Topic: Casascius Coins - Series 2 (Read 2774 times)

I have updated it.

The price has mainly been rising, because the value of the BTC keeps falling.  I would love to sell them at a 0.3 markup, but given that that would give me 66 cents with current bitcoin prices, that would barely pay for my raw materials, and would leave me to work to create and package and ship the coins for free.  I can't afford to work for free...

The private key is on the back of the key paper, the window shows the front.  The private key length has been significantly expanded, in part, just in case some of the characters were somehow readable through the window.  It's now 30 characters.

Two questions:

Available on your site? I see "coming soon" and no price. I'm really waiting for the pricing information, I like the first series, but their price has been jumping between 0.2 and 0.85 (without content) -- I'd love it if the new ones will be 0.3 or lower when ordered in quantity.

Where is the private key written, does the window not reduce security? Haven't seen the old ones open yet, my last order is still underway.

I plan on getting some for xmas.  Want to give them to all the people I've been bugging about bitcoins for months.  That way they feel "included"

Looks really cool!! Can't wait for them to become available 

Mike, that's a great honest answer. Thanks. I totally agree with where you stand. Maybe add this information to your FAQ? https://www.casascius.com/faq.aspx

Formally?  I'm willing to formally guarantee that I have appropriately handled and destroyed all copies of the private keys because I can easily control that.  And that if you bought one from me, that I have sold you an honest coin.

Regarding the physical coins themselves?  I'd say informally at best, only to stay reasonable, since nothing is 100% unbreakable.  The coins are made with a reasonable standard of care for a 1-guy hobby project given the budget I put into it.  That said, if you've got one, I'll probably buy it from you.

Beyond that, I don't have the means or the practical ability to test the physical coins with every kind of ray or chemical or imaging technology out there, so if someone were to find an exploit that allowed the private key to be read on my coins without ruining the hologram, I would be more likely to make a posting or a statement that such had occurred, so everyone would know that they need to protect themselves from it, rather than buy back all the coins.  Of course, any announcement like that would be unfortunate - but given that the coins are collected far more than they are circulated, that would be only a letdown, rather than a major vector for transactional fraud.  I assume people would keep their coins like they probably already do, and would have nothing to worry about with respect to their own coins.

If I were to formally guarantee the physical coins, then at any point an exploit were found, that guarantee would amount to an invitation for people to exploit the BTC off and then redeem the guarantee sell them back to me, and that's inconsistent with my goals for the project.  I believe the coins are reasonably secure, but I expect that as Bitcoin becomes more prominent, that there will be advances in the security of physical bitcoins produced both by me and by others, as well as the attacks made against them, and the first iteration of the physical bitcoin definitely won't be the last.

If coin material (such as unused holograms or unfunded coins) were to be lost or stolen, I would probably make a judgment call.  For a small amount, I would probably offer to redeem them for face value.  For a large amount, I would probably announce that the material had been stolen, provide any information that identifies the stolen material, and then probably use a new design that is clearly distinguishable.  Keep in mind, the project is to promote Bitcoin, promote a proof of concept, and provide a neat-looking example of a good honest coin... but not to insure against things I couldn't possibly reasonably control.  Fortunately, to my knowledge, there have been no occurrences of this kind to report, and to the best of my knowledge, all coins in the wild are either legitimate and funded, or (at worst) are waiting to be funded when enough time has elapsed to ensure they've cleared customs of their buyer.

Mike, would you consider having a buy back guarantee for the face value of any casascius coin as long as the hologram is intact and genuine?

OK thanks casascius. If you're always going to be present then it's not too worrisome I'm aware that this would be the case anyway with a party of course, but I got the impression (from earlier posts) you were planning to move to a system of production where you'd be hiring people to put the coins together for you. I figured they'd be working in isolation rather than necessarily ensuring that you'll always be there, around the same table, doing it with them. I hope they sell very well!

Yep... it's to always be present and account for all the materials.  Nobody makes coins if I'm not there and helping.  And I only need help on the 1 BTC coin.  The 25 and the 100 BTC pieces get sold much less frequently and it is no big deal to just do these myself.

I am pretty certain none of the keys have been compromised, so the claims process idea is unnecessary.  If I thought I had a batch of coins that contained any compromised keys, I would probably just move the whole batch to the "bargain bin", rip them open, and sell them as "opened coin samples so you can see what's inside" (like I do on my website).  If you ever came across an intact Casascius coin that showed it was spent on Block Explorer, I would likely buy it off you at well above face value just to see what went wrong.

I pictured Mike and his friends all sitting around the dining room table putting stickers on bitcoins while they chat/watch football/whatever.  In a setting like that, it would be pretty obvious if someone was trying to take pics of the private keys with their phone or trying to copy them down.  Probably a good portion of the friends wouldn't even be personally interested in bitcoin.

The coins look great, but how can you be sure that your friends won't make copies of the private keys they're handling? I have some trust in you to do an honest job, but I don't necessarily trust your friends and especially some employees of yours not to make a few secret copies. Do you have some procedure to stop this?

Just thinking out loud, but if you really need help maybe the best thing to do would be to keep track of which keys you've assigned to which employees (and make it clear to them that they are responsible for the keys they handle). Since owners of the coins in the wild can always look at the block chain to verify the balance on the coin, they can always check if the digital bitcoins were ever moved. Then you could have a claims process on your website, whereby people can send back their unopened coin as proof that one of your employees must have kept a copy of the private key. Then you can use your records to track down which employee it must have been. It's a not perfect solution because they might be long gone by the time they cash out, but at least you'll know never to work with them again. And then you could refund the claimant with a new coin that you seal personally to ensure that it won't happen to them again.

And in practice, there's much fewer.

I am fairly certain there's fewer than 4000.  I will probably keep producing some originals for a while (especially to make use of the materials - they were costly), but that could change on a whim as new methods of production are developed.

I am still doing the originals at the same price.  I am sure I will eventually retire them, but I also intend to bring the series 2 in at a lower price once I have a nice big party where a bunch of friends come over and we put these coins together.

(That's the biggest difference - with that little window, I can be 100% certain the private key on the inside matches the address on the outside).


Same format, just length 30 instead of 22.  Same rules apply.  In one of my specs, I had drafted that lengths 22, 26, and 30 were valid lengths.

Incidentally, I gained access to a laser cutting machine, which allows me to precisely cut those little private key circles in an automated fashion (before I was using an oversize hole punch, each circle punched out by hand).  Because of the laser cutting, I can get the measurements more precise, and fit more characters on that little circle.  Thirty is better for security, especially on the off-chance that the window could allow some of the characters to somehow be seen from outside.

new private key format ?

According to the FAQ (https://www.casascius.com/faq.aspx), under 11k.

I like them... How many originals do you still have for sale?

I like these new coins a lot better!
Good job

i guess this means you will stop making the Original Series.

just how many of the Original Series were made?

What they look like:



When they'll be available: NOW AVAILABLE ON BOTH CASASCIUS.COM AND MEMORYDEALERS.COM

I have the materials in, now am working on the best way to produce them in quantity.

Note, the above image was produced with a scanner, so it sort of flattens out the holographic effect.  The hologram sparkles exactly the same way as the first series (see my avatar image).

Changes include:

• Denomination is shown on hologram
• Bitcoin address shown through a transparent window, rather than overprinted
• Internally, a 30-character sha256 private key code is used (instead of 22)
• Fixed a typo on the hologram