Topic: Transfer bitcoins without internet (Read 1083 times)

 What is physical bitcoin? Is it like gold coins?

It seems that the idea of having offline transactions is disappearing slowly because most of the developers are not thinking about it or most of them making it least of their priorities. But someday we gonna need offline system. I even tried to discuss the SMS based system for sending and receiving bitcoins and system does look simple to implement if proper minds are put together. On giant scale we will only need to use existing infrastructure that everyone knows about it. The EDGE and 5G is the key for this.

Paper wallets are not the key for this. That’s most insecure one and it’s time consuming. You need loaded wallets for that which ain’t good idea in the long run. Just hoping for some of the developers liking this idea someday.

It has been discussed somewhere in the forum and a user recommended https://blockstream.com/satellite/ where you can configure any satellite antenna in your area to receive signals from the blockstream satellite network and transact bitcoin free of charge without any internet. You'll just have to set it up, position the antenna to face the sky, and read carefully their main page, the requirements and help. The blockchain technology keeps advancing, people shouldn't bother about some barriers, as most barriers are being worked on by developers and settled to avoid future dispute, which may erupt from the government.

To designed anything that will bring this possibility will definitely be a deviation from is core purpose of Decentralization and transaction confirmation mechanism. The only thing that can happen is to design a more sophisticated Technology that can provide Internet connection to the world.  I would suggest an internet Network that will be able to cover a continent or more through the use of satellites just like the ones used for transmission for television stations.


I think this system will the most risky, it will introduce more theft into the system. More fraudulent activities will take over the whole system

Let me ask you, what cold wallet did you teach your community that they should use? then why don't you try to put an internet or wifi connection there in your place or house, this is just my suggestion.

       So when someone pays you bitcoin using their cold wallet, you can connect them to your wifi spot so that you can do the transaction properly and not have problems like that.

It's great that you have implemented a BTC payment system, but offline transactions require some technical know-how. You can explore options such as using paper wallets or hardware wallets to facilitate offline transactions, but it's important to educate your community members about the risks involved in handling cryptocurrencies offline.

It would be a milestone achievement to have bitcoin transacted and signed offline without internet connection as such tech would be of greater advantage to those in the hinter areas that lacks internet access like yours do. But for now, there's no such means of bitcoin payment without the use of the internet. However, in the nearest future there should be a breakthrough, hopefully.
@OP,  I must say, I envy your zeal to bringing bitcoin to the doorstep of your community and the lack of access to internet shouldn't deter you.

Sure, you can sign your transaction offline and broadcast transaction online.
tool:
https://github.com/CryptoDappRun/Bitcoin-Signer-Wallet

Internet is definitely the most popular way Bitcoin transactions are broadcast across the blockchain network. Without it, thousands of computers around the world will not be able to validate the transaction to update the network. This will absolutly slow down the process of the transaction.
However, in case of total failure of internet, there are other alternatives to send bitcoin transactions. In fact in 2017, Blockstream, a company dedicated to improving Bitcoin functionality, has announced that they succeded to develop a method to send bitcoin via satellite without the need to have access to internet.
Since bitcoin transactions are completely  public, data can be sent and exchanged via other methods then the internet. However, due to it's efficiency, internet will remain the main way for bitcoin transactions.

You can print Paper wallets with small amounts of bitcoin on it and then have people exchanging Paper wallets, but then you have to obscure the Private key. Someone has to secure the private keys and then provide it to them, when the people want to extract their bitcoins to their own online wallets.

This is definitely not the ideal scenario to use Bitcoin, because it centralizes the control of the Private keys and there are no transactions being done on the Blockchain, but it is cheaper than doing it on the Blockchain. 

Basically write the private key on a piece of paper. Give it to the other fucker =D

Problem is, must forget about the private key, don't copy it !

One possibility comes to mind:

Some kind of service... that generates private keys in an encrypted form.

Give the password to the other fucker... give the private encrypted key to the other fucker.

Send money/bitcoins to this key.

So everybody remain blind, except the guy getting the private key...

He must then be able to decode it, have the password... Hmmmmm...

Homomorphic encryption might be a solution for this, or maybe not...

And otherwise seperate the encrypted private keys from password key into different channels, so that none of both... might help somewhat

Finally a technical solution:

The private key could stay encrypted. Using homopathetic encryption.

The password key could be given out... as well, possible also encrypted.

Both are then used to perform operations on the private key in a homopathetic encryption method.

Thus the only thing required is the possesion of both.

To prove to the system that both are in possession zero knowledge proof could be executed based on both possesions.

So that decryption of private key or password is never truely necessary.

Just ownership is enough...

However to be able to actually do anything with it, requires owner ship and plugging it into some system to ultimately use it with bitcoin system ofcourse...

However if such technology available, then both could be copied... but one must get access to both...

Little bit interesting.

No. You can not. You need the internet to verify the transactions of the blockchain. Let's assume I need to send bitcoins to MARS. If you can build a satellite network (Like bitcoin nodes), then you can send bitcoin to any planet.

While true, this does absolutely nothing to protect all the users who have already used that company or entity - it simply stops future users from falling victim to the same scan.

It is quite interesting that just a couple of weeks after I made that post, a highly trusted and respected user on this forum - yogg - did exactly what I said here and stole the coins from a whole bunch of collectibles he had made and secretly kept the private keys for.

It's not just an issue of seeing the current price, but then you need to make another bitcoin transaction. If there is internet, then we don't need to use physical bitcoin at all. If there isn't internet, then the merchant will need to have a physical bitcoin with the exact denomination already pre-loaded, and then the whole issue of trust comes back in to play yet again.

The power of evidence-based public trust rating by customers should not be underestimated. If a company does something untrustworthy, customer can just report it with proof, then other companies will want to do better to have better rating and outcompet the ones with bad rating who we expect should be punished if proven guilty. Customers also will avoid those with proven bad report/ratings.

In regards to what the poster you quoted said, I think we could just compensate the price change by giving changes to customers. If a customer comes to pay for a product that is worth $5 with $5 worth of physical satoshi, the seller can just give the customer $1 change if the satoshi becomes $6. Ofcourse you may still need the internet to observe the Bitcoin price change .. Alternatively the village could use fm, short or medium wave radio stations to monitor price change by dedicated price monitoring/broadcasting stations

     What kind of wallet do you suggest to your customers? So what country are you in now? Because here in my country we have local wallet apps that can be used with features that accept bitcoin and crypto other cryptocurrencies such as coins.h, Maya apps, and others.

I'll add that the 711 convenient outlets also become a way to get money into bitcoin going to coins, right?

Transaction malleability refers to the ability of a third party to change an already signed transaction. In this case you are referring to a service for broadcasting transactions, but this could also refer to any node which could change the transaction prior to relaying it to other nodes, or any miner which could change the transaction prior to including it in a block.

Transaction malleability does not allow the third party to change anything about the important parts of the transaction. They cannot change which coins are spent, which addresses these coins came from, which addresses they are going to, how much is going to each address, and how much is being spent as a fee. All of this information is covered by the transaction signature, and so if someone tries to change any of it, the signature would no longer be valid and the entire transaction would be rejected.

There are some parts of a transaction which are not covered by the signature, though, and so can be changed by a third party. While the core parts of the transaction stay the same as above, the outcome of any such change means the transaction has a different TXID. For most cases this is completely irrelevant. However, as we know, when you spend a bitcoin UTXO, the network identifies the UTXO you are spending based on the TXID of the transaction which created that UTXO. So if someone was to spend a UTXO from an unconfirmed transaction, and then that unconfirmed transaction was altered to have a different TXID before it was mined, the transaction spending those unconfirmed UTXOs would now be invalid, since it is referring to a TXID which no longer exists.

The whole point of segwit was to fix transaction malleability. The smaller transaction virtual size (which most people think was the real reason behind segwit) was a byproduct of fixing transaction malleability. While transaction malleability doesn't affect the vast majority of people, fixing it allows safely generating chains of unconfirmed transactions, which is core to how things like Lightning work.

So in summary the answer is no, a service for broadcasting transactions can't do any real harm to anyone who uses it (apart from invading their privacy, obviously). And if you want to avoid the possibility of transaction malleability altogether, just use segwit.

If there would be a service that receives transactions that are signed and ready to send. Would it be possible for the owner of this service to change something in the transaction to betray the sending person, or can a signed transaction not be changed/abused in any way?

I am not confusing airgapped wallets with broadcasting transactions as far as I know, you see the hr on the reply before I stated methods of sending transaction offline, there is no way I stated a broadcasting transaction on that part did I? I just summarized what had been discussed on the earlier replies.   Anyway, still thank you to the clarification.



Indeed since this idea and procedure had been brought up in the earlier replies I think there is no need for me to reiterate what you had been explained since it is very clear and easy to understand.

This looks like a really cool project. Have you used it, and does it work nicely? Can you use it to send Lightning payments to anyone, or only to other accounts within their system? The biggest obvious downside here is that it is entirely custodial. Would be great if you could instead run your own wallet on your phone, and instead simply send and receive transaction data and the like with their service via SMS.

You are confusing airgapped wallets with broadcasting transactions. It is of course entirely possible to run an airgapped wallet and transfer signed transactions to an online computer in order to be broadcast. What OP is asking is what to do if you do not have an online computer in order to broadcast your transaction. In this case you need to use something like radio (as I've discussed earlier in this thread) to send your transaction to someone who does have an internet connection and can broadcast your transaction for you.

There are methods stated on the earlier replies to send Bitcoin such as hardware wallet, QR code scanning etc.  But at the end of the day it needs to be broadcasted online for the blocks to confirm.  So there is no way to complete a transaction without using the internet.

It is worth noting that sending Bitcoin offline is way more complex than sending Bitcoin through internet.  Although these method increase the security I believe it has its own set of risks and limitation.

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Methods of sending Bitcoin offline as stated on earlier replies

• hardware wallet
• paper wallets
• QR code transaction
• Air gapped device
• infrared

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