Wallet for off-grid transactions

[Toro2000]

Is this possible to implement with bitcoin?

Some ideas:

- bitcoin would be transfered off the grid using only smartphone and NFC
- trusted execution environment technology could be used

This would solve some issues if it is possible. Such as trading in no Internet environment, like is the case in half of the world.

What's your thought?

[Olaphash]

Bitcoin transaction need confirmation from miners and It would be totally impossible to send offline transactions or make offline trades.

[bitmover]

The problem of places with no internet connection is related to broadcasting the transaction to the nodes. After the broadcast, the transaction would be in the mempool and it would be a normal transaction

There are some ideas about broadcasting bitcoin transactions via radio

https://blockonomi.com/bitcoin-transactions-radio/

The concept of broadcasting Bitcoin transactions over radio transmissions has been around for several years. In 2017, the notion was expanded on in a proposal by crypto pioneer Nick Szabo and Elaine Ou detailing the benefits that radio transmissions using shortwave frequencies could have on Bitcoin’s network resilience.

Recently, TxTenna launched, enabling offline Bitcoin transactions through a collaboration of GoTenna — the radio mesh network communication company — and Samourai Wallet, the privacy and security-focused Bitcoin wallet.


Understanding How Weak-Signal Radio Communications for Bitcoin Work

Szabo and Ou’s proposal outlines weak-signal high-frequency radio waves as a mechanism to increase the multi-homing of the Bitcoin network. By increasing the diversity of node connections, the network can become much more resilient, which enables a more isotropic (i.e., trust-minimized) network.

[o_e_l_e_o]

Is this possible to implement with bitcoin?

The only way I am aware of to perform truly offline bitcoin trading is through the use of devices such as Opendime (https://opendime.com/), which is a tamper-proof USB wallet you can hand from person to person and needs to be destroyed to access the funds stored within.

To move bitcoin between wallets there must be a connection to the internet at some point. This could be via radio or mesh networks as bitmover has suggested, or also potentially via phone lines, SMS or by simply storing the transaction until internet access is established. The problem with all these methods is it introduces a new element of trust. Let's say we make a trade and I sign a transaction sending bitcoins from my wallet to yours, and give you a copy of the transaction. You now set about transmitting that transaction to the network via radio or some other non-instant method. In the meantime, unknown to you I have internet access on another device, and send all the coins to another address. The signed transaction you have in your possession is now useless, and I have stolen from you.

In your suggestion of smartphones and NFC, the process could easily by manipulated by a single person with internet access.

[hugeblack]

You can create that wallet and you can use Bitcoin but you need to connect to the internet to "sync."
I think the best solution is to have an independent platform based on BTC as a balance.

The best solution I can think of is to lock the transaction (off-chain payment smartphones and NFC) when using the network so that it can only be unlocked after the other device connects to the Internet.