BTC Offline Layer

[MX1971]

I’m working on a Bitcoin project designed for people in remote, hyperinflation-affected communities who lack access to banks, internet, or the knowledge to self-custody BTC. The solution is a tamper-evident, pre-funded paper certificate secured by a 2-of-2 multisig wallet. One private key is hidden inside the physical certificate; the second key is generated by a foundation or trusted entity and also securely embedded within the same certificate. A public Bitcoin address—derived from both keys—is printed on the outside, allowing anyone to verify its on-chain balance. BTC is sent to this address by either the certificate issuer or the foundation. This makes Bitcoin usable as an offline, cash-like medium of exchange while remaining secure and trust-minimized. I’m currently looking feedback.

[mcdouglasx]

I’m working on a Bitcoin project designed for people in remote, hyperinflation-affected communities who lack access to banks, internet, or the knowledge to self-custody BTC. The solution is a tamper-evident, pre-funded paper certificate secured by a 2-of-2 multisig wallet. One private key is hidden inside the physical certificate; the second key is generated by a foundation or trusted entity and also securely embedded within the same certificate. A public Bitcoin address—derived from both keys—is printed on the outside, allowing anyone to verify its on-chain balance. BTC is sent to this address by either the certificate issuer or the foundation. This makes Bitcoin usable as an offline, cash-like medium of exchange while remaining secure and trust-minimized. I’m currently looking feedback.

I wonder how you'll validate the funds in cases of document forgery if you don't have immediate, direct access to the blockchain.
Or what benefit would a rural area have from having Bitcoin if, due to their internet access issues, they couldn't use it in their daily lives?

I'd prefer to equip them with technologies like Starlink; it would be more productive and convenient for them, since this is practically centralizing access to Bitcoin for those users.

[dkbit98]

I’m currently looking feedback.

What feedback?  
You literally posted few vague sentences and concepts, that's nothing.
If you want people to understand your project than you need to add more details about it or post a link with more technical explanation and examples.

We already have different Bitcoin layers, and it's not the first time someone tried to create bitcoin paper notes for offline usage.

[Smartprofit]

As far as I understand, the paper certificate should function as a banknote or a bill? And it will be possible to pay by first checking the balance on the corresponding Bitcoin address using the public master key...

The idea itself seems interesting to me, but it has its own nuances. For example, I don’t quite understand how you can protect such a paper certificate from counterfeiting? How can you even look at such a paper certificate and understand whether it is genuine or counterfeit? I also don’t understand how you can hide two private keys inside the certificate? The question also arises, does the owner of the paper certificate have access to the private keys? If so, what prevents him from transferring all funds to another Bitcoin address after transferring the paper certificate to another person?

As far as I understand, the presence of a multi-signature prevents this? However, a multi-signature is also not a panacea, in fact, it introduces a new entity (a new legal entity) into the scheme.  What happens to these paper certificates if this new entity, this fund, goes bankrupt or its owner suddenly disappears?

And why is Bitcoin needed in this scheme at all? After all, the fund can simply issue a promissory note, and this promissory note can be used in further settlements. As far as I know, in many countries, legal entities can issue paper promissory notes.

[Amphenomenon]

I’m working on a Bitcoin project designed for people in remote, hyperinflation-affected communities who lack access to banks, internet, or the knowledge to self-custody BTC. The solution is a tamper-evident, pre-funded paper certificate secured by a 2-of-2 multisig wallet. One private key is hidden inside the physical certificate; the second key is generated by a foundation or trusted entity and also securely embedded within the same certificate. A public Bitcoin address—derived from both keys—is printed on the outside, allowing anyone to verify its on-chain balance. BTC is sent to this address by either the certificate issuer or the foundation. This makes Bitcoin usable as an offline, cash-like medium of exchange while remaining secure and trust-minimized. I’m currently looking feedback.

This is almost the same as not your key notes your coin because you are dependant on another party before you can eventually use your bitcoin.

Also I think it has other flaws for others to get owners funds especially if they lay their hands on the certificate.

[BitGoba]

I’m working on a Bitcoin project designed for people in remote, hyperinflation-affected communities who lack access to banks, internet, or the knowledge to self-custody BTC. The solution is a tamper-evident, pre-funded paper certificate secured by a 2-of-2 multisig wallet. One private key is hidden inside the physical certificate; the second key is generated by a foundation or trusted entity and also securely embedded within the same certificate. A public Bitcoin address—derived from both keys—is printed on the outside, allowing anyone to verify its on-chain balance. BTC is sent to this address by either the certificate issuer or the foundation. This makes Bitcoin usable as an offline, cash-like medium of exchange while remaining secure and trust-minimized. I’m currently looking feedback.

As I understand it, these would basically be like paper banknotes backed by Bitcoin. Honestly, it's not a bad idea  especially since everything is verifiable and it avoids the kind of abuse we saw with gold.

Most people don’t know that gold actually stopped being money a few hundred years ago. Back then, moneylenders and exchangers started offering gold storage services. People would deposit their gold and get paper certificates in return. Those paper certificates eventually started being used as a medium of exchange because no one wanted to go pick up the physical gold every time.

The problem started when moneylenders realized people rarely came to collect their gold. So they began printing more paper certificates than the gold they actually held  and lending those out. That’s basically how banks and the fiat debt-based money system were born.

[Bitcoin Smith]

Looks like you inspired the idea from Casascius coins

Which was created with the purpose of enabling f2f transactions with bitcoin but what you are suggesting is trusted third party is not something that will be encouraged in decentralization and how you are going to ensure that the keys are not tampered? It must be based on the trust all the time that doesn't make any better.

They better be enjoying their life without internet and doesn't need to trust one more entity for the money they use.

[aoluain]

Looks like you inspired the idea from Casascius coins

Which was created with the purpose of enabling f2f transactions with bitcoin but what you are suggesting is trusted third party is not something that will be encouraged in decentralization and how you are going to ensure that the keys are not tampered? It must be based on the trust all the time that doesn't make any better.

They better be enjoying their life without internet and doesn't need to trust one more entity for the money they use.

or to be more precise > https://www.polymerbit.com/

The idea already exists and has done for a number of years by others apart from
polymerbit. My first concern is not as others have posted about the security
but instead the durability of the note in general circulation where its possibly
folded and handled by many people.

If its an offline certificate and I am receiving it as payment I would like to verify
its loaded value by checking online so the offline feature doesnt matter to me.

I suspect that if those who dont have access to banking or the internet wont trust a
3rd party paper certificate without first a lesson and explanation about Bitcoin

[odolvlobo]

What you are describing is called a "physical bitcoin". The idea has been around since the beginning, but it never really gained acceptance. One of the reasons might be that the cost of manufacturing is high.

If you are using multi-sig to prevent either party from knowing the other key, then you need a process that prevents the manufacturer of the notes from knowing the keys.

[ABCbits]

Aside from what other member have said, your idea also pose some similarity with opendime from coinkite[1]. Although opendime is less suitable for daily usage, as it uses USB stick rather than paper.

[1] https://opendime.com/