a brand new coin have any recognizable scratches??

It sounds more like a certificate of authenticity than anything.
I'm not playing devil's advocate here, just trying to understand the merits :)

That depends on the quality of the picture people upload. Here's an example of a simple 300dpi scan of 0.5 BTC coin (untouched by me, directly from a fresh roll I received from Mike): http://certificates.0x0000.de/img/1217gngJgcC2PiCGB7xscVZ1yFsNgyNVQH.tif. I'm pretty sure if you show me a coin and this picture that I can tell you with good certainty wether or not the picture is of the coin.


all the ones I ever scanned have discernable and many marks


What is a "certificate of authenticity" and what is it's significance? Who issues these? I'm not a coin collector, so if someone could explain how this works to me, I'd be happy. Sounds to me thats only something Mike could do and I think he will do something like this (sign with his pgp key scans of batches of coins). For old coins he can't do this, that's why he suggested to use "proof of age".

I'd say it's the proof of age that can be conducted that will potentially be valuable. The "certificate" I provide is just a nice addon you can appreciate or not.


Sure, no problem. I'm happy to explain my thoughts.

It is simply a certificate that says the object you hold is authentic, and not a fake or misrepresented.

The certificate can be issued by anyone who is knowledgeable enough to tell you if the item is real or not. And then the strength of the certificate would depend on who issues it.

I don't know why time is more important than proving it is an authentic coin, straight from Mike and not loaded by someone else. You know what year is on the coin, and you can see in the blockchain when the bitcoins were sent to that address. What else matters?

site is temporarily offline due to fire in our offices.

Whoever ordered a certificate and did not receive it, please PM me.

Are you back up yet? I am very interested in this service.

The problem is counterfeiting. How do you know that the coin you are buying is genuine, short of scratching off the hologram to check the private key?

Molecular's idea is excellent because it allows a photograph to be dated. If the coin being sold matches the photograph then you know that it was in existence at the date of the photograph. This does not establish authenticity, but the older the coin the less likely to have been counterfeited.