Casascious coins had the private key etched in brass. These seem to be able to rotate keys. That way you can be sure the previous owner won't sweep. Similar to opendime in that you have to break it to claim.
iirc, aren't there laws prohibiting the production of something which looks like fiat, but which isnt? Liberty Dollars were shut down for this reason. I thought Casascious was ceased for the same reason. Casascious def wasn't ceased just because it had a static private key.
I'd recommend making these not have a resemblance to domestic or foreign fiat notes.
Close. The Casascius coins had a private key underneath a tamper-evident hologram sticker.
This seems more like the OpenDime. Where to redeem it you physically alter it (by cutting the "wire" (trace) so that it then changes state to reveal the private key.
offline cash is cool but I think the old tried and tested method is what's going to work but i understand that it is currently regulated out of existence.
Its where its a basic paper note, redeemable for gold bitcoin on demand. You are obviously trusting the issuer in this case but with this trust comes a reduction in cost but also an increase in durability among other things. Not sure NFC tags can last more than a 10 years- But who knows.
Physical notes for just holding doesn't really make sense, because there are better ways for cold storage. The main purpose of a physical note is to enable bitcoin to be used as a medium of exchange. It's easy to exchange with instant finality, it protects privacy, and it works in offline settings.
I skimmed through the patent, but I'm still confused how it works. It is a multi-sig wallet which can be re-keyd with just one key, but can't be spent without cutting it. How does it exactly work?
Its an interesting design. I'm skeptical of course, but still it might be useful for the "something you can hold in your hand" crowd. I might not want to put my main stack into it, but I'd try a spending amounts worth.
Wow, amazed we missed this. Thanks for posting @nullcount.
As a few folks notes, the intention here isn't storing your whole stack in these. They're meant to complement BTC in cold storage. Our primary intent is that they are tools for gifting an education. Onboard a family member quickly with a beautiful piece that they can share. Show one off to a nocoiner and help them understand that Bitcoin is money.
We do not load notes, you do. We store an encrypted private key on each note (we generate the key) and you add a user key in plaintext. From those two you send the funds to a multisig generated in our app. We release the decryption key when you cut the note (we can authenticate that via the app). If we die or censor, the multisig downgrades to just the user key after Jan 3 2029. You can re-key notes that were loaded by untrusted parties. If you load less than face value, note scans as invalid. If you load more than face value, the remainder is used for fees during load.
The notes contain currency-grade security features in the printing (not that these really matter, it's all about the keys on the NFC chip -- but they look cool) and use a resilient synthetic paper.
Happy to answer any other questions here, or at @offlinecashco.
goldbitcoin on demand. You are obviously trusting the issuer in this case but with this trust comes a reduction in cost but also an increase in durability among other things. Not sure NFC tags can last more than a 10 years- But who knows.